Systemic B-cell lymphoma presenting as an isolated lesion on the ear.

We report a case of systemic B-cell lymphoma that presented as an isolated cutaneous lesion on the ear, mimicking a primary cutaneous B-cell lymphoma. Although there was no clinical evidence of systemic disease, bone marrow involvement was found on further investigation and subsequent immunoglobulin gene analysis revealed an identical clone in the skin lesion and bone marrow aspirate. Evidence of a t(14 : 18) translocation was not identified. This case is unusual for several reasons. First, involvement of the pinna as a presenting feature of systemic lymphoma has not been reported previously. Second, the cutaneous lesion had been present for 3 years prior to diagnosis and there has been no clinical progression of systemic lymphoma during 2 years of follow-up. Third, the lymphoma does not correspond exactly to any of the entities in the REAL classification of systemic B-cell lymphoma. This case underlines the indolent nature of some systemic B-cell lymphomas and the need to investigate thoroughly patients with disease apparently confined to the skin.