Apocrine hidrocystoma arising from a nevus sebaceous: A case report

Apocrine hidrocystoma (AHC) are benign adnexal cystic tumours of the skin. They are uncommon and are usually found in the head and neck area. Nevus sebaceous (NS) is a hamartoma which is present since birth and is associated with many benign and malignant tumours such as trichoblastoma, trichilemmoma, sebaceoma, nevocellular nevi, keratoacanthoma, basal cell carcinoma etc. Apocrine hidrocystoma arising from a nevus sebaceous located over scalp region is extremely rare with less than five cases being reported till date. We report an interesting case of a 55 year old male who presented with a nodule over the scalp. A clinical diagnosis of sebaceous cyst was made. On histopathological examination, it turned out to be apocrine hidrocystoma arising in the background of nevus sebaceous.