Inhibin-expressing clear cell neuroendocrine tumor of the ampulla: an unusual presentation of von Hippel-Lindau disease.

[von hippel-lindau disease]

von Hippel-Lindau (VHL ) disease is a hereditary autosomal dominant disorder associated with deletions or mutations in the VHL tumor suppressor gene . Characteristically , up to 60 Â % of neuroendocrine tumors (NETs ) associated with VHL disease display a spectrum of clear cell morphology including multivacuolated lipid-rich cell change . Unlike neurofibromatosis type 1 and multiple endocrine neoplasia type 1 syndromes , ampullary NETs have not been described in association with VHL disease . In this report , we discuss the features of an incidental ampullary clear cell NET occurring in a patient with pancreatic VHL disease including multiple pancreatic NETs . The ampullary lesion consisted of epithelial cells resembling lipoblasts or signet ring cells . In our case , all NETs showing clear cell change were positive for inhibin . While the underlying mechanism of this finding is largely unknown , it is of note that positivity for inhibin has not been observed in clear cell NETs associated with multiple endocrine neoplasia type 1 syndrome . Our case proves that NETs can develop in the ampullary region in patients with VHL ; clear cell change can occur in these lesions and can mimic signet ring cell carcinoma . This issue is of clinical significance especially in small biopsy samples ; thus , positivity for keratin alone should not be taken as evidence of an adenocarcinoma . Moreover , demonstration of inhibin expression in a NET with clear cell change along with other clinical stigmata should alert the diagnostician to the possibility of VHL disease . However , further larger series examining inhibin expression in both syndrome-related and sporadic clear cell NETs are needed to confirm our findings .

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von hippel-lindau disease

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