Primary cutaneous CD30+ anaplastic large cell lymphoma: report of a rare case.

Primary cutaneous anaplastic large cell lymphoma (PCALCL) is a rare type of non-Hodgkin's lymphoma comprising approximately 0.9-9.0% of all cutaneous lymphomas. PCALCL is characterized by the absence of systemic involvement, spontaneous regression and low recurrence rate especially in localized lesions.We present a 47-year-old female with a 1½-year history of two asymptomatic erythematous indurated plaques on the right arm. Skin punch biopsy revealed dense infiltrates of non-epidermotropic, large, irregularly-shaped lymphocytes with hyperchromatic and pyknotic nuclei. Immunohistochemistry revealed that these atypical cells are anaplastic lymphoma kinase (ALK) positive, CD30+, CD3-, CD20- and epithelial membrane antigen (EMA) negative. Clinical, histopathological and immunohistochemical findings are consistent with PCALCL. Work-ups revealed no systemic involvement. Short course CHOP (Cyclophosphamide, Doxorubicin, Vincristine, and Prednisone) chemotherapy resulted in total resolution of skin lesions; however, recurrence was noted 12 months after treatment. She then underwent radiotherapy and achieved complete remission.Because the clinical presentation of PCALCL can be variable, a high index of suspicion is necessary in patients presenting with chronic plaques and nodules unresponsive to topical or oral medications.