Malignant Islet Cell Tumor with Sarcomatous Differentiation

Abstract

Malignant mesenchymal neoplasms of the pancreas are rare and malignant islet cell tumors with sarcomatous dedifferentiation are rarer still. We present a case of malignant islet cell tumor with sarcomatous differentiation, which to our knowledge is only the second reported case showing such a combination of morphologic features. Clinically, the neoplasm was not hormonally active and immunohistochemical staining was negative for gastrin, glucagon, insulin and somatostatin. The sarcomatous component strongly reacted with an antibody directed against vimentin, and a minority of cells stained strongly with antisera directed against desmin and smooth muscle actin. Primary sarcomas of the pancreas are rare (1-7), with fewer than a dozen leiomyosarcomas and a single liposarcoma being reported in the English language literature. Rarer still are malignant islet cell tumors with sarcomatous differentiation. Only a single case report of such a combined neoplasm has to our knowledge appeared in the English language literature (8).The histomorphologic spectrum of carcinoid tumors is wide with glandular morphologies, papillary structures, oncocytic changes, squamous and osseous metaplasia and spindle cell patterns being recognized (9 -14). The spindle cell pattern described by Rosai et al. (14) appears to be unrelated to the sarcomatous changes seen in our case and that described by Ferreiro et al. (8). We report a case of pancreatic carcinoid (islet cell tumor) with focal myosarcomatous differentiation, which is to our knowledge only the second such case reported in the English language literature. CASE REPORTThe patient, a 61-year-old Caucasian female, was followed at the University of Utah for gastroesophageal reflux of long duration controlled by Prilosec. An ultrasound of the abdomen was obtained 3 months before admission to investigate the patient's complaint of vague abdominal pain. A lesion was visualized around the liver, and endoscopy was performed, which revealed a Barrett's esophagus without dysplasia. A follow-up CT scan demonstrated a 10 cm heterogenous mass in the tail of the pancreas (Fig. 1) and three lesions in her liver. The patient's clinical history was otherwise unremarkable except for back pain, most noticeable when lying in bed. Physical examination failed to reveal icterus or lymphadenopathy. The patient underwent exploratory laparotomy with intraoperative biopsy and frozen section of the largest of the liver lesions. Frozen section revealed a hemangioma, and the pancreatic mass was then resected. The postoperative course was unremarkable, and no metastatic lesions have been detected in the immediate postoperative period. METHODSRepresentative tissue sections were taken from the specimen, fixed in 10% neutral buffered forma-

A Case of Adult Pancreatoblastoma With Novel APC Mutation and Genetic Heterogeneity

“…It recruits the coactivator b-catenin to enhancer elements of the genes and activates transcription of cyclin D1, c-jun, and c-myc (10), and its expression was observed in all the cell components. The clear cells were morphologically similar to the cells seen in subtypes of neuroendocrine tumor: clear cell type (11,12), spindle cell type (13), and neuroendocrine tumor with sarcomatoid differentiation (14). Immunohistochemical staining showed that the clear cells were positive for chromogranin A, synaptophysin, CD56, NSE, and AE1/AE3, indicating neuroendocrine differentiation of the cells.…”