Expanding phenotypic spectrum of familial comedones.

Familial comedones is a rare autosomal dominant disorder characterized by thousands of comedones developing in teens. Some pits or inflammatory lesions may coexist. Only 32 patients from three families have previously been reported. We report herein 12 cases in two unrelated families with familial comedones. Clinical manifestations among members in the same family vastly vary from scattered comedones on the face, trunk, upper and lower extremities to generalized thousands of open comedones, a large number of skin pits and acneiform inflammatory lesions over the entire body. Additionally, multiple severe purulent nodules and abscesses that leave unsightly scars similar to those of hidradenitis suppurativa are observed. Lesions of long-standing inflammation in two patients had developed into squamous cell carcinoma with a poor prognosis. The phenotypic spectrum of familial comedones varies to a large degree. Most importantly, there is potential for some long-standing inflammatory lesions to develop into squamous cell carcinoma. Extra vigilance in surveillance and prompt treatment for such lesions are recommended.