[Indolent lymphoma of the ear]

In 2007, Petrella et al. identified a new entity: CD8 T-cell indolent lymphoma of the ear.

A 40-year-old man presented a nodular erythematous and violaceous painless lesion on his right ear that had appeared four months earlier. Excision histology revealed a non-epidermotropic T-cell proliferation infiltrating the entire dermis and subcutis but with sparing of a grenz zone. The monotonous infiltrate was positive for CD8, CD3, CD5 and TIA-1, and negative for CD30, CD4, CD56, ALK and EMA. The Mib1 proliferation index was 20%. Lyme serology and PCR for EBV were negative. Additional examinations showed no extracutaneous involvement.

CD8+ indolent lymphoma is an entity first described in 2007 and reported in the literature in 15 patients. Lesions are located on the nose or external ear. It comprises a non-epidermotropic proliferation of CD8+ T lymphocytes negative for CD4, CD30, CD56, CD57, granzyme B and perforin. The Mib1 proliferation index is low. This new entity appears neither in the 2005 World Health Organization/European Organization for Research and Treatment of Cancer (WHO/EORTC) classification of cutaneous lymphomas nor in the WHO 2008 Classification of tumours of haematopoietic and lymphoid tissues. Surgical treatment or radiotherapy is sufficient, and unlike aggressive, epidermotropic CD8+ T lymphomas chemotherapy is not required.