Primary Cutaneous Anaplastic Large Cell Lymphoma (PC-ALCL) is a rare Non-Hodgkin lymphoma (NHL) representing approximately 9% of all cutaneous lymphomas. It usually manifests as a slow-growing, solitary tumor which has a tendency to regress spontaneously. However, metastasis is reported in 5-10% of cases.
Our case is an 81-year-old female with a four-month history of an enlarging nodule on the left upper back. The initial impression was a malignant cutaneous tumor. Histopathology revealed epidermotropic large atypical lymphocytes and diffuse infiltrates of hyperchromatic, pleomorphic mononuclear cells and lymphocytes. Immunohistochemistry showed CD3+, CD20-, CD30+, epithelial membrane antigen (EMA)- and anaplastic lymphoma kinase (ALK)- consistent with PC-ALCL. Metastatic work-up revealed pulmonary involvement. The patient underwent two cycles of multi-agent chemotherapy with marked improvement. However, patient declined further treatment and expired five months after the diagnosis.
This case emphasizes that although PC-ALCL commonly presents with an indolent course, extracutaneous spread can occur. Prompt treatment with chemotherapy increases survival significantly with a cure rate of 92%.