Extranodal adult T-cell leukemia/lymphoma of the head and neck: a clinicopathological study of nine cases and a review of the literature.

Extranodal adult T-cell leukemia/lymphoma (ATLL) of the head and neck is a rare disease. We studied the clinicopathological features of nine patients with ATLL involving extranodal head and neck sites and conducted a literature review. Six patients presented with extranodal mass of the head and neck, whereas three had disseminated diseases. Tumors involved the parotid gland, sinonasal tract, masseter muscle, mandible and skull. Histopathology included diffuse pleomorphic-type (with angiocentric features), Hodgkin-like and anaplastic large cell-type. Five patients with localised disease showed prolonged survival regardless of unfavourable histology and/or aberrant provirus status, including integration of multiple copies or defective provirus. Patients with localised disease documented in the literature, including our study series, had a reduced frequency of elevated lactate dehydrogenase, no hypercalcemia and longer survival. ATLL should be included in the differential diagnosis of extranodal head and neck lymphoma. Localised extranodal ATLL of the head and neck may exhibit indolent clinical behaviours.