Pilomatricoma is a rare benign follicular tumor in Asians

purpose of this study was to assess the clinical and histopathological features of the tumor.

The hospital charts and slides of 13 patients with pilomatricoma over a 12-year period at Ewha Womans University Tongdaemun Hospital were retrospectively reviewed.

The age of patients ranged from 5 to 76 years with a mean of 21.5 years. The maleto-female ratio was 1:3.3. Seventy-seven percent of the tumors were located on the upper and lower extremities, followed by the face and neck. Most tumors appeared as a pea-sized hard movable skin-colored nodule. At histopathologic level, the most common morphological stage was the early regressive stage (stage 3), followed by late regressive (stage 4), fully developed (stage 2), and early (stage 1) stages. Foreign body giant cells, calci6cation, ossification were seen in 69.2%, 84.6%, and 7.7%, respectively; giant cells and inflammatory infiltrate were mostly seen in stage 3 tumors, calcification in stage 3 and 4 tumors, and ossification, only in the sole stage 4 tumor. Anetodermic changes of overlying dermis were seen in 2 cases (15.4%).

The various histopathologic features of pilomatricoma can be explained by its chronological, morphological stages.Most pilomatricomas present for longer than 6 months are already in stage 3, and one can expect the histopathological features accordingly.