Gastric Carcinoids and Their Precursor Lesions A Histologic and lmrnunohistochernical Study of 23 Cases

Cesare Bordi, MD,"s+ Ji-Yao Yu, MD,*$ Maria Teresa Baggi, MD," Carla Davoli, MD," Francesco P. Pilato, MD," Giuseppe Baruzzi, MD,+$ Giorgio Gardini, MD,§ Giuseppe Zamboni, MD, 11 Giuseppe Franzin, MD,7 Mauro Papotti, MD,# and Gianni Bussolati, MD,+,#

A histologic and immunohistochemical study was carried out in 23 unselected nonantral gastric carcinoids and their precursor lesions classified according to Solcia et 01. None of the patients showed Zollinger-Ellison syndrome. Two variants of carcinoids showing distinctive pathologic and pathogenetic characteristics were identified on the basis of presence or absence of associated chronic atrophic gastritis type A (A-CAG). Chronic atrophic gastritis type A was found in 19 cases showing either single or multiple neoplasms, tumor extension limited to the mucosa or submucosa, consistent endocrine cell precursor changes in extratumoral mucosa, and consistent hypergastrinemia and/or G cell hyperplasia. Associated precursor lesions were only hyperplastic in all but two cases with single carcinoids whereas they were also dysplastic in all but one case with multiple carcinoids. The four tumors arising in nonatrophic mucosa were all single, more aggressive, and not associated with extratumoral endocrine cell proliferations or with signs of gastrin hypersecretion. Tumor cells were diffusely immunoreactive for chromogranin A and synaptophysin but usually negative for chromogranin B or HISL-19. Scattered serotonin cells were found in ten carcinoids. They were more frequent in infiltrating than in intramucosal tumors as were the less represented pancreatic polypeptide cells whereas the reverse was found for alpha-subunit-containing cells. These results are of relevance for tumor pathogenesis and may provide the rationale for a less aggressive therapeutic approach in the patients. Cancer 67:663-672,1991.

EFORE THE INTRODUCTION of routinely feasible en- B doscopic gastroscopy, gastric carcinoids were mostly

Presented in part at the Annual Meeting of the United States and Canadian Academy of Pathology, Boston, Massachusetts, March 4-9, 1990.

From the *Institute of Pathological Anatomy, University of Parma, Parma, Italy; the $Division of Pathological Anatomy, Arcispedale S. Maria Nuova, Reggio Emilia, Italy; the lllnstitute of Pathological Anatomy, University of Verona, Verona, Italy; the lIDivision of Gastroenterology, USL 25 of Veneto Region Hospitals, Verona, Italy; and the #Department of Biomedical Sciences and Human Oncology, Section of Pathological Anatomy, University of Turin, Italy.

4 Recipient of a fellowship of the "Direzione Generale per la Coop- erazione allo Sviluppo" of the Italian Ministry of Foreign Affairs.

Supported by grants from the ?Italian Association for Cancer Research and from the Italian Ministry of Public Education.

Address for reprints: Cesare Bordi, MD, Universiti di Parma, lstituto di Anatomia Patologka, 1-43 100 Parma, Italy.

Accepted for publication July 2, 1990.

regarded as a pathologic curiosity accounting for about 3% of all gastrointestinal carcinoids. ' Recent studies, however, have reported an incidence of gastric carcinoids as high as 31.2% of all gut carcinoids.2 Moreover, endo- scopic screening may disclose these tumors in up to 9% of patients with pernicious anemia (PA), a condition at risk for the development of such neoplasm^.^ Gastric car- cinoids may also arise during long-term treatment with powerful inhibitors of gastric acid secretion, a finding first observed in toxicologic experiments on rodent^^-^ and then substantiated in some cases of Zollinger-Ellison syn- drome (ZES) and multiple endocrine neoplasia type I (MEN-I).7,8 Convincing evidence has been provided that in these conditions, as well as in hypergastrinemic chronic atrophic gastritis (type A, A-CAG) with or without PA, the growth of gastric carcinoids is dependent on the

663

664 CANCER February I 199 1 Vol. 67

trophic effect of inappropriate sustained release of gas- trim9-13

On this basis it has been p r o p o ~ e d l ~ ~ ' ~ that instead of total or subtotal gastrectomy, the patients may be treated with the less mutilating antrectomy, which removes the bulk of gastrin-secreting cells and may induce regression of carcinoids and their precursor lesions.'6-18 In hyper- gastrinemic patients development of tumors occurs through a hyperplasia-dysplasia-neoplasia sequence in which specific histopathologic lesions, recently classified by a panel of experts" (Figs. 1 A- 1 F), may provide useful information on the extent of risk of tumor development. Moreover, the gastric endocrine cells undergoing hyper- plastic changes in hypergastrinemic conditions have also been found to express a novel peptide, the alpha-subunit of glycoprotein hormones (GPH-a), virtually absent in subjects with normal gastrin circulating levels.20-21

In view of the forgoing the practicing pathologist not only may have increasing occasions of encountering this type of tumor but also may be requested to evaluate whether the tumor may benefit of antrectomy or to in- dicate whether the patient is at risk of developing gastric carcinoids.

In this report we have performed a histologic and im- munohistochemical investigation on an unselected series of gastric carcinoids collected from different institutions. The study (1) differentiates specific types of gastric car- cinoids with likely different pathogenetic background and related implications on therapeutic treatment; ( 2 ) evalu- ates the characteristics and the frequency of precursor le- sions which may be found in routinely processed material from patients with gastric carcinoids; and (3) monitors the immunohistochemical expression of GPH-a or other neuroendocrine substances in different tumors and in the whole spectrum of changes forming the sequence from simple hyperplasia to frank neoplasia.

Material and Methods

The basis of the current study is formed by nine cases of gastric carcinoid tumors recovered from the surgical pathology files of the Arcispedale S. Maria Nuova (Reggio Emilia, Italy); six from those of the Institute of Patholog- ical Anatomy, University of Verona (Verona, Italy): five from those of the Section of Pathological Anatomy, De- partment of Biomedical Sciences and Human Oncology, University of Turin (Turin, Italy); and three received from other institutions. One case has already been published as single case report.22

Only classical carcinoids were included in the study whereas solid-type gastric carcinomas, some of which are of endocrine nature as shown by staining with neuroen- docrine markers,23 were not considered. Of 23 patients investigated, 1 1 were male patients and 12 were females

(Table 1). Their ages ranged from 15 to 75 years (mean, 54.9). None of these patients had symptoms suggesting carcinoid syndrome, peptic ulcer, or gastric acid hyperse- cretion. A follow-up was available for 18 patients (range, 0-4 years; mean, 1.9 years): all patients were alive and well, except two (Cases 10 and 14) who died because of independent concomitant cancer (of stomach and esoph- agus, respectively).

Formalin-fixed, paraffin-embedded tissues were avail- able for study in all cases and included either surgical specimens ( 14 cases) or multiple endoscopic biopsy spec- imens (nine cases). From each patient representative blocks of tumor(s) and extratumoral fundic mucosa were examined except one case in which only a specimen of tumor polypectomy including a small area of overlying mucosa was available. Blocks of antral mucosa were available in 14 cases. From each block serial 5-pm sections were cut and routine hematoxylin and eosin, Alcian blue- periodic acid-Schiff (AB-PAS), and Grimelius silver staining was carried out.

The immunohistochemical reactions were performed with overnight exposure at 4°C to the monoclonal anti- bodies or rabbit antisera listed in Table 2. The immu- nostaining was visualized with the avidin-biotin complex (ABC) procedure (Vectastain ABC Kit, Vector Labora- tories, Burlingame, CA) using diaminobenzidine tetra- hydrochloride as a peroxidase substrate. Control of the specificity of the immunoreactions was performed by in- cubating consecutive sections with nonimmune serum instead of the primary antiserum, or with the specific antiserum preabsorbed with an excess of the respective antigens.

Results

Tumor Pathologic Findings

Gastric carcinoids were single in 13 cases and multiple in ten. The tumors often showed polypoid configuration (Fig. 2) and were located in the corpus-fundus area in all cases except one (in which the transitional zone between corpus and antrum was involved). The histologic structure was typical24 in all cases showing either trabecular (Fig. 3 ) or solid (Fig. 4) arrangement. Oncocytoid changes of tumor cells, occasionally involving the whole neoplasms, were sometimes seen. As described in detail elsewhere2* in one case with multiple typical carcinoids the largest tumor was a composite neoplasm with atypical carcinoid and well-differentiated adenocarcinoma components.

The carcinoids were entirely intramucosal in four pa- tients, or infiltrated the muscularis mucosae (in five), the submucosa (nine), the muscularis propria (two), and the subserosa (three). In agreement with previous observa- t ion~?~**' submucosal invasion was commonly associated with pronounced desmoplastic reaction. Lymph node

No. 3 GASTRIC CARCINOID TUMORS - B o d et al. 665

FIGS. 1A-1F. Hyperplastic (A-B) and dysplastic (C-F) lesions of endocrine cells in the extratumoral mucosa of patients with gastric carcinoids classified according to Solcia et al. l 9 (A) Linear and micronodular hyperplasia. (B) Adenomatoid hyperplasia. (C) Enlarging micronodule (arrow) associated with adenomatoid hyperplasia. (D) Infiltrative lesion (arrow). (E) Fusing micronodules (arrowheads). (F) Nodule with newly formed stroma. (Immunostaining for chromogranin A: A, B, D, and E; and for synaptophysin: C and F.)

metastases of carcinoid tumor were documented in one case (Case 2 1). Two patients (Cases 10 and 18), one with single and one with multiple carcinoids, also presented a concomitant, independent gastric cancer (in both cases intestinal type, poorly differentiated adenocarcinoma). One patient with multiple gastric carcinoids (Case 14) was also affected by small cell carcinoma of the esophagus.

