Cerebellar metastasis of unknown primary neuroendocrine carcinoma: report of a case mimicking hemangioblastoma

Background Neuroendocrine carcinoma (NEC) originates with neuroendocrine cells and is mainly found in the pancreas, lungs and gastrointestinal tract. We surgically treated a case of primary unknown NEC with only cerebral metastasis that mimicked hemangioblastoma. Recurrence was seen at the fornix, and no primary lesion had been identified as of 2 years after treatments despite careful examination. Case Description A 61-year-old man presented with dizziness. Past medical history included hypertension, dyslipidemia, hyperuricemia and colon polyp. We performed magnetic resonance imaging (MRI) to examine the cause of dizziness, revealing tumor with enhancement and peritumoral edema at the right cerebral lesion. Contrast-enhanced whole-body computed tomography (CT) showed no other lesions. We suspected hemangioblastoma from examinations and decided on surgical resection. Neuropathologically, the resected tumor was diagnosed as brain metastasis of NEC, but CT, fluorodeoxyglucose-positron emission tomography, gastrointestinal endoscopy, and somatostatin receptor scintigraphy all failed to reveal the primary lesion. As postoperative MRI showed enhancement around the resection cavity and at the right fornix, radiotherapy was performed. No other lesions were seen at 24 months postoperatively. We are continuing careful monitoring and no chemotherapy has been administered. Conclusions We treated brain metastasis from NEC of unknown primary and mimicking hemangioblastoma using only local treatment. When an enhancing, single, solid tumor is seen in the cerebellum, brain metastasis from NEC of unknown primary is 1 differential diagnosis.