Clinicopathological features of CD56+nasal-type T/natural killer cell lymphomas with lobular panniculitis

Nasal-type T/natural killer cell lymphoma (TNKCL) shows frequent extranodal involvement including the skin, and is associated with a poor prognosis. W e hare studied six patients with nasal-type TNKCL presenting with inflammat ory subcutaneous nodular lesions with a subcutaneous lymphoid infiltrate. C linical information was obtained from the medical records of the patients a nd at follow-up.,All cases showed features of angiocentric lymphoma on hist ology, although there was diffuse cellular infiltration rather than an angi ocentric pattern in the subcutis. All six patients were similar in immunoph enotype: positive for CD56 and either cytoplasmic CD3 or CD45RO, but negati ve for B-cell, markers and CD30. bl situ hybridization using an anti-sense Epstein-Barr virus early regions probe showed a positive reaction in all ca ses, all patients either died with progressive disease or showed no respons e to combined chemotherapy. The diagnosis of nasal-type TNKCL, which has a fatal outcome, is facilitated by detection of CD56-positive tumour cells. I n evaluating lobular panniculitis including apparently benign inflammatory subcutaneous nodules, nasal-type TNKCL should be considered in the differen tial diagnosis, especially in Asian countries.