Duodenal carcinoid tumor: report of a case diagnosed by endoscopic ultrasound-guided fine-needle aspiration biopsy with immunocytochemical correlation

Fine-needle aspiration biopsy is a reliable and accurate method for the endoscopic diagnosis of gastrointestinal malignancies and it is particularly well suited for evaluation of submucosal lesions. We report the cytopathologic findings of a case of malignant carcinoid tumor of a 44-year-old male who presented with melena and a nonhealing duodenal ulcer. Endoscopic ultrasound examination revealed a submucosal lesion in the pyloric region. Fine-needle aspiration revealed abundant cellularity with tumor cells arranged in sheets and loose groups and dispersed single cells in a clean background. Papillary fragments, capillaries cuffed by tumor cells, and rosette formation were also noted. The cells were moderate in size, round to oval, with a small subpopulation of spindle-shaped cells. The nuclei were uniform, round to oval, with smooth nuclear borders. The chromatin pattern was finely granular with a salt-and-pepper appearance. The cytoplasm of the cells was small to moderate in amount, pale, and showed fine granularity. The differential diagnosis included a neuroendocrine neoplasm vs. an epithelioid gastrointestinal stromal tumor. The tumor cells were focally positive for chromogranin and negative for CD34, supporting the diagnosis of a neuroendocrine neoplasm. The differential diagnosis of primary gastrointestinal carcinoid tumors from gastrointestinal stromal tumors can be very difficult in cytologic material. In cases when diagnostic material is scant, or only present on one smear, the use of smear division and cell transfer in order to perform immunocytochemical stains may be of considerable value to confirm the neuroendocrine nature of the neoplasms.

Foregut carcinoids: a clinical and biochemical analysis

BACKGROUND

Gastrointestinal foregut carcinoids make up a small percentage (3% to 6%) of all reported carcinoids. Because these tumors are so uncommon, comparisons between the subtypes have been difficult. The goal of this study was to compare the hormonal and clinical characteristics of gastric, duodenal, and pancreatic carcinoids.

METHODS

A prospective database of approximately 750 carcinoid patients seen by one author over 25 years was reviewed, and the 104 patients with gastric (33), duodenal (17), or pancreatic (54) carcinoids were selected as the subgroup for analysis. These patients were compared with regard to hormone levels, clinical course, treatment, and survival.

RESULTS

Duodenal carcinoids exhibited significantly lower serotoninergic hormone levels than did the gastric and pancreatic carcinoids (urine 5-hydroxyindoleacetic acid [mg/24 h], 5 +/- 1 vs 16 +/- 5 and 47 +/- 12, respectively, P = .03). Pancreatic carcinoids presented with more advanced stage (distant metastases 87% vs 42% and 20% for gastric and duodenal, respectively) and had worse outcomes than patients with gastric and duodenal tumors with 10-year survivals of 10%, 59%, and 58%, respectively (P = .003).

CONCLUSIONS

Pancreatic carcinoids produce higher levels of serotoninergic hormones and have a significantly higher stage and worse outcome than other foregut carcinoids. This study demonstrates that the organ of origin is an important determinant of hormonal activity and clinical course for patients with foregut carcinoids.

Primary anaplastic large cell lymphoma of the small intestine

We describe the clinicopathologic, immunophenotypic, and molecular findings in 4 cases of anaplastic large cell lymphoma (ALCL) arising in the small intestine. All patients were men with acute symptoms of gastrointestinal tract obstruction. The clinical preoperative diagnosis was gastrointestinal carcinoma in 3 cases, and pancreatic carcinoma in 1 case. Histologic examination revealed cohesive aggregates of neoplastic cells, with multiple vesicular nuclei, prominent nucleoli, and abundant amphophilic cytoplasm. There was no clinical or histopathologic evidence of enteropathy. All cases were CD30+, and all showed evidence of T-cell lineage with cytotoxic potential by expression of CD3, CD43, or CD45RO; T-cell intracellular antigen-1; or perforin. One tumor showed p80 and anaplastic lymphoma kinase (ALK) overexpression corroborated by the presence of the t(2:5). One tumor expressed Epstein-Barr virus latent membrane protein. In all cases, the tumor cells were negative for CD20, CD15, CD56, and cytokeratin. Polymerase chain reaction revealed clonal rearrangements of the T-cell receptor gamma-chain gene, without evidence of immunoglobulin heavy-chain gene rearrangement. The diagnosis of primary bowel ALCL is facilitated by immunophenotypic and molecular studies. With 24 months of clinical follow-up, only the patient with the t(2:5)-positive tumor is alive and free of disease, suggesting that p80/ALK overexpression may be a good prognostic indicator.

'Pyloric gland-type adenoma' arising in heterotopic gastric mucosa of the duodenum, with dysplastic progression of the gastric type

'Pyloric gland-type adenoma' is a recently described and very rare entity. We report a case of a pedunculated polyp of the duodenal bulb showing the features of pyloric gland-type adenoma. Heterotopic gastric mucosa was found adjacent to the tumour. Immunohistochemically, the tumour cells at the surface of the polyp showed foveolar-type mucin (M1) while most other tumour cells showed deep gastric mucin (M2), displaying a pattern of differentiation similar to the normal gastric mucosa. The polyp also showed villous or papillary structures with disorganization of gastric differentiation and marked increase of proliferating in foci cells. This is the first case of pyloric gland-type adenoma found to arise in heterotopic gastric mucosa of the duodenum, showing dysplastic progression of the gastric type.

Type VI collagen immunoreactivity in skeinoid fibers in small intestinal stromal tumors

By immunoperoxidase analysis for types I to VI collagen, elastin, cytoskeletal components and some glycoproteins, we found type VI collagen immunoreactivity in amorphous eosinophilic deposits (skeinoid fibers) in three small intestinal stromal tumors. Negative results were obtained for types I, II, III, IV and V collagen, elastin, laminin, ubiquitin, intracellular filaments such as actin, desmin, vimentin, calponin and caldesmon, and glycoprotein such as lysozyme, factor XIIIa, beta2-microglobulin, alpha1-antitrypsin and alpha1-antichymotrypsin. In two lesions, the periodic acid-Schiff-positive skeinoid fibers were also focally labeled for amyloid P component.

Carcinoid tumors of the ampulla of Vater: a comparison with duodenal carcinoid tumors

BACKGROUND

Although ampullary carcinoid tumors (ACs) are often categorized clinically as duodenal carcinoid tumors (DCs), there are distinct clinical and pathologic differences.

METHODS

Clinical, histopathologic, and immunohistochemical features of 12 ACs were compared with those of 53 DCs that did not involve the ampulla.

RESULTS

Patients with AC were ages 28-74 years (mean, 54.9 years); 8 were males and 4 were females. Five were white and three were black; the race of four patients was not known. The size of ACs ranged from 0.2 to 5.0 cm in greatest dimension. There were no significant differences between AC patients and DC patients with respect to male predominance, race, tumor size, and mitotic rate. The insular growth pattern was more common in AC; the cribriform type was more common in DC. Four of 12 ACs contained psammoma bodies, versus none of 53 DCs (P = 0.001). The rate of metastasis was similar in patients with AC (4 of 12, 33%) compared with DC patients (14 of 53, 26%). In DC patients, involvement of the muscularis propria, a size greater than 2 cm, and mitotic activity were significantly correlated with metastatic risk. In AC patients, tumor size and mitotic activity had no correlation with metastatic potential. One AC had features of an atypical carcinoid tumor; there were none in the duodenal group. One-half of patients with AC presented with jaundice versus 7% of patients with DC (P = 0.005). Three patients (25%) with AC had von Recklinghausen disease versus 0 of 53 patients with DC (P = 0.003). Immunohistochemically, tumor cells expressed somatostatin in 67%, serotonin and cholecystokinin in 17%, insulin in 25%, and glucagon and gastrin in 0% of ACs. In contrast, 56% of DCs expressed gastrin (P < 0.001).

CONCLUSIONS

Carcinoid tumors of the ampulla differ clinically, histologically, and immunohistochemically from carcinoid tumors elsewhere in the duodenum.

Antitumor effect of a neutralizing antibody to vascular endothelial growth factor on liver metastasis of endocrine neoplasm

Distant metastasis of gastrointestinal endocrine neoplasm is resistant to currently available treatments. Because hematogenic metastasis is dominant, anti-angiogenic drugs are expected to be a novel therapy for this neoplasm. In the present study, the therapeutic effect of vascular endothelial growth factor neutralizing antibody (VEGFAb) on liver metastasis of an endocrine neoplasm was investigated experimentally. Cecal transplantation into nude mice of small pieces of EN-1, a xenotransplanted human intestinal endocrine neoplasm, resulted in liver metastasis. A treated group (n = 19) received 100 micrograms/mouse of VEGFAb intraperitoneally on alternate days from day 10 after tumor transplantation, and the control group (n = 19) received saline. Five of the 19 control mice died of tumor progression, of which 2 could not be evaluated. The cecal tumor weighed 6316 +/- 2333 mg (n = 17) in the control group and 1209 +/- 837 mg (n = 19) in the treated group (P < 0.01) 6 weeks after transplantation. Liver metastasis developed in 16 of 17 control mice and in 2 of 19 treated mice (P < 0.01). The VEGF level of the whole cecal tumor in the control group was significantly higher than that in the treated group (305.1 +/- 174.1 vs. 54.7 +/- 41.2 mg; P < 0.001). VEGFAb did not cause any body weight loss (28.52 +/- 1.63 in the control vs. 28.44 +/- 1.71 g in the treated group). These results indicate that VEGFAb may be a novel therapeutic agent for endocrine neoplasm with distant metastasis.

Intestinal tumorigenesis in compound mutant mice of both Dpc4 (Smad4) and Apc genes

The DPC4 (SMAD4) gene plays a key role in the TGFbeta signaling pathway. We inactivated its mouse homolog Dpc4 (Smad4). The homozygous mutants were embryonic lethal, whereas the heterozygotes showed no abnormality. We then introduced the Dpc4 mutation into the Apc(delta716) knockout mice, a model for human familial adenomatous polyposis. Because both Apc and Dpc4 are located on chromosome 18, we constructed compound heterozygotes carrying both mutations on the same chromosome by meiotic recombination. In such mice, intestinal polyps developed into more malignant tumors than those in the simple Apc(delta716) heterozygotes, showing an extensive stromal cell proliferation, submucosal invasion, cell type heterogeneity, and in vivo transplantability. These results indicate that mutations in DPC4 (SMAD4) play a significant role in the malignant progression of colorectal tumors.

Small intestinal stromal tumors: a clinicopathologic study of 20 cases with immunohistochemical assessment of cell differentiation and the prognostic role of proliferation antigens

Small intestinal stromal tumors (SISTs), similar to their gastric counterpart, are complex because of their divergent cellular differentiation and because of the difficulty in accurately predicting their clinical outcome. We studied a series of 22 SISTs from 20 patients to characterize lineage and investigate prognostic morphologic parameters and possible histologic and immunohistochemical differences from gastric stromal tumors (GSTs) and to determine the potential prognostic value of proliferation markers. Cases were categorized into the three following groups based on mitotic count (MC) per 50 high-power fields and tumor size: (1) benign, n = 6 (< 5 MC, < 5 cm); (2) borderline, n = 6 (< 5 MC, > or = 5 cm); and (3) malignant, n = 10 (> or = 5 MC, any size). For the formalin-fixed, paraffin-embedded tissue sections, an immunohistochemical panel was used to characterize differentiation toward myogenic cells (pan-muscle specific actin [HHF-35], alpha-smooth muscle actin, and desmin), Schwann cells (S-100 protein), enteric glial (glial fibrillary acidic protein), and nerve cells (neurofilament). Cellular proliferative activity was assessed immunohistochemically using monoclonal antibodies to proliferating cell nuclear antigen (PCNA) and Ki-67 antigen (MIB-1) and a tumor proliferation index (TPI) was obtained as the percentage of positive-staining tumor nuclei. Clinical follow-up revealed that none of the benign tumors progressed (mean follow-up, 96 months). Half of the patients with borderline tumors were dead of disease (mean, 50.7 months), while 8 of 9 patients with a malignant tumor died of disease (mean, 24.6 months). By Cox Proportional Hazard Regression analysis, mitotic count, tumor size, and cellularity significantly predicted survival. PCNA, MIB-1, tumor necrosis, and atypia were not significant predictors of survival. All tumors stained with vimentin; 17 (77%) and 13 (59%) of the tumors showed immunoreactivity with muscle-specific actin markers (HHF-35) and alpha-smooth muscle actin, respectively. Only 1 tumor stained with desmin, and none stained with S-100 protein, neurofilament, or glial fibrillary acidic protein. Immunophenotypic characteristics did not differ among the 3 groups. The TPI for PCNA and MIB-1 significantly differed between benign and malignant tumors and between borderline and malignant tumors, but it failed to separate the benign and borderline groups. Compared with 52 cases of GST previously reported by us using the same criteria and antibody panel, these tumors were histologically and immunohistochemically indistinguishable. However, none of the 18 borderline GSTs progressed, while 3 of 6 patients with a borderline SIST died of the disease. Based on this series of 22 SISTs, we conclude the following: (1) MC, size, and cellularity are the best predictors of clinical outcome in SIST. (2) The majority of SISTs show smooth muscle differentiation based on their immunoreactivity with HHF-35 and alpha-smooth muscle actin). (3) The TPI for PCNA and MIB-1 correlated with MC but failed to predict survival for individual cases. (4) SISTs and GSTs are morphologically and immunohistochemically similar; however, SISTs seem to have greater malignant potential than GSTs of similar size.

