Pilomatrixoma and pilomatrix carcinoma deceptively similar but distinct entities.

Pilomatrix carcinoma is a skin tumour about which there is a relative paucity of material in the plastic surgical literature. In the course of their practice most plastic surgeons will have come across the benign skin lesion designated "Clacifying Epithelioma o Malherbe" named thus in recognition of Malherbe\'s description of the entity in I 880, even though erroneously ascribed the tissue of origin to be the sebaceous gland’. Forbis and Helwig in 1961 reviewed 228 such tumours, demonstrated the tissue of origin to be the hair matrix and proposed the term “pilomatrixoma” as more representative of the lesion . These are rare benign skin neoplasms with an incidence rate that varies from 1 in 924 dermatopathologic specimens to I in 2200 surgical pathologic specimens. They are slow growing, typically stony hard dermal nodules, usually less than 3 cm. in size and are most commonly found on the head and neck. They tend to occur in children and teenagers, with a slight female preponderance Taffe et al 3 and more recently Kaddu et al have however documented a second peak of onset in the middle aged and elderly. Radiological examination classically shows a solitary, sharply demarcated subcutaneous tumour with extensive sandlike or dense calcification Histologically they are composed of nests of basaloid cells which undergo abrupt keratinization forming ghost or shadow cells in a background of inflammatory ce Is and calcification. The recommended treatment is excision which is usually a simple matter as the lesion is well circumscribed. Recurrence is rare 2 but has been documented. Though the term ‘giant calcifying epithel ioma” had been coined to denote a tumour that behaved aggressively and recurred, it was not until 1980 when Lopansri and M ihrn flrst used the term “pi lomatrix carcinoma” to describe a recurrent lesion with certain distinctive histological features8. Since then there have been occasional reports in the literature but it remains a rare tumour with less than 30 cases reported till 1994.