TEACHING POINTS

  • Primary cutaneous diffuse large B-cell lymphoma, leg type, is an extranodal lymphoma that manifests as painless red or bluish nodules on the lower extremities.
  • Prognosis is poor, especially if multiple nodules are present at diagnosis, and relapse is common.
  • Treatment consists of anthracycline-based chemotherapy with rituximab, with or without radiation.

CASE

An 80-year-old white woman with hypertension and hypothyroidism presents to the dermatologist for a persistent swollen lesion on her left big toe. Five months before her visit, she had dropped a bottle of ice water on her toe. Painless swelling and erythema developed in the toe soon after, and the swelling slowly progressed in size. Approximately 6 weeks later, she presented to an orthopedist. Radiographs were negative for fracture. She was treated with nonsteroidal anti-inflammatory drugs (NSAIDs) and oral antibiotics, but the lesion did not improve. She then visited a podiatrist, who removed the toenail (Figure 1).

A punch biopsy from the left toe lesion was obtained. The pathology showed a CD20+ dense dermal lymphoid infiltrate. Immunohistochemical stains were positive for Mum1, bcl-2, and FOXP1, consistent with primary cutaneous diffuse large B-cell lymphoma, leg type. The patient was referred to an oncologist. PET scan showed hypermetabolism in the left big toe and left second toe only (Figure 2).

The patient was treated with four cycles of rituximab, etoposide, prednisone, Oncovin, cyclophosphamide, and doxorubicin (R-EPOCH) followed by radiation therapy. She had a complete response and had no signs of recurrent disease 3 months after completing radiation therapy (Figure 3).