Primary Clear Cell Microcystic Adenoma of the Sinonasal Cavity: Pathological or Fortuitous Association?

Primary clear cell microcystic adenoma of the sinonasal cavity is rare. It has previously been described only as a VHL-associated tumour. Von Hippel-Lindau (VHL) syndrome is an inherited cancer syndrome characterised by an elevated risk of neoplasia including clear cell renal cell carcinoma (ccRCC), haemangioblastoma, and phaeochromocytoma. We describe the second reported case of a primary clear cell microcystic adenoma of the sinonasal cavity. The 39-year-old patient with VHL syndrome had previously undergone resection and ablation of ccRCC. He presented with epistaxis. Imaging demonstrated a mass in the ethmoid sinus. Initial clinical suspicion was of metastatic ccRCC. However, tumour morphology and immunoprofile were distinct from the previous ccRCC and supported a diagnosis of primary microcystic adenoma. Analysis of DNA extracted from sinonasal tumour tissue did not show loss of the wild-type allele at the VHL locus. Although this did not support tumour association with VHL disease, it was not possible to look for a loss-of-function mutation. The association of primary microcystic adenoma of the sinonasal cavity with VHL disease remains speculative. These lesions are benign but are likely to require regular surveillance. Such tumours may require repeated surgical excision.

Unique Presentation of Giant Metastatic Microcystic Serous Adenocarcinoma of the Pancreas

Tumors of the pancreas that contain substantial cystic components include mainly mucinous cystic neoplasm, intraductal papillary mucinous neoplasm, solid pseudopapillary tumor, and cystadenomas (which encompass microcystic, macrocystic/oligocystic, and rare solid serous adenomas). Microcystic adenoma of the pancreas is a tumor that is benign in nature. Malignant transformation in the tumor with metastases is rare and only about 26 cases have been reported so far. Here we present a giant microcystic adenoma of the pancreas, possibly the largest ever malignant type in this group ever reported in the literature with extensive metastases to the liver and causing extensive compression and encasement on surrounding structures.