Numerous eosinophilic globules (skeinoid fibers) in a duodenal stromal tumor: an exceptional case showing smooth muscle differentiation

A unique case of duodenal stromal tumor in a 51-year-old man is reported. The tumor histologically showed spindle cell proliferation and numerous eosinophilic globules. Most globules were composed of tangled 45 nm thick fibrils, which were ultrastructurally identical to 'skeinoid fibers'. The presence of glycogen granules in the tumor cells and the immunoreactivity for alpha-smooth muscle actin suggested smooth muscle differentiation. Focal ultrastructural findings also supported the smooth muscle nature of this tumor. There were no immunohistochemical and ultrastructural features indicating neural differentiation. In previous studies, the presence of such 'skeinoid fibers' was suggested to be a histological marker for neural differentiation in gastrointestinal stromal tumor. However, the findings in the present case suggest that numerous 'skeinoid fibers' can be identified in duodenal stromal tumor with smooth muscle differentiation, although this condition may be rare.

Gangliocytic paraganglioma of the duodenum: report of a case with immunocytochemical and ultrastructural investigation

A case of gangliocytic paraganglioma is reported in a 70-year-old female presenting as a polypoid tumor of the second portion of the duodenum. Immunohistochemical and ultrastructural features of the tumor indicate that gangliocytic paraganglioma of the duodenum (GPD) represents an unique tumor originating from the neuroectodermal derivative exhibiting dual phenotypic expression toward paraganglionic and epithelial (neuroendocrine) cells. These findings correlate well with the literature and it is further suggested that GPD belongs to the histopathologic spectrum of tumors derived from the neural crest. The findings offer a plausible explanation for histogenetic possibilities of the occurrence of pure epithelial tumors (i.e., carcinoid-like tumors) in the paraganglionic systems. The patient remains with no evidence of disease 4 years following a simple polypectomy.

Proliferative characteristics of differentiated cells in familial adenomatous polyposis-associated duodenal adenomas

The authors have previously shown that duodenal adenomas in familial adenomatous polyposis (FAP) patients typically reveal abundant cells with endocrine differentiation (ED), Paneth differentiation (PD), and goblet cell differentiation (GD). However, the biological significance and proliferative potential of these cells is unknown. To study the proliferative properties of cells with ED, PD, or GD in FAP-associated duodenal adenomas, the authors used a double-labeling immunohistochemical technique to detect simultaneously the presence of proliferating cell nuclear antigen (PCNA), and either chromogranin or lysozyme in individual neoplastic cells. Adenomatous cells with GD were identified morphologically and also evaluated for the degree of PCNA expression by immunohistochemistry. Duodenal adenomas and the adjacent nonadenomatous epithelium from 10 FAP patients were studied. Cells with ED, PD, and GD were present in all adenomas, and constituted 14.1%, 11.6%, and 17.7% of adenomatous cells, respectively. The overall proliferative index of nondifferentiated adenomatous cells was 33.3%, which was similar to the proliferative index obtained for adenomatous cells with GD (31.2%) and nonadenomatous crypt goblet cells (34.9%). In contrast, adenomatous cells with ED and PD showed a significant decrease in their proliferative potential (P < .001). Only 6.0% and 7.3% of cells with ED and PD, respectively, were proliferative. Nonadenomatous crypt endocrine and Paneth cells showed no proliferative potential (proliferative index 0%). These results suggest that, in the process of proliferation and differentiation, specific subpopulations of adenomatous cells attempt to recapitulate the biological characteristics of their normal counterparts in the small intestinal crypts. Adenomatous cells with ED and PD are hypoproliferative, a finding that is consistent with their differentiated phenotype and suggests that these cells may not participate as actively in the growth of these lesions.

Two cases of duodenal gangliocytic paraganglioma: immunocytochemical characteristics

Two cases of duodenal gangliocytic paraganglioma were studied by means of immunocytochemical methods using 41 kinds of antibodies. The tumors consisted of three histological types; carcinoid, ganglioneuroma and paraganglioma. Tumors of both cases exhibited immunoreactivity to at least one or as many as three of the following: calcitonin, calcitonin-gene related peptide, endocrine granule constituent, Leu7, neuropeptide Y and basic fibroblast growth factor. In addition, these tumors were also immunopositive for neuron specific enolase, S-100 protein, neurofilament protein, pancreatic polypeptide, chromogranin A, somatostatin, leuenkephalin, substance P and vasoactive intestinal peptide, as has been described in previous reports. In one case, tumor cells were immunopositive for adrenocorticotropin, bombesin, gastrin releasing peptide, myelin basic protein, neuroendocrine marker and tyrosine hydroxylase. Moreover, paraganglioma cells of tumors showed both argyrophilia and argentaffinity. These results suggest that duodenal gangliocytic paraganglioma may originate from embryonic neuroinsular complex.

Aberrant insulinoma of the duodenal bulb

A rare insulin-immunoreactive neuroendocrine tumor of the duodenum in a 54 year old male is reported. The incidentally identified tumor was located on the anterior free wall of the duodenal bulb and measured approximately 6 mm in diameter. Uncomplicated endoscopic resection of the tumor was carried out. The lesion exhibited classic histologic features of insulinoma of the beta-islet cell type with stromal amyloid deposition. In addition to positive reactivities of chromogranin A, neuron-specific enolase, synaptophysin, Leu 7 (CD57), cystatin C, CA15-3 and cytokeratin, the non-argyrophilic tumor cells were strongly immunoreactive for insulin and C-peptide. The stromal amyloid was clearly labeled for amylin. A few cells were stained for somatostatin, whereas other hormones were negative. Interestingly, a few isolated insulin-positive cells were identified in the non-neoplastic duodenal mucosa in the proximity of the tumor. Immunoelectron microscopy using paraffin sections disclosed insulin-immunoreactive secretory granules in the cytoplasm. The patient exhibited no signs or symptoms of hypoglycemia. Serum insulin levels were not measured prior to resection. No tumors were demonstrated in the pancreas. Magnetic resonance imaging revealed a 1 cm asymptomatic pituitary mass, in association with moderately elevated serum prolactin levels. The patient is currently being followed up in the outpatient clinic.

Use of an isotopic somatostatin receptor probe to image gut endocrine tumors

OBJECTIVES

To evaluate the effectiveness of indium In 111 pentetate (diethylenetriaminepentaacetic acid [DTPA]-D-Phe-labeled octreotide scintigraphy in the localization of gastroenteropancreatic neuroendocrine lesions, and to identify covert lesions, determine multicentricity, define the distribution of metastases, confirm complete removal of tumor postoperatively, and evaluate the efficacy of therapeutic embolization.

DESIGN

Unmasked comparison.

SETTING

Tertiary care referral center.

PATIENTS

We studied 28 patients over a 12-month period. Biochemical evidence of a gastroenteropancreatic tumor was present in 13 patients. Octreoscan 111 was employed in four patients with an ambiguous biochemical diagnosis of gastroenteropancreatic tumor. Postoperative examination to document complete tumor removal was undertaken in seven patients. In one patient, Octreoscan 111 was used to evaluate the efficacy of therapeutic embolization.

INTERVENTION

[111In]DTPA-D-Phe-octreotide scintigraphy.

MAIN OUTCOME MEASURE

Identification of somatostatin receptor-bearing neuroendocrine tumors.

RESULTS

Intravenous administration of [111In]DTPA-D-Phe-octreotide followed by whole-body gamma camera scintigraphy resulted in the localization of gastroenteropancreatic neuroendocrine tumors with 75% sensitivity, 100% specificity, 100% positive predictive value, 63% negative predictive value, and 82% overall accuracy.

CONCLUSIONS

While Octreoscan 111 has been shown to localize the majority of amine precursor uptake and decarboxylation system (APUD) cell tumors as well as various other somatostatin-positive tumors, this technique may also be useful in a number of other circumstances. These include prediction of tumors that will respond to octreotide therapy, identification of covert metastases, intraoperative identification of tumors, and postoperative surveillance. Use of an alternative isotope may provide a vehicle for the administration of local therapeutic radiation to tumor cells. The precise efficacy of Octreoscan 111 in the identification of lesions smaller than 3 cm with low-density somatostatin-2 receptor expression remains to be determined.

Epithelioid angiosarcoma of the intestinal tract with endothelin-1-like immunoreactivity

Two rare cases of intestinal epithelioid angiosarcoma arising in the sigmoid colon and small intestine are reported. The small intestinal tumours were located in the duodenum and upper jejunum. All tumours showed reddish-black protuberant masses with comparatively clear margins. Histology reveals solid and epithelioid growth of large polygonal cells, mimicking undifferentiated carcinoma. Vascular differentiation such as lamina containing red cells and intracytoplasmic vacuolization is noticed. Intense immunoreactivity to Ulex europaeus agglutinin I and JC70 (CD31), and sporadic positive reaction to factor VIII related antigen were detected in one case but not in the other. However, both tumours have cells which show intense endothelin-1 immunoreactivity. Positive immunostaining occurred with low molecular weight keratins suggesting epithelial differentiation and suggested epithelioid angiosarcoma as a diagnosis, a specific entity within angiosarcoma. Because of their histological features, epithelioid angiosarcomas may be confused with undifferentiated carcinomas. Endothelin-1-like immunoreactivity seems to be a good marker for this type of angiosarcoma, even when the tumour cells lack usual marker substances for endothelial cells.

Clear cell sarcoma of tendons and aponeuroses (malignant melanoma of soft parts) in the duodenum: the first visceral case

An ulcerated tumour was removed by a Whipple's operation from the descending part of the duodenum of a 38-year-old male. The tumour cells were mainly spindle-shaped, arranged in nests and had very prominent nucleoli. A few cells contained melanin and melanosomes. Immunoreactivity for S-100 protein and focally for HMB-45 was observed. These features are diagnostic for clear cell sarcoma of tendons and aponeuroses. Because no other primary tumour could be found and the search for similar cases from the literature was unsuccessful, we believe that this tumour is the first reported clear cell sarcoma in a visceral location.

Establishment of a CD4-positive plasmacytoma cell line (AMO1)

A human plasmacytoma cell line (AMO1) was established. The AMO1 cells had the light and electron microscopic characteristics typical of plasmacytoma cells and did not harbor Epstein-Barr virus. These cells expressed cytoplasmic immunoglobulin A kappa and the immunoglobulin heavy-chain gene (JH) and kappa light-chain gene (C kappa) were rearranged. Coexpression of a CD4 antigen and plasma cell antigens (CD38 and PCA-1) was an unusual and sustained feature. Neither the T-cell receptor beta nor the gamma chain gene displayed the rearranged form. Other lineage-specific surface antigens, namely T, B, monocytoid, and myeloid antigens, were all negative in AMO1. In accordance with the surface CD4 expression, polymerase chain reaction analysis indicated constitutive expression of CD4 mRNA, and the cytogenetic findings revealed that AMO1 cells had a derivative chromosome 12, which had a structural abnormality of the short arm carrying the CD4 gene locus. These findings provide strong evidence for the presence of CD4-positive malignant plasma cells and raise the possibility that the CD4 expression in the AMO1 cell line is closely associated with the derivative chromosome.

Argyrophil-negative G-cell duodenal carcinoid

A case of mono-hormonal-producing and functionally active G-cell carcinoid tumor of the duodenum is described. The tumor, found to be argyrophil negative, was investigated immunohistochemically and ultrastructurally. We report our results, then discuss the possible histochemical causes that can lead to the failure of argyrophilia, and direct attention to the possible misdiagnosis that can result from that failure.

Small Intestinal Stromal Tumors With Skeinoid Fibers

Microscopic appearances of spindle cell tumors of the gastrointestinal tract are suggestive of smooth muscle origin; however, they usually lack specific muscle cell features by electron microscopy and immunohistochemistry, thus justifying their designation as stromal tumors. The present report describes nine cases of small intestinal stromal tumors with eosinophilic stromal globules composed of tangles of curved fibers with crossbands simulating an appearance of skeins, designated as skeinoid fibers. Patients' ages ranged from 28 to 87 years; and four were male. The tumors presented as well-delineated mural nodules ranging from 1.8 to 13 cm in size, causing intestinal obstruction or hemorrhage. Four were in the duodenum, three in the jejunum, and two unspecified. Microscopically, seven were benign; one, to the largest, was definitely malignant and metastasized to the liver. Another, the second largest (7.5 cm), showed moderate atypia with two mitoses per 10 high-power fields. The light microscopic appearance, including immunohistochemistry, were typical for small intestinal stromal tumors. Skeinoid fibers were strongly periodate-Schiff's procedure-positive and stained blue with the trichrome stain. They appeared as a few micra-sized specks to large globules reaching a few millimeters. Skeinoid fibers were also found in three neurogenic spindle cell tumors (an acoustic neuroma, a neurofibroma, and a plexosarcoma of the mesentery), suggesting that such fibers are possible ultrastructural markers for neurogenic tumors and thus small intestinal stromal tumors with skeinoid fibers are neurogenic in origin.

Exocrine pancreatic insufficiency and pancreatic fibrosis due to duodenal somatostatinoma in a patient with neurofibromatosis

A case of duodenal somatostatinoma is described in a patient with Von Recklinghausen neurofibromatosis. The patient presented with exocrine pancreatic insufficiency, probably due to distal obstruction of the pancreatic duct by the tumor. Preoperative evaluation with calcium-pentagastrin and tolbutamide stimulation tests were nondiagnostic. At laparotomy, local excision of the tumor was performed. Pathological findings were compatible with duodenal somatostatinoma, causing pancreatic fibrosis. Somatostatin extracted from the tumor coeluted with the somatostatin-14 standard on high performance liquid chromatography (HPLC).

von Recklinghausen's disease associated with somatostatin-rich duodenal carcinoid (somatostatinoma), medullary thyroid carcinoma and diffuse adrenal medullary hyperplasia

This report describes the concomitant occurrence of a somatostatin-rich duodenal carcinoid, a medullary thyroid carcinoma and a diffuse adrenal medullary hyperplasia in a patient with von Recklinghausen's disease. A 50-year-old Japanese man died from lung metastasis of a malignant schwannoma. In addition to extensive viscero-cutaneous neurofibromatosis, two different types of neuroendocrine tumors were found in the duodenum and thyroid gland at autopsy. The duodenal tumor, which was located in the second portion, showed the histologic appearance of a carcinoid tumor with glandular differentiation and psammoma-bodies. Immunohistochemically the tumor cells were intensely positive for somatostatin. The thyroid tumor was composed of nests of tumor cells arranged in an endocrine pattern, and showed immunoreactivity for calcitonin. A review of the literature revealed no previously reported case of concomitant occurrence of duodenal somatostatinoma and medullary thyroid carcinoma in a single patient with von Recklinghausen's disease. Morphometric analysis of adrenal glands disclosed the presence of diffuse medullary hyperplasia. Thus, the present case exhibited a similarity in some respects with multiple endocrine neoplasia (MEN) syndrome, Type IIa or IIb.