Neutrophilic Eccrine Hidradenitis in a Primary CNS Lymphoma Patient Receiving High-Dose Chemotherap

Neutrophilic Eccrine Hidradenitis (NEH) is a rare inflammatory neutrophilic dermatosis that primarily affects eccrine sweat glands. Although it has been described in various malignancies and with therapeutic agents, it is most frequently associated with cytarabine-based induction chemotherapy for acute myelogenous leukemia. We report a rare case of NEH in a 63-year-old male with a medical history significant for primary CNS lymphoma. The patient was treated with high-dose thiotepa, busulfan, and cyclophosphamide (BuCy) followed by autologous stem cell transplantation, which was complicated by bacteremia and septic shock. Approximately three weeks after chemotherapy, he developed localized bright red, desquamating plaques on his bilateral outer hips, posterior upper thighs, and buttocks. Histological findings revealed neutrophils infiltrating and surrounding the eccrine glands accompanied by squamous syringometaplasia, apoptotic keratinocytes, and basovacuolar changes. This case serves to highlight that NEH should be considered in the differential diagnosis of erosive, erythematous plaques, especially in patients with lymphoproliferative tumors receiving high-dose chemotherapy, in order to provide appropriate clinical management.