In 19 cases, ten with multiple and nine with single car- cinoids, the tumors were associated with chronic atrophic gastritis (CAG) in the extratumoral fundic mucosa with intestinal and pseudopyloric metaplasia. When available

for examination (n = 14), antral mucosa showed absence of atrophic lesions and hyperplasia of gastrin cells (see below), a finding consistent with the type A gastritis.28 In most patients carcinoids were confined to the mucosa or the submucosa, although in two cases tumor infiltration extended to the muscular wall and the subserosa, respec- tively.

In contrast, the extratumoral mucosa was either normal or with mild superficial inflammation in four patients. In all of these cases the tumor was single and diffusely infil- trating, with extension to the submucosa (in one case),

CANCER February I 199 1 Vol. 67

TABLE 1. Data on 23 Unselected Cases of Gastric Carcinoid Tumors

Tumor

D i a m e t e r Invasion Gastrin FOIIOW-UP Case Age/sex Location No. (cm) level cell status* (Yd

With A-CAG 1 2 3 4 5 6 7 8 9

10 I 1 12 13 14 15 16 17 18 19

20 21 22 23

Without A-CAG

15/M 37/M 88/F 72/F 53/F 66/F 5 l /F 54/F 56/M 62/F 75/F 39/M 53/F 56/M 55/M 49/M 63/M 75/F 36/M

55/M 42/M 27/M 75/M

C C C C C

CIA C C C C C C C C C C C C

I 2 2 1 7 3 6

> 10 1

>I0 I 1

>I0 > 10

1 I I 1

14

0.5 0.2-0.8 0.4-0.5

9 0.05-1.5 0.45-4 0.05-0.2 0.05-0.4

0.4 0.1-0.5

0.7 0.6

0.1-0.3 0.1-0.5

1 1.5 0. I 0.3

0.05-1.5

0.8 3.5 1.5 2

M MM MM SM SM M P SM SM M MM MM SM SM SM MM SM M M S

SM S, LN S M P

+++ (>1000) ++ (700)

NE +++ +++ NE

+++ +++ +++ ++ NE

+++ NE NE

+++ ++

+++ +++

+++ (2000)

(80) NE NE NE

Alive ( I ) Lost ( 3 ) Lost (2) Lost (6) Alive (2) Alive (3) Alive ( I ) Alive (4) Alive (2) Dead ( I ) ? Alive ( I ) Alive (2) Alive ( I ) Dead (0) f Alive (3) Alive (3) Alive (1) Alive (0) Lost (8)

Alive (2) Lost (8) Alive (4) Alive (3)

C: corpus; CIA: transitional zone between corpus and antrum: M: mucosa; MM: muscolaris mucosae; SM: submucosa; MP: muscolaris propria; S: serosa; LN: lymphnode metastascs; A-CAG: chronic atrophic gastritis type A; NE: not examined.

* +, ++, +++ denotes mild, intermediate, and severe gastrin cell hyperplasia, respcctively; nos. in parentheses indicate serum gastrin levels (pg/ml).

f Death due to coexistent independent cancer.

the muscularis propria (one) and the subserosa (two) (Fig. SA). One of the latter cases also showed lymph node me- tastases.

Extratumoral Endocrine Lesions considered.

with Grimelius silver method or chromogranin A (CgA) immunoperoxidase and classified according to Solcia et al. l 9 (Figs. 1 A- 1 F). Simple hyperplasia, which requires morphometric analysis for proper evaluation,'' was not

N o endocrine cell lesions were observed in the oxyntic mucosa of the four patients without CAG. In these cases rows of proliferating endocrine cells were found exclu-

Hyperplastic and dysplastic lesions of endocrine cells were evaluated in the extratumoral mucosa after staining

TABLE 2. List of Antibodies Used in the Present Inimunohistochemical Study of Gastric Carcinoids

Code Antigens Antibody type Working dilution Source

PHE5 Chromogranin A* M 1:400 Enzo, New York, NY Chromogranin B P 1 :2000 Dr. H. Winkler, Innsbruck, Austria Synaptophysin P 1 :400 Dr. F. Navone, Milan, Italy HlSL- 19 M 1:soo Dr. G. Eisenbarth, Boston, MA

PS- I0 Serotonin P 1:800 Sanbio, Uden, Netherlands A568 Gastrin P 1 :200 Dakopatts, Copenhagen, Denmark

Pancreatic polypeptide P 1:4000 Dr. R. E. Chance, Indianapolis, IN (bovine, BPP)

human chorionic Bethesda, MD gonadotropin

AFP-3 10784 Alpha-subunit of P 1:800 Natl. Pituitary Program, NIH,

A566 Somatostatin P 1:400 Dakopatts, Copenhagen, Denmark 0 5 Y Glucagon (N-terminal P 1:800 Dr. R. H. Unger, Dallas, TX

region)

M: monoclonal; P: polyclonal (rabbit); N I H National Institutes of * As identified on 2D-immunoblot (H. Winkler, unpublished data). t Cross-reacting with intestinal glicentin. Health.

No. 3 GASTRIC CARCINOID TUMORS - Bordi et a/. 667

FIG. 2. Equatorial section of an intramucosal polypoid carcinoid sur- rounded by a crown of elongated foveolae in a patient with gastric atrophy (chromogranin A immunostaining).

sively at the base of the glandular neck epithelium over- lying the tumor (Figs. 5B and 5C).

In contrast, the extratumoral mucosa of all cases with CAG showed various combinations of endocrine cell changes, the distribution of which is given in Table 3 . It may be noted that linear hyperplasia was present in all cases except two. It was most commonly found in areas of pseudopyloric metaplasia and was virtually absent in

FIG. 3. Chromogranin A immunoreactivity in a carcinoid with tra- becular structure.

FIG. 4. Diffuse synaptophysin immunostaining in a carcinoid with predominant solid arrangement.

foci of intestinal metaplasia. Also frequently seen was mi- cronodular hyperplasia which was usually located in the deep region of lamina propria or between the superficial bundles of the muscularis mucosae. Adenomatoid hy- perplasia or dysplastic lesions were either absent or infre- quent in cases with solitary carcinoids, their occurrence being usually associated with multiple tumors (Table 3).

Irnmunohislochernical Results

Table 4 summarizes our results dealing with two groups of antigens, general neuroendocrine molecules and specific hormones. Among the former CgA (Figs. 1 A-lD, 2, and 3 ) and, to a slightly lesser extent, synaptophysin (SP, Figs. 1C and IF and 4) were diffusely demonstrated in most cells of all types of lesions, either neoplastic or preneo- plastic. Expression of CgA was usually overlapping that of SP with the notable exception of the oncocytic-type areas which were reactive for CgA but not for SP. Chro- mogranin B (CgB) was not expressed by gastric carcinoids (except one case of multiple tumors) or by precursor le- sions. Immunoreactivity for CgB was found in some gas- trin cells and in occasional cells of metaplastic intestinal epithelium. Carcinoids expressing HISL- 19 were found in six cases, including two of four not associated with CAG whereas hyperplastic and dysplastic endocrine cells were positive only in patients with HISL-19 immuno- reactive tumors. Scattered cells heavily expressing HISL- 19 were found in the oxyntic glands, particularly in cases without mucosal atrophic changes.

When present, expression of the hormonal antigens in- vestigated was restricted to minor populations of scattered carcinoid cells (Figs. 6A-6C). Serotonin was the most fre-

668 CANCER February 1 199 1 Vol. 67

FIGS. 5A-5C. Gastric carcinoid not as- sociated with atrophic gastritis. (A) His- tologic survey showing widespread infil- tration of the entire gastric wall. (B) Pro- liferation of endocrine cells in the epithelium of glandular necks contiguous to tumor cell clusters. (C) Nonatrophic oxyntic mucosa with normally appearing scattered endocrine cells (arrows; Chrom- ogranin A immunostaining).

quent specific antigen detected in tumor cells (Fig. 6A), in particular in those of invasive carcinoids including three of four associated with nonatrophic mucosa. In contrast, it was rarely found in endocrine cell micronests (ECM) of micronodular hyperplasia even if associated with pos- itive tumors. Pancreatic polypeptide (PP) was detected in

tumor cells of four cases (Fig. 6B), all with invasive tumors and atrophic gastritis, whereas it was never shown in hy- perplastic or dysplastic lesions. Gastrin-containing cells were undoubtedly demonstrated in three cases. The most diffuse immunostaining was found in a case also pre- senting diffuse reaction of extratumoral hyperplastic and

No. 3 GASTRIC CARCINOID TUMORS - Bordi et al. 669

TABLE 3. Distribution of Hyperplastic and Dysplastic Lesions* of Extratumoral Fundic Endocrine Cells in 18 Casest of Gastric

