Tahseen M. M. Al Omoush
Mùtah University, Jordan
Title: Melanocytic Hyperplasia in the Epidermis Overlying Trichoblastomas in 100 Randomly Selected Cases
Biography
Biography: Tahseen M. M. Al Omoush
Abstract
Abstract: One hundred cases of trichoblastomas (large nodular, small nodular, cribriform, lymphadenoma, and columnar) were randomly selected and studied for the presence of melanocytic
hyperplasia in the epidermis overlying the tumors, which was defined as foci of increased melanocytes in the basal layer of the epidermis (more than 1 per 4 basal keratinocytes). Focal melanocytic hyperplasia was detected in a total of 22 cases of trichoblastoma
(22%), and this phenomenon was most frequently seen in columnar trichoblastoma (7 cases), followed by large nodular trichoblastoma (5 cases). The mechanism of epidermal melanocytic
hyperplasia overlying trichoblastoma is unclear. Ultraviolet may be a contributing factor, as focal melanocytic hyperplasia was also detected in one-third of cases in the epidermis overlying uninvolved skin, usually associated with solar elastosis. This is further corroborated by the occurrence of the lesions predominantly on the face. Melanocytic hyperplasia overlying trichoblastoma appears to have no impact on the clinical appearance of the lesion and is recognized only microscopically. In an adequate biopsy specimen containing at least part of trichoblastoma, it should not cause any diagnostic problems.
Key Words: melanocytic hyperplasia, trichoblastoma, adnexal tumors, collision, trichoepithelioma