Blastic Plasmacytoid Dendritic Cell Neoplasm Presenting as Fever with Diffuse Cutaneous Nodules

A young man, presented with high-grade fever and disseminated asymptomatic skin lesions of 6-weeks duration. Cutaneous examination revealed multiple infiltrated monomorphic skin-colored papules and nodules upto 2×2 cm all over scalp, face, trunk and extremities. Light microscopy of nodules showed diffuse infiltration of dermis and subcutis by a tumor composed of medium to large cells with round to ovoid nuclei with fine chromatin, few with visible nucleoli and scanty to moderate amounts of eosinophilic cytoplasm. Tumor cells were positive for CD4, CD8, CD56 and negative for CD30, terminal deoxynucleotidyl transferase and Alk-1. Excised axillary lymph node showed similar morphologic and immunohistochemical findings. There was bone marrow involvement with infiltrate of large atypical/immature lymphoid cells. Diagnosis of blastic plasmacytoid dendritic cell neoplasm was made. This is a rare neoplasm. presenting commonly in the skin, with or without concurrent extracutaneous disease.