Primary cutaneous gamma-delta T-cell lymphoma: Two cases and a review of the literature

Background: Primary cutaneous gamma delta T cell lymphoma (PCGD TCL) is a rare and rapidly progressive cutaneous malignancy that can be diagnostically challenging. Purpose: To improve characterization of the clinical and histologic features of PCGD-TCL. Methods: We present two patients with PCGD TCL and review an additional 97 PCGD TCL cases from the English literature. Results: A 51 year old male with biopsy proven psoriasis and a previously healthy 31 year old male with vitiligo developed PCGD-TCL. Initial biopsy specimens in both patients suggested tumor stage mycosis fungoides (MF), but subsequent histopathology confirmed PCGD TCL. Ninety-seven patients were identified in the literature, mostly males (53%) with a mean age of 55.2 years. Lesions most commonly involved the lower (60%) and upper (30%) extremities and existed a mean of 26 months before diagnosis. The most common immunohistochemical markers were EBV(-), CD3(+), CD4(-), CD5(-), CD7(-), CD8(-), CD30(-), CD56(+), granzyme-B(+), perforin(+), and βF1(-). Radiation and CHOP chemotherapy were the most common interventions and 52% of patients died. Conclusion: PCGD TCL is a devastating disