Facial Presentation of Primary Cutaneous Diffuse Large B-Cell Lymphoma, Leg Type: A Rare Case.

An elderly woman presented with a solitary ulcerated facial lesion, which raised concern for various diagnoses, including squamous cell carcinoma, melanoma, basal cell carcinoma, or an infection. Given the lesion's unusual location, a skin biopsy was performed, and immunohistochemical analysis confirmed the diagnosis of primary cutaneous diffuse large B-cell lymphoma, leg type (PCDLBCL-LT). PCDLBCL-LT is a rare, aggressive form of lymphoma that typically manifests on the legs but can, as in this case, present in atypical sites such as the face. She was treated with a combination of rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP) chemotherapy and radiation therapy, leading to a complete remission. Remarkably, after nearly 10 years, there has been no recurrence of the disease. This case highlights the importance of considering cutaneous lymphoma in the differential diagnosis for isolated, ulcerated skin lesions, even when they appear in uncommon locations, and emphasizes the potential for successful outcomes with early and appropriate treatment.