Monotypic angiomyolipoma of the nasal cavity: An extremely rare cause of nasal mass with recurrent epistaxis

ABSTRACT

Monotypic angiomyolipoma is usually found in the kidneys and is composed predominantly of epithelioid cells which show positivity for melanocyte and smooth muscle markers. It can pose a diagnostic challenge due to a range of differential diagnosis. We report the second case of monotypic angiomyolipoma of nasal cavity and first from India in a 54-year-old male who presented with a nasal polyp. Grossly the tumor was well circumscribed and un-encapsulated. Microscopy showed a large number of epithelioid cells mixed with a few spindle cells, varying sized blood vessels, and focal areas of adipose tissue. Immunohistochemistry was positive for smooth muscle actin (SMA) and human melanoma black (HMB-45) stains. It is important to identify this tumor as it can sometimes be mistaken for malignancy and only needs endoscopic resection.