Carcinoid Tumors and Chronic Atrophic Gastritis

Tumors

Single Multiple Total Lesions (n = 8*) (n = 10) (n = 18)

Hyperplastic lesions Simple hyperplasia Linear hyperplasia Micronodular hyperplasia Adenomatoid hyperplasia

Enlarging micronodules Fusing micronodules Microinvasive lesion Nodule with newly formed stroma

Dysplastic lesions

Absence of dvsdastic lesions

NE 7 4 1

2 0 2 1 6

NE 9 9 4

8 5 6 3 1

NE 16 13 5

10 5 8 4 7

NE: not examined. * Classified according to Solcia et t One case not included for insufficiency of mucosal tissue available

for examination.

dysplastic lesions. Another two cases showed weak im- munoreactivity of ECM but not of tumor cells.

Immunostaining for GPH-a appeared to be less fre- quent and intense in the current study based on formalin- fixed material than in a previous investigation employing Bouin-fixed tissues,20 a finding suggesting fixation influ- ences on antigen preservation. Cells containing GPH-a were found in tumors (mostly of noninvasive type) of four cases (Fig. 6C). They were also seen in all types of hyperplastic and dysplastic lesions showing the highest concentration in ECM (Fig. 6D). Scattered somatostatin tumor cells were found in one case with multiple carci- noids. No glicentin-containing cells were found in either preneoplastic or neoplastic endocrine cell lesions.

Gastrin Cell Status

Hyperplasia of gastrin cells, mostly of severe degree, was found in all 14 cases with A-CAG in which antral mucosa could be evaluated. Preoperative determination of fasting serum gastrin in three of these patients consis- tently showed abnormally elevated levels. Unfortunately, antral mucosa was not available for examination in the four cases without A-CAG. In one of these patients, serum gastrin was in the normal range.

Discussion

The current histologic and immunohistochemical study of 23 unselected cases of gastric carcinoids shows that tumor association with A-CAG, a criterion introduced by Solcia et af." in their classification of these neoplasms, is useful for distinguishing carcinoid variants with distinctive pathologic and, likely, pathogenetic characteristics.

Consistent features of the four cases not associated with A-CAG were as follows: (1 ) single tumor; ( 2 ) infiltration of the gastric wall (extending beyond the submucosa in three of four cases); and ( 3 ) lack of hyperplastic/dysplastic lesions of extratumoral endocrine cells. These results are in full agreement with those of six cases from two previous series.",26 Serum levels ofgastrin were in the normal range in the current case in which determination was done as they were in all four patients of Grigioni et ~ 1 . ~ ~ Moreover, no gastrin cell hyperplasia was found in the two cases reported by Muller et al.I7 Thus, these tumors appear to be independent from hypergastrinemia and should not benefit from antrectomy. Their aggressive behavior dic- tates their complete surgical ablation.

In our cases we have shown endocrine cell proliferation in the glandular neck epithelium contiguous with the tu-

TABLE 4. Immunohistochemical Results in 23 Cases of Gastric Carcinoids

Tumors

Not associated with CAG (n = 4) lnvasive (n = 17)t Total (n = 23) Intramucosal (n = 11)*

Antigens t * - ND t -t - ND + + - N D + + - N D

Chromogranin A 19 2 0 2 10 1 0 16 1 0 2 4 0 0 1 3 Chromogranin B 1 2 1 6 4 1 8 2 1 2 1 3 3

3 4 7 1 I 2 11 2 2 3 2 1 1 Synaptophysin 13 3 HISL-19 6 14 3 3 7 1 3 13 3 2 2 Serotonin 10 1 1 2 4 7 12 5 2 3 1 Gastrin 3 1 1 4 5 2 8 1 1 3 3 1 1 0 5 PP 4 17 2 1 10 4 13 2 0 4 GPH-CY 4 17 2 3 8 2 1 1 4 2 0 4 Somatostatin 1 20 2 1 10 1 16 2 0 4 Glucagon-N 0 21 2 0 1 1 0 17 2 0 4

CAG: chronic atrophic gastritis; P P pancreatic polypeptide; GPH-a: alpha subunit of glycoprotein hormones; Glucagon N: N-terminal region of the glucagon molecule common to intestinal glicentin; +: positive; -: negative: +: doubtful; N D study not done; HISL-19: unidentified

protein recognized by the monoclonal antibody coded HISL- 19.

vasive carcinoids. * Including intramucosal tumors of seven cases with concomitant in-

t Including all tumors infiltrating muscularis mucosae and beyond.

