Abstract

A 65-year-old man who had undergone a renal transplant seven years prior presented with a one-month history of a pruritic rash involving the back, forearms, and legs. The patient was receiving oral immunosuppression with tacrolimus, mycophenolate, and prednisone. Physical examination revealed a diffuse eruption of varying morphologies with faint annular erythematous patches, hyperpigmented lichenified plaques, and verrucous dark-brown papules. Punch biopsies from the left thigh demonstrated the distinctive finding of dyskeratosis with tiered parakeratosis. The expanded basket weave stratum corneum contained clusters of eosinophilic nucleated viropathic keratinocytes, reminiscent of peacock feathers. In the clinical setting of chronic immunosuppression, the histologic findings were consistent with human polyomavirus-6 (HPyV6) and human polyomavirus-7 (HPyV7) associated rash and pruritus (PVARP). Antiviral therapy was initiated with topical cidofivir and oral valganciclovir. At 3 months follow-up, the patient was noted to have disease progression with no response to treatment. His immunosuppression has since been lowered.  PVARP, also known as polyomavirus associated pruritic and dyskeratotic dermatosis (PDD), is a rare, chronic, epidermal viral skin infection primarily affecting immunocompromised patients. It is thus far reported in association with HPyV6 and HPyV7. PVARP is challenging to manage given the difficulty in establishing a diagnosis and the ongoing need to continue immunosuppression therapy in affected patients. We present this interesting case to increase awareness of the subtle but distinctive “peacock plumage” histologic pattern that leads to the diagnosis of this rare disease. Increased identification of the disease will aid in its further characterization and development of successful treatment regimens.