Sequential multifocal ocular adnexal recurrence of blastic plasmacytoid dendritic cell neoplasm.

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare and aggressive hematologic malignancy typically involving the skin, bone marrow, and central nervous system. Ocular adnexal involvement is exceedingly rare. We present a novel case of a 74-year-old man with BPDCN in remission following autologous stem cell transplantation who developed sequential ocular adnexal recurrences. He initially presented with a protuberant lesion of the right caruncle, followed by new lesions of the left lacrimal gland and right subconjunctival space. Histopathologic analysis confirmed BPDCN recurrence. Notably, these lesions developed despite ongoing systemic therapy and concurrent improvement of his skin disease. This case expands the known spectrum of extramedullary BPDCN and suggests that adnexal tissues may serve as sanctuary sites for disease relapse. Prompt ophthalmologic evaluation and biopsy of atypical findings in BPDCN patients is critical for early detection and management of recurrence.