Mucoepidermoid carcinoma ex-inverted papilloma.

Mucoepidermoid carcinoma (MEC) typically arises from major salivary glands, minor salivary glands of the oral cavity and mucous glands of the aerodigestive tract. Cases of MEC arising from benign sinonasal or lacrimal papillomas are extremely rare. Herein we describe a MEC representing malignant transformation of an inverted Schneiderian papilloma. The patient presented with nasal bridge pain radiating to the premaxillary regions. Imaging showed a tumour involving the left nasal cavity, left ethmoid and maxillary sinuses and extending into the left orbit and lacrimal sac. Initial biopsy and debulking specimens showed only inverted papilloma. The re-excision specimen demonstrated a tumour with features of both inverted papilloma and MEC that superficially invaded bone. The tumour was negative for MECT1-MAML2 translocation. Linear array analysis of tumour tissue demonstrated the presence of human papillomavirus-11 (HPV-11). [ABSTRACT FROM AUTHOR]