The Proliferating and Malignant Proliferating Trichilemmal Cyst: An Anatomo-Clinical Study of Three Cases.

Background: The proliferating and malignant proliferating trichilemmal cysts (MPTC) are rare adnexal tumors. We report 3 cases through which we will detail the anatomo-clinical characteristics of these tumors. Cases: Two patients, 60 and 56 years old, consulted for multiple scalp nodules, one of which had changed with the appearance of a central ulceration. The removal of the remaining scalp nodules was in favor of PTCs. The third patient presented with an ulcerative lesion occupying the vertex. Skin biopsy found trichilemmal-type keratinization associated with areas of necrosis concluding with a MPTC. Discussion: The PTC is a transitional form between the trichilemmal cyst (TC) and the MPTC. The increase in the size of a TC and ulceration are sufficient signals to suspect this evolution.