A Case of Nonfunctioning Pancreatic Endocrine Tumor with Atypical Imaging Findings due to Prominent Fibrosis of the Tumor Stroma

• Published in: Journal of Nippon Medical School Vol. 81; no. 3; pp. 179 - 185
• Main Authors: Hoshino, Arichika, Aimoto, Takayuki, Suzuki, Hideyuki, Mizutani, Satoshi, Ishii, Hideaki, Mishima, Keisuke, Wada, Yudai, Kuroda, Seiji, Yagi, Aki, Shimizu, Takao, Oyama, Rina, Yamagiwa, Ryo, Satoh, Seiichi, Oba, Hidemi, Shibuya, Tetsuo, Uchida, Eiji
• Format: Journal Article
• Language: English
• Published: Japan The Medical Association of Nippon Medical School 2014
• Subjects: Biomarkers, Tumor - metabolism; CD56 Antigen - metabolism; Chromogranin A - metabolism; desmoplastic stroma; Diagnostic Imaging - methods; Female; Fibroblasts - metabolism; Fibroblasts - pathology; Fibrosis; Gelatinases - metabolism; Humans; Immunohistochemistry; Membrane Proteins - metabolism; Middle Aged; Pancreas - metabolism; Pancreas - pathology; Pancreas - surgery; pancreatic endocrine tumor; Pancreatic Neoplasms - diagnosis; Pancreatic Neoplasms - metabolism; Pancreatic Neoplasms - surgery; Pancreaticoduodenectomy - methods; Phosphopyruvate Hydratase - metabolism; Serine Endopeptidases - metabolism; Thrombospondins - metabolism; tumor-associated fibroblasts
• ISSN: 1345-4676; 1347-3409
• DOI: 10.1272/jnms.81.179

The patient, a 56-year-old woman, was found during routine checkup to have a disorder of hepatic function. Abdominal ultrasonography showed an ill-defined hypoechoic mass in the head and body of the pancreas; however, no blood-flow signal was observed within the tumor on Doppler ultrasonography. Abdominal computed tomography showed a low-density area in the arterial and portal venous phases. The lesion was visualized as an area of low signal intensity on both T1- and T2-weighted magnetic resonance images, whereas fluorodeoxyglucose positron emission tomography showed fluorodeoxyglucose accumulation in the tumor. Although a preoperative diagnosis was difficult to make, a rapid cytologic examination revealed evidence of a pancreatic endocrine tumor, and subtotal stomach-preserving pancreaticoduodenectomy with portal vein resection was performed. Histopathological examination showed tumor cell nests scattered in abundant fibrotic tissue; the tumor cells had proliferated in a cord-like fashion and showed immunostaining for chromogranin A. Staining for fibroblast activation protein α was seen in the fibroblastic cells contained within the fibrous stroma surrounding the tumor cell nests, whereas both the fibroblastic cells in the tumor and those in the stroma showed a high rate of staining for thrombospondin. We presume that tumor-associated fibroblasts were involved in the fibrosis of the tumor stroma.