Tubulopapillary Hidradenoma-like Tumour of the Mandible: A Case Report and Literature Review.

Tubulopapillary hidradenoma is an uncommon benign sweat gland tumour which appears as a well-defined superficially located dermal nodule, most commonly occurring in the head or of the extremities. Its occurrence is extremely rare in the mandible, as there are only two cases of tubulopapillary hidradenoma-like tumour of the mandiblereported in the literature. Microscopically, the lesion appears as a well circumscribed but unencapsulated neoplasm composed of numerous irregularly shaped tubular structures that have a double to several layered epithelial lining. The outer layer consists of flat to cuboidal myoepithelial cells and inner layer contains cuboidal to columnar cells that demonstrate decapitation secretions. We report an unusual case of tubulopapillary hidradenoma-like tumour presented as a nodular growth in the right retromolar region of the mandible in a 67-year-old man. The light microscopic features along with immunohistochemical findings of this unusual neoplasm are discussed.