A dermatological perspective: eosinophilic eruption of hematoproliferative disease as a clinical and histological dilemma.

The emergence of de novo or recurrent cutaneous eruptions in individuals with hematological diseases presents a challenge when determining whether they indicate secondary dissemination or an unrelated diagnosis. Eosinophilic eruption of hematoproliferative disease is a rare nonspecific manifestation accompanying lymphoproliferative disorders, including chronic lymphocytic leukemia (CLL). We present the case of a 70-year-old man with CLL in remission (previously treated with two 6-month cycles of fludarabine-cyclophosphamide plus rituximab, 2 and 5 years earlier) with an acute, disseminated polymorphic skin eruption. Skin biopsies from two sites (bulla and infiltrated nodule) were taken for histopathological examination. The pathologist reported giant spongiform vesicle formation with eosinophils with dermal and hypodermal inflammatory infiltrate composed of lymphocytes (predominantly T cells, fewer B cells) and eosinophils. Secondary neoplasm dissemination and sarcoidosis were excluded by means of immunohistochemistry. A diagnosis of eosinophilic eruption of hematoproliferative disease in the CLL patient post-chemotherapy and without active disease was established. Two weeks after skin remission, the patient worsened with enlarged lymph nodes and a leukocyte count of 291 × 10^9/l. CLL relapse was confirmed. Leukocytapheresis was performed and ibrutinib 140 mg three times daily was prescribed. Our case underscores the importance of recognizing this relatively common but underreported eosinophilic eruption associated with hematoproliferative diseases.