Large B - Cell Lymphoma of the Leg - Unfavourable Course with Rituximab/Bendamustin.

Background: Cutaneous B-cell lymphomas represent about 25% of all cutaneous lymphomas. Peripheral diffuse large B-cell lymphoma of the leg type is the most aggressive subtype seen mainly in elderly patients. Treatment is not standardised.

Case Report: An 87-year-old female patient was presented in May 2018 because of the development of painless subcutaneous nodules on the legs since late 2017. On examination, we observed up to 5 cm large erythematous nodules on the legs and a smaller plaque in the left submammary fold. The histology of a skin demonstrated tumour infiltrate that was separated from the overlying epidermis by a grenz zone. It consisted of densely packed, blastoid lymphocytic cells with numerous, and some atypical mitoses. The cells were positive for CD20, CD79A and CD5. Almost 100% of the cells were labelled with Ki67. The diagnosis of a diffuse large B-cell lymphoma (PCLBCL-LT) of the leg was confirmed. Histologic analysis of a bone marrow biopsy demonstrated a hypercellular bone marrow without malignant lymphatic infiltrates. Diagnostic ultrasound of cervical nodes and computerised tomography (CT) scans (native and with contrast medium) of head, neck and trunk excluded an extracutaneous manifestation of the PCLBCL-LT. Treatment with rituximab plus bendamustibe was initiated, but tumour progress was noted after the second course. Suggested palliative therapy with radiation and rituximab was refused. The patient died 7 months after diagnosis.

Conclusions: Although some trials suggested a beneficial effect of immuno-chemotherapy, the prognosis of (PCLBCL-LT) remains poor. Standardised treatment is missing due to the relative rarity of this malignancy.