Turkish Journal of Pathology

Türk Patoloji Dergisi

Turkish Journal of Pathology

Ankara Patoloji Bülteni Archive

2001, Vol 18, Num, 2     (Pages: 023-027)

Pilomatrixoma: (Developmental stage - proliferating and malignant pilomatrixoma: 292 cases)

Taner Akalın, Ali Veral, Murat Sezak, Gülşen Kandiloğlu

Ege Üniversitesi Tıp Fakültesi Patoloji Anabilim Dalı, İZMİR

Pilomatrixoma is a benign skin adnexal tumor, characterized by basaloid cells which represent differentiation toward hair matrix and shadow cells. The number of large series in which demographic data is given, is not too much. In this report, the findings of 299 pilomatrixomas belonging to 291 cases and one malignant pilomatrixoma case were given. The femalet to male ratio was 1,8/1, the mean of age was 27,3 (1-75). Fifty two percent of cases were involved in the first two decades and fifty percent of cases were located on the head and neck.

Histologically, cases were divided into four stages. Of the cases, 35 were (12%) early lesions or fully developed pilomatrixomas which have no regression findings. Early regression findings were seen in 140 (47%) cases. Of the cases, 124 were (41%) in the late regression stage in which epithelial structures were not present. These findings support the idea that in pilomatrixomas, regression begin in an early period and it follows a chronological process. Eight cases were called as proliferating pilomatrixoma which was characterized by lobular growth pattem and solid basaloid cell proliferation areas. Proliferating pilomatrixoma cases were older, bigger in terms of tumor size, higher in terms of mitotic activity than conventional pilomatrixoma. Disorder of large tumor islands, presence of small islands and infiltrative growth pattern, presence of shadow cells in a very limited areas and cellular atypia were the histologic findings that favor malignant pilomatrixoma.

Keywords : Pilomatriksoma, malign pilomatriksoma, progresyon,