Follicular Porokeratoma: Report of a New Variant of Porokeratoma (Porokeratotic Acanthoma) and Literature Review

Porokeratoma is a rare type of epidermal acanthoma. of which 22 cases have been published in the literature. It is characterized by the presence of multiple cornoid lamellae embedded within a single verrucous or keratotic nodule. Despite this histologic feature being shared with porokeratosis, the etiopathogenesis of porokeratoma and its relationship with porokeratosis remain unclear. We report a new case of porokeratoma involving hair follicles, a finding that has been reported in only one of the previously published cases. Analogous to follicular porokeratosis, a form of porokeratosis involving hair follicles, we have termed this lesion follicular porokeratoma. A review of all 23 published cases (including the present case) is also provided.

Automated summary

Porokeratoma is a rare type of epidermal acanthoma characterized by the presence of cornoid lamellae within a verrucous or keratotic nodule. This study reports a new case of porokeratoma involving hair follicles, which has only been reported in one previous case, and provides a review of all 23 published cases.