Abstract

Hydroa Vacciniforme lymphoproliferative disorder (HV-LPD) is a chronic EBV-positive skin disease with a risk of progression to systemic lymphoma. We report a case of a 12-year-old with a two-year history of multiple recurrent papules and cyclic fever with several preceding skin biopsies. On the recent examination, she presented with erythematous papules that developed central necrotic crusts with scattered pustules and vesicles on the forehead, cheeks, and chin. She had positive EBV serologic studies, and a biopsy demonstrated a dense and diffuse proliferation of small and medium-sized lymphocytes within the dermis extending into the subcutis. Atypical lymphocytes had enlarged nuclei and irregular contours. There were scattered histiocytes and rare eosinophils. The overlying epidermis was hyperplastic with parakeratosis and focal ulceration. By immunohistochemistry, the atypical cells were immunoreactive for CD3, CD43 and CD7. EBER in situ hybridization was positive, and Ki-67 proliferative index was elevated at 60-70%. There was no reactivity for CD4, CD8, CD5, CD30, CD20, CD56 and PD1. These findings were consistent with an NK-cell type of hydroa vacciniforme that likely developed in the setting of chronic persistent EBV-associated hypersensitivity to mosquito bites. Hydroa vacciniforme-like lymphoproliferative disorder is driven by chronic active severe EBV infection resulting in a proliferation of T-cells or NK-cells. It is endemic to the Asia and indigenous populations of South and Central America and is rarely seen in the US. This case highlights the challenges of the histopathologic work-up of an NK variant of hydroa vacciniforme.