A case of nonfunctioning pancreatic endocrine tumor with atypical imaging findings due to prominent fibrosis of the tumor stroma.
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.
Institute of Gastroenterology, Nippon Medical School Musashi Kosugi Hospital.
Arichika
A
Hoshino
Takayuki
T
Aimoto
Hideyuki
H
Suzuki
Satoshi
S
Mizutani
Yoshiharu
Y
Nakamura
Hideaki
H
Ishii
Seiichi
S
Satoh
Hidemi
H
Oba
Tetsuo
T
Sibuya
Eiji
E
Uchida
D003581:Cytodiagnosis; D038524:Diffusion Magnetic Resonance Imaging; D005260:Female; D005355:Fibrosis; D006801:Humans; D007150:Immunohistochemistry; D008875:Middle Aged; D010190:Pancreatic Neoplasms / Q000175:diagnosis* / Q000473:pathology*; D049268:Positron-Emission Tomography; D014057:Tomography, X-Ray Computed; D018608:Ultrasonography, Doppler