670 CANCER February 1 199 1 Vol. 61

FIGS. 6A-6D. Immunohistochemical expression of hormonal substances. (A) Uneven serotonin content in adjacent clusters of a carcinoid. (B) Scattered pancreatic polypeptide-containing cells located in tumor strands but not in the epithelium of intermingled glands. (C) Unusually high number of alpha-subunit immunoreactive cells in a carcinoid tumor. (D) Abundance of alpha-subunit in several hyperplastic endocrine micronodules (Avidin-biotin-immunoperoxidase; interference contrast optics).

No. 3 GASTRIC CARCINOID TUMORS - Bordz et nl. 67 1

mors. Such finding indicates that single gastric carcinoids not associated with A-CAG have a focal origin from the epithelial renewal zone. These tumors must be differen- tiated from those of patients with ZES and MEN-I which also arise in nonatrophic mucosa. The latter are usually multiple and are associated with diffuse mucosal prolif- eration of endocrine cells as usually observed in hyper- gastrinemic conditions. They are well represented in the series of Solcia ef a/.” but appear to be rare or absent in unselected collections of gastric carcinoids as ours.

In contrast, the relevant features of 19 cases with A- CAG were (1) a roughly equivalent proportion of single (n = 9) and multiple (n = 10) tumors, a result which is in agreement with some previous reports3,17*24.29 but con- trasts to the lack of solitary carcinoids in other s t~d ie s~~ ,~ ’ ; (2) absent or low invasiveness of the tumors which are confined to the mucosa or submucosa in all cases except two, a finding confirming the less-aggressive behavior of gastric carcinoids developed in A-CAG”; and (3) consis- tent association with hyperplastic or dysplastic lesions of extratumoral endocrine cells, which is in agreement with all previous observation^.^^"^'^^^^^^^

The hyperplastic/dysplastic lesions of extratumoral en- docrine cells are regarded as carcinoid precursor c h a n g e ~ ’ ~ ~ ~ ~ ~ ~ ~ . ~ ~ * ~ I and have been recently classified in a sequence with presumed increasing oncologic potential, useful for prognostic evaluation of patients at risk of car- cinoid development.” However, their incidence in pa- tients with established gastric carcinoids has not been as- sessed yet. Our study has shown that linear hyperplasia was universally present and that micronodular hyperplasia occurred in most cases irrespective on the number of coexistent carcinoids. In contrast, adenomatoid hyper- plasia and all types of dysplastic changes were mostly or exclusively restricted to patients with multiple tumors. These results may have pathogenetic implications sug- gesting a diffuse oncogenic potential in cases with multiple carcinoids and a local oncogenic stimulus acting on a background of endocrine hyperplasia in cases with solitary tumors.

Hyperplastic and neoplastic endocrine growths of the nonantral gastric mucosa in A-CAG patients are regarded to depend on the trophic effect of concomitant hypergas- trinemia.’-I3 In these patients, therefore, carcinoid tumors are candidate to be responsive to the gastrin withdrawal induced by a n t r e c t ~ m y . ’ ~ ” ~ ~ ~ ~ Indeed, postantrectomy regression of proliferating gastric endocrine cells was doc- umented in several cases.16-18 It has been proposed that single carcinoids can be adequately treated by tumor po- lypectomy, provided that the evolution of the endocrine hyperplasia in the remaining mucosa is monitored by en- doscopy and multiple biopsies on a regular f~llow-up.’~,~’ Our finding that single gastric carcinoids of A-CAG pa- tients usually are associated with hyperplastic but not with

dysplastic endocrine changes may provide the rationale for such therapeutic approach.

Two patients with gastric carcinoids and CAG also had gastric carcinoma, an association already r e p ~ r t e d * . ~ ~ , ~ ~ and likely depending on the influence of CAG common to both types of turn or^.^ An additional patient presented small cell carcinoma of the esophagus which apparently is a newly observed association.

Immunohistochemically no significant specific differ- ences were found between gastric carcinoids associated and those not associated with A-CAG. This observation is in accordance with the results of ultrastructural studies showing that in both groups the tumors are mostly com- posed of the same endocrine cell type, the enteroschro- maffin-like (ECL) cells. Thus, the distinctive features of the two tumor variants are related to differences in pathogenetic mechanisms rather than in cell composition.

