Photoletter to the editor: Proliferating pilomatricoma with no recurrence during a 3-year follow-up

Abstract

Proliferating pilomatricoma is a proliferative variant of pilomatricoma. Although it is considered as a benign tumor, local recurrence may occur. We report a case of a 49-year-old Japanese man with 3-year history of an asymptomatic subcutaneous tumor in the nuchal area. Histological evaluation demonstrated a cystic lesion lined by a basaloid epithelium at the periphery and filled with eosinophilic cornified material containing shadow cells in upper part of the tumor, and multilobular proliferation of basaloid cells in association with small foci of shadow cells in the remaining part. Based on these findings, the diagnosis of proliferating pilomatricoma was made. No recurrence has been observed during a 3-year follow-up.

Keywords: basaloid cells; nuchal area; pilomatricoma; pilomatrix carcinoma; scalp; shadow cells; tumor.

Figure 1

A nuchal subcutaneous tumor: a painless, domeshaped, 45-mm nodule with a normal overlying epidermis.

Figure 2

The upper part of the tumor showed typical fin­dings of classical pilo­ma­tri­co­ma: cystic lesion lined by a basa­loid epithe­lium at the periphery filled with eosino­philic cornified mate­rial containing shadow cells.

Figure 3

In middle to lower part, multiple lobular basaloid proliferation in association with adjacent focal areas containing cornified material and shadow cells with fibrotic stroma.