A 3-year-old girl presented with a severel months history for a pink nodular lesion on her cheek. No pruritus or scaliness was present. The patient had no rash in any other location and no history of recent drug use...

 What is your diagnosis?

Diagnosis: Pilomatricoma

Pilomatricoma or calcifying epithelioma of Malherbe is the commonest hair-follicle tumor and is frequently seen in children. Clinically, pilomatricoma usually presents as a firm, deeply seated nodule that is covered by normal skin, but occasionally it is more superficially located, causing a blue-red discoloration as like as this case. The face and upper extremities are the most common sites. Hardness of the tumor is a good clinical clue for diagnosis.

Histologically, the tumor is composed of two types of cells, basophilic cells and eosinophilic (shadow cells). Eosinophilic foci of keratinization and basophilic deposits of calcifiction are scattered throughout.