General neuroendocrine markers such as CgA and SP were found to be almost universally expressed by endo- crine cells in both carcinoid tumors and precancerous le- sions. In contrast, HISL-19 and, in particular, CgB ap- peared of little or no interest as a marker for these changes.

im- munostaining for specific hormones usually revealed mi- nor populations of a scattered immunoreactive cells among which 5-hydroxytryptamine (5-HT) containing cells were more often represented. Interestingly, hormonal expressions were sometimes related to various stages of tumor induction and progression. In fact, 5-HT and PP were more frequently found in infiltrating than in intra- mucosal tumors. In contrast, GPH-a was expressed by three of 1 1 intramucosal and by two of 17 invasive tumors. This substance is virtually absent in oxyntic endocrine cells of normogastrinemic subjects and becomes manifest when the cells are exposed to hypergastrinemia.20 We have found that GPH-a has the maximal expression in a sup- posedly intermediate stage of the hyperplasia-dysplasia- neoplasia sequence, the hyperplastic micronodules, whereas it is less represented in frank neoplastic lesions. The expression of PP, which was found in carcinoids but not in normal cells or precursor lesions, is consistent with a condition of metaplastic differentiation within the tumor as described in nonendocrine gastric carcinoma^.^' Such a possibility must be taken into account when histogenesis of gastric carcinoids from metaplastic epithelium is ~ o n s i d e r e d ~ ~ , ~ ~ , ~ ~ Carcinoid tumors mostly composed of cells producing well defined hormones (such as gastri- nomas or somatostatinomas) were not found in our study. These tumors, however, are more common in the duo- denum whereas they are infrequent in the stomach, par- ticularly in the nonantral mucosa.’ 1~17,22

In conclusion, the histologic findings of gastric carci- noids and their associated precursor lesions are useful in identifying different tumor variants having discordant

In agreement with most previous

672 CANCER February 1 199 1 Vol. 67

pathogenetic implications and may provide the rationale for less aggressive therapeutic approach. Further investi- gation is warranted to elucidate the significance of rela- tions between tumor progression and immunohisto- chemical expression of hormonal substances.

REFERENCES

I . Sanders RJ. Carcinoids of the Gastrointestinal Tract. Springfield: CC Thomas, 1973.

2. Yoshino T, Ohtsuki Y, Shimada Y et al. Multiple carcinoid tumor combined with mucosal carcinoma in the stomach: A case report. Acta Pathol Jpn 1987; 37:1669-1678.

3. Borch K, Renvall H, Kullman E, Wilander E. Gastric carcinoid associated with the syndrome of hypergastrinemic atrophic gastritis: A prospective analysis of 11 cases. A m J Surg Pathol 1987; 11:435-444.

4. Ekman L, Hansson E, Havu N, Carlsson E, Lundberg C. Toxi- cological studies on omeprazole. Scand J Gusfroenterol 1985; 2O(suppl

5. Poynter D, Pick CR. Harcourt RA et al. Association of long lasting unsurmountable histamine H-2 blockade and gastric carcinoid tumors in the rat. Gut 1985; 26: 1284-1295.

6. Hirt RS, Evans LD, Buroker RA, Oleson FB. Gastric enterochro- maffin-like cell hyperplasia and neoplasia in the rat: An indirect effect of the histamine H2-receptor antagonist, BL-6341. Toxicol Pathol1988;

7. Mignon M, Lehy T, Bonnefond A, Ruszniewski P, Labeille D, Bonfils S. Development of gastric argyrophil carcinoid tumors in a case of Zollinger-Ellison syndrome with primary hyperparathyroidism during long-term antisecretory treatment. Cancer 1987; 59: 1959-1962.

8. Lehy T, Mignon M, Cadiot G et a/. Gastric endocrine cell behavior in Zollinger-Ellison patients upon long-term potent antisecretory treat- ment. Gastroenterology 1989; 96: 1029-1040.

9. Bordi C, Costa A, Missale G. ECL cell proliferation and gastrin levels. Gastroenterology 1975; 68:205-206.

10. Borch K, Renvall H, Liedberg G, Andersen BN. Relation between circulating gastrin and endocrine cell proliferation in the atrophic gastric fundic mucosa. Scand J Gustroenterol 1986; 2 1:357-363.

1 1. Solcia E, Capella C, Sessa F, Rindi G, Cornaggia M. Gastric car- cinoids and related endocrine growths. DigeWion 1986; 35(suppl l):3- 22.

12. Bordi C, DAdda T, Pilato FP, Ferrari C. Carcinoid (ECL cell) tumor of the oxyntic mucosa of the stomach: A hormone-dependent neoplasm? In: Fenoglio-Preiser C, Wolff M, Rilke F, eds. Progress in Surgical Pathology. Philadelphia: Field & Wood, 1988; 8:177-195.

13. Creutzfeldt W. The achlorhydria-carcinoid sequence: Role of gas- trin. Digestion 1988; 39:61-79.

14. Bordi C . Nonantral gastric carcinoids and hypergastrinemia. Arch Surg 1981; 116:1238.

15. Eckhauser FE, Lloyd RV, Thompson NW, Raper SE, Vinik AI. Antrectomy for multicentric, argyrophil gastric carcinoids: A preliminary report. Surgery 1988; 104:1046-1053.

