[Aggressive primary cutaneous B-cell lymphomas and novel EBV+ entities]

Primary cutaneous large B‑cell lymphomas (PCBLT), EBV-positive large B‑cell lymphomas, not otherwise specified (EBV+ DLBCL, NOS), and primary cutaneous intravascular large B‑cell lymphomas (PCIVLBL) are recognized as cutaneous lymphomas with intermediate to poor prognosis. Differentiation from indolent B‑cell lymphomas or other pathologies of the skin can be complex, both clinically and histologically, but vital for the outcome of the patient. The combination of immunotherapy and polychemotherapy regimens, such as R‑CHOP, has led to significant improvements in prognosis, especially in diffuse large B‑cell lymphomas. Therapeutic decisions need to be individually made for each patient, ideally within an interdisciplinary tumor conference. Immunosenescence may be an important factor in the pathogenesis of EBV+ DLBCL, NOS in elderly individuals. Their prognosis is less favorable than that of patients with EBV-negative PCBLT, whereby this has been observed particularly in elderly patients. One third of patients with PCIVLBL progress to systemic disease. The occurrence of nodal manifestation is rarely observed. Symptoms may vary depending on the organ system involved. Currently there are no evidence-based therapy recommendations due to the rarity of the disease. EBV-positive mucocutaneous ulcer is a new provisional category in the current WHO classification for lymphoid neoplasms. It has been segregated from EBV+ DLBCL, NOS due to its self-limiting course and good response to conservative therapy.