Proliferating trichilemmal cyst on scalp with local recurrence

Abstract

Among the tumors with trichilemmal or pilar differentiation is the proliferating trichilemmal cyst, which is derived from the external root sheath of the hair follicle and constitutes a rare dermal neoplasm. It usually occurs mainly in women over 50 years of age, mainly on the scalp. Among the tumors with trichilemmal or pilar differentiation is the proliferating trichilemmal cyst, which is derived from the external root sheath of the hair follicle and constitutes a rare dermal neoplasm. It usually occurs mainly in women over 50 years of age, mainly on the scalp. Although their malignancy is rare, they may have locally aggressive behavior and risk of recurrence. They are characterized by slow growth, and histologically a wall of squamous epithelial cysts without a granular layer and lobes or trabeculae of basaloid-like cells with abrupt trichilemmal-type keratinization are observed, which can be associated with necrosis or ulceration. Although their malignancy is rare, they may have locally aggressive behavior and risk of recurrence. They are characterized by slow growth, and histologically a wall of squamous epithelial cysts without a granular layer and lobes or trabeculae of basaloid-like cells with abrupt trichilemmal-type keratinization are observed, which can be associated with necrosis or ulceration. A 58-year-old male patient is presented with a proliferating trichilemmal cyst of the scalp, which presented local recurrence. Taking into account the low incidence of these tumors and their difficult clinical and histological interpretation, it was decided to present the case.