16. Richards AT, Hinder RA, Hamson AC. Gastric carcinoid tumours associated with hypergastrinaemia and pernicious anaemia: Regression of tumours by antrectomy. S AJr Med J 1987; 725 1-53,

17. Muller J, Kirchner T, Muller-Hermelink HK. Gastric endocrine cell hyperplasia and carcinoid tumors in atrophic gastritis type A. A m J Surg Pathol 1987; 11:909-917.

18. Lundell L, Olbe L, Sundler F, Simonsson M, HQkanson R. Re-

108):53-69.

16973-287.

versibility of multiple ECL-cell gastric carcinoids by antrectomy in a pernicious anemia patient. Hepatogastroenterology 1989: 36:43-44.

19. Solcia E, Bordi C, Creutzfeldt W et a/. Histopathological classi- fication of nonantral gastric endocrine growths in man. Digeslion 1988; 41:185-200.

20. Bordi C, Pilato FP, Bertelk A, DAdda T, Missale G. Expression of glycoprotein hormone alpha-subunit by endocrine cells of the oxyntic mucosa is associated with hypergastrinemia. Hum Pathol 1988; 19580- 585.

21. Bordi C, DAdda T, Ceda GP et a/. Glycoprotein hormone alpha subunit in endocrine cells of human oxyntic mucosa: Studies on its re- lation with neuroendocrine tumours. Hepatogastroenterology 1990 37: 108-1 14.

22. Iwafuchi M, Watanabe H, Yanaihara N, Ito S. Immunohisto- chemical and ultrastructural characteristics of gastric carcinoids. Biomedical Research 1983; 4(suppl):307-3 14.

23. Murayama H, Imai T, Kikuchi M. Solid carcinomas of the stom- ach: a combined histochemical, light and electron microscopic study. Cancer 1983; 5 I : 1673-168 1.

24. Mendelsohn G, de la Monte S, Dunn JL, Yardley JH. Gastric carcinoid tumors, endocrine cell hyperplasia and associated intestinal metaplasia: Histologic, histochemical and immunohistochemical findings. Cancer 1987: 60:1022-1031.

25. Caruso ML, Pilato FP, DAdda T et al. Composite carcinoid- adenocarcinoma of the stomach associated with multiple gastric carci- noids and non-antral gastric atrophy. Cancer 1989: 64: 1534-1539.

26. Grigioni WF, Caletti GC, Gabrielli M, Marrano D, Villanacci V, Mancini A. Gastric carcinoids of ECL cells: Pathological and clinical analysis of 8 cases. Acta Pathol Jpn 1985: 35:361-375.

27. Ranaldi R, Lorenzini I, Montesi A, Bearzi I. Multiple gastric car- cinoids and pernicious anemia: Report of a case. Tumori 1986; 72:439- 445.

28. Strickland RG, Mackay 1R. A reappraisal of the nature and sig- nificance of chronic atrophic gastritis. A m J Dig Dis 1973; I8:426-440.

29. Itsuno M, Watanabe H, Iwafuchi M et al. Multiple carcinoids and endocrine cell micronests in type A gastritis: Their morphology, histogenesis, and natural history. Cancer 1989; 63:88 1-890.

30. Carney JA, Go VLW, Fairbanks VF, Moore SB, Alport EC, Nora FE. The syndrome of gastric argyrophil carcinoid tumors and non antral gastric atrophy. Ann Intern Med 1983: 99:761-766.

3 1. Borch K, Renvall H, Liedberg G. Gastric endocrine cell hyperplasia and carcinoid tumors in pernicious anemia. Gastroenterology 1985; 88:

32. Lattes R, Grossi C. Carcinoid tumors of the stomach. Cancer

33. Peison B, Benisch B. Simultaneous occurrence of malignant car- cinoid and adenocarcinoma of stomach. Arch Pathol Lab Med 1987; 107:99-100.

34. Capella C, Polak JM, Timson CM, Frigerio B, Solcia E. Gastric carcinoids of argyrophil ECL cells. Ultrastruct Pathol 1980 1:411-418.

35. Fiocca R, Villani L, Tenti P et al. Characterization of four main cell types in gastric cancer: Foveolar, mucopeptic, intestinal columnar and goblet cells. An histopathologic, histochemical and ultrastructural study of “early” and “advanced” tumours. Pathol Res Pract 1987; 182: 308-325.

36. Berendt RC, Jewel1 LD, Shnitka TK, Manickavel V, Danyluk J. Multicentric gastric carcinoids complicating pernicious anemia: Origin from the metaplastic endocrine cell population. Arch Pathol Lab Med

37. Quinonez G, Ragbeer MS, Simon GT. A carcinoid tumor of the stomach with features of a midgut tumor. Arch Pathol Lab Med 1988; I12:838-841.

638-648.

1956; 91698-71 1.

1989; 113:399-403.