Gastrointestinal stromal tumor of the duodenum: a case report

Small Periampullary Duodenal Gastrointestinal Stromal Tumor Treated by Local Excision: Report of a Case

Gastrointestinal stromal tumors (GIST) are mainly located in the stomach and the small bowel, with the duodenum accounting for about 4%. We report the case of a 66-year-old woman with a periampullary GIST of the duodenum that was treated by local excision and direct duodenal wall defect repair. Since no definitive clinical criteria have been established to differentiate malignant from benign mesenchymal tumors, preoperative cytology was not available and surgical removal of the 3.5 cm tumor was feasible, the patient was treated conservatively. The morbidity and mortality rates of the more radical and invasive duodenopancreatectomy, in particular when dealing with a soft pancreatic stump with a narrow pancreatic duct, are, in our opinion, too high for a potentially benign disease when the more conservative procedure is feasible. Four years after surgery the patient is doing well and control CT scan showed the absence of local recurrence.

Gastrointestinal stromal tumor of the ampulla of Vater with osteoclastic giant cells, osteoid-like matrix deposition, and aneurysmal bone cyst-like features

Gastrointestinal stromal tumors are a heterogeneous group with a wide spectrum of histologic features. We describe the first case of 61-year-old woman who presented gastrointestinal stromal tumors of the ampulla of Vater with osteoclast-like giant cells surrounding osteoid-like material and aneurismal bone cyst-like areas. The phenotype was supported by light microscopy and corroborated by immunohistochemistry analysis. Because of the presence of osteoid-like and aneurismal bone cyst-like components, it is first necessary to make differential diagnosis with other entities such as metastatic osteosarcoma. Our case shows another form of differentiation that has not previously been reported.

Immunophenotype, proliferation, DNA ploidy, and biological behavior of gastrointestinal stromal tumors: a multivariate clinicopathologic study

To determine the prognostic impact of clinical, immunohistochemical, and biological parameters, we examined 52 gastrointestinal stromal tumors (GIST) by conventional light microscopy and immunohistochemistry. DNA ploidy was analyzed by image cytometry on cytospin preparation. The proliferative activity was determined by mitosis counting and assessment of Ki-67 reactivity by means of monoclonal antibody Ki-S5. A histopathologic grade was assigned to each tumor according to the French Federation of Cancer Centers (FNCLCC) grading system. Next to vimentin, CD34 was the most prevalent antigen, followed by markers of neural and muscular differentiation. Many tumors exhibited a mixed phenotype. Twenty-one tumors were diploid, eight hypodiploid, and 23 aneuploid. In univariate analysis, tumor grade, Ki-S5 labeling index, mitotic count, atypical mitoses, cellularity, and sex were predictive of both mortality and metastasis risk. DNA ploidy only correlated with overall survival, whereas the tumor location affected the occurrence of metastases. Multivariate analysis selected Ki-S5 scores (P < .0001) and atypical mitoses (P=.012) as independent prognosticators for overall survival, and tumor grade (P=.0036) and size (P=.0055) as predictors of metastatic spread. We conclude that GIST are primitive mesenchymal tumors capable of divergent differentiation, which does not influence their prognosis. The latter appears to be best predicted by histopathologic grading and the Ki-67 labeling index.

Metastasis in a benign duodenal stromal tumour

Gastro-intestinal stromal tumour (GIST) is increasingly recognized as a distinct entity within the group of soft tissue tumours. Mostly, GIST arises from the muscular components of the stromal layer, but the tumour may also originate from the autonomic nerve system, recently designated as gastro-intestinal autonomic nerve tumour (GANT). The majority of GIST is located in the stomach and small intestine; only 4% of GIST is found in the duodenum. Clinical and pathological criteria to differentiate benign from malignant GIST are not well established. Tumour size and mitotic activity are commonly considered as important features, predicting biological behaviour and outcome. It has been suggested that the clinical course of the GANT-type tumours may be more aggressive. We present a case of a radically resected duodenal stromal tumour with benign features, in a young woman, with metastases to the liver and peritoneum occurring 8 years after the initial diagnosis.

Gastrointestinal autonomic nerve tumor: further observations regarding an ultrastructural and immunohistochemical analysis of six cases

Gastrointestinal autonomic nerve tumor (GANT) is a specialized form of stromal neoplasm whose ultrastructural features support a myenteric plexus derivation and provide the basis for its diagnosis. GANT actual frequency, relationship to skeinoid fibers, and CD34 expression status are some of the controversial aspects of this entity. Out of 14 gastrointestinal stromal tumors gathered during a 1-year period, six (42%) instances were diagnosed as GANT by electron microscopic study of at least five ultrathin sections per case. Additionally, GANTs were immunohistochemically investigated with a panel of nine antibodies including CD34. Ultrastructurally, every GANT case showed diagnostic findings and evidence of skeinoid fibers, whereas immunohistochemically all except one were CD34 positive. Immunoreactivity for neuron-specific enolase, synaptophysin, and vimentin was a common occurrence as well. In conclusion, GANT seems to be more frequent than hitherto recognized, skenoid fibers are a regular feature of GANT, and a positive CD34 immunoreaction does not discriminate between GANT and other non-smooth muscle, non-schwannian neoplasms.

Subclassification of gastrointestinal stromal tumors based on evaluation by electron microscopy and immunohistochemistry

Fifty-six gastrointestinal stromal tumors (GIST) were subclassified by ultrastructural examination and by immunophenotypic analysis using a panel of 13 antibodies. Eighty percent of the tumors originated in the stomach and small intestines. The neoplasms were classified as follows: 42.9% smooth muscle tumors (4 leiomyomas, 9 spindle cell and 8 epithelioid leiomyosarcomas, and 3 mixed spindle cell and epithelioid leiomyosarcomas); 37.5% gastrointestinal autonomic nerve tumors (GANT), 47.6% of which arose in the small intestines; 8.9% mixed leiomyosarcoma/neurogenic tumors; and 10.7% undifferentiated GIST, not otherwise specified. The muscle common actin antibody HHF-35, variably reactive with tumor cells composing 23 of 24 smooth muscle tumors, was found to be the most sensitive marker of leiomyocyte differentiation. One immunophenotypically questionable spindle cell leiomyosarcoma was diagnosed by electron microscopy. Since neuron specific enolase positive cells were found in 1/3 of the leiomyosarcoma cases, the ultrastructural demonstration of synapse-like structures and neurosecretory granules was required for diagnosing GANTs. The immunophenotype of the ultrastructurally undifferentiated GIST was vimentin and CD34+. Variable numbers of ultrastructurally undifferentiated cells also we found in all of the tumors except 2 leiomyomas. CD34 was also expressed in smooth muscle (54%) and GAN (62%) tumors. Despite their similar light microscopic appearance, GIST are phenotypically heterogeneous, requiring both ultrastructural and immunohistochemical studies for accurate characterization.