Nonfunctional Islet Cell Tumor of the Pancreas in a Patient with Tuberous Sclerosis: A Case Report with Literature Review
A 63-year-old-woman was referred to our department with a complaint of abdominal pain. Upon physical examination, skin lesions were detected and a firm mass was palpable in the upper quadrant of the abdomen. Laboratory findings were unremarkable. She was referred to the radiology department for a computed tomography (CT) examination of the abdomen. A biphasic contrast enhanced CT was also performed on a 16-slice CT system (Somatom Sensation, Siemens, Erlangen, Germany). An intravenous injection of 130 mL contrast media (iopamidol with an iodine concentration of 300 mg/mL) was given at a rate of 4 mL/s. Scanning was initiated after a delay of 25 s and 70 s after infusion of contrast material for the arterial phase and venous phase images, respectively. Scanning parameters were as follows: Slice collimation, 16 × 1.5 mm; table feed/rotation, 18.0 mm; rotation time, 0.5 s; KV 120; effective mAs 160, slice thickness, 2 mm.\nCT examination revealed a 9 × 6 cm mass with discrete nodular calcifications in the head of the pancreas. The mass showed heterogeneous enhancement in the arterial phase and homogenous enhancement in the venous phase [Figure and ]. The gastroduodenal artery was seen encased by the pancreatic mass. There were also multiple lesions in the liver ranging in diameter from 3 to 25 mm. Some of the lesions showed homogenous fat-density; however, others had heterogeneous areas of soft-tissue density and fat-density that were suggestive of AML. Lesions with homogenous fat-density did not show any enhancement in both the arterial and the venous phase images []. In lesions containing both a soft tissue component and a fat component, the nonfat component was enhanced markedly in the arterial phase and showed isohypodensity in the venous phase. Four lesions ranging from 3 to 12 mm in diameter had no fat components. These lesions had homogenous enhancement in the arterial phase image and became isohypodense in the venous phase image []. There were also multiple fat-containing lesions in both kidneys compatible with AML [] as well as multiple small discrete sclerotic lesions in the vertebrae. A cranial CT revealed multiple calcified subependymal nodules []. Unfortunately, as the patient was claustrophobic she did not undergo a magnetic resonance imaging (MRI) investigation.\nThe diagnosis of tuberous sclerosis was established on the basis of radiologic findings of renal and hepatic AML, calcified subependymal nodules, and vertebral sclerotic lesions with a clinical finding of adenoma sebaceum. Ultrasound-guided fine-needle aspiration of the pancreatic mass was performed using a 20-gauge needle. Histological examination of the cell-block preparations of the mass showed solid sheets of neuroendocrine-appearing cells characterized by large eosinophilic cytoplasm with moderate nuclear pleomorphism []. Immunochemical staining showed the cells were positive for synaptophysin and a few tumor cells were positive for chromogranin. On the basis of the morphologic and immunohistochemical findings, the lesion was diagnosed as ICT. Since the patient's serum levels of the pancreatic hormones were within the normal limits, ICT was considered as a nonfunctioning lesion.