Primary cutaneous CD8(+) small- to medium-sized lymphoproliferative disorder in extrafacial sites: clinicopathologic features and concept on their classification.

Three cases with CD8+ small- to medium-sized lymphoproliferations in the skin at extrafacial sites are described. Clinically, the patients presented with papulonodular or plaque-like lesions without preceding patches. Histopathologically, nonepidermotropic nodular or diffuse infiltrates were composed of small- to medium-sized pleomorphic lymphocytes, which expressed CD8 (more than 80% of the cells) and granzyme B (60%-70% of the cells), but were negative for CD4, CD30, and CD56. There was no association with Epstein-Barr virus. A clonal T-cell population was detected in 2 patients. Staging examinations did not reveal extracutaneous involvement. The 2 patients with solitary lesions underwent complete remission after radiation therapy, whereas 1 patient developed multifocal lesions and several recurrences. These CD8+ small- to medium-sized lymphoproliferations of the skin at extrafacial sites may belong to a spectrum of phenotypically and prognostically heterogeneous cutaneous small- to medium-sized lymphoid proliferations, which are characterized by an indolent course in most patients.