Cidofovir gel as treatment of follicular spicules in multiple myeloma.

IMPORTANCE The cause of follicular spicules in multiple myeloma (MM) is not known. OBSERVATIONS We present a case of follicular spicules in a patient with MM, which is very reminiscent of trichodysplasia spinulosa caused by a polyomavirus. No trichodysplasia spinulosa-associated polyomavirus could be isolated from the skin lesions; however, the spicules were positive for Merkel cell carcinoma virus, which is also a polyomavirus. CONCLUSIONS AND RELEVANCE Follicular spicules in MM are probably not caused by the trichodysplasia spinulosa-associated virus. Merkel cell polyomavirus could contribute to the origin of this dermatosis.