Exogenous trauma simulating perifollicular fibromas.

The patient is a 63-year-old woman who presented to her dermatologist for the removal of two nevi near her mouth. Histologic examination revealed melanocytic nevi showing maturation with dermal descent. Within the dermis, adjacent to these nevoid cells, were multiple large hair follicles that were surrounded by dense fibrosis. The fibrous sheaths contained thickened, dense collagen bundles and were well circumscribed, resembling perifollicular fibromas. Further discussion with the patient and the dermatologist revealed that the patient had "plucked" hair from these nevi. We, therefore, believe that the perifollicular fibrosis that we observed is secondary to trauma. We present this case to remind all that post-traumatic events can simulate perifollicular fibromas and that the erroneous diagnosis of such could lead to the erroneous diagnosis of Birt-Hoggs Dubé syndrome.