The significance of epidermal involvement in primary cutaneous gamma/delta T-cell lymphoma: a systematic review and meta-analysis.

Goyal, Amrita; O'Leary, Daniel; Duncan, Lyn M

BACKGROUND Primary cutaneous gamma/delta T-cell lymphoma (PCGDTCL) is a rare, aggressive peripheral T-cell lymphoma. There is evidence that patients with epidermotropic PCGDTCL may have an improved prognosis compared with those with only dermal and/or subcutaneous involvement. METHODS Systematic review of the literature and application of inclusion criteria yielded 48 manuscripts detailing the cases of 104 patients. RESULTS Individuals included 57 male (51.4%) and 47 female (48.5%) patients. Of 104 patients included in this analysis, 57 (54.8%) had no epidermotopism, 47 (45.2%) demonstrated any degree of epidermotropism, and 25 cases were predominantly epidermotropic (25/104, 24%). There was no significant difference in survival between these groups (P = 0.398). The most commonly performed immunohistochemical markers were CD3, CD4, CD8, CD5, CD7, CD30, CD56, TCR beta, TCR gamma, and TCR delta. There was no statistically significant difference in immunophenotype between groups. Lesion morphology was described in the majority of cases (85/104, 80.9%), most commonly some combination of nodules, plaques, and tumors (77.4%). Several cases had more atypical presentations, including "mycosis-fungoides-like" and ulcerated. Five-year overall survivals for patients with no epidermotropism, any epidermotropism, and predominantly epidermotropic presentation were 32.8%, 28.9%, and 40.0%, respectively (P = 0.40). CONCLUSIONS 1) Neither epidermotropism nor a predominantly epidermotropic phenotype in PCGDTCL predict a better prognosis and that 2) the case report literature in dermatology and dermatopathology is rich and highly valuable. This article is protected by copyright. All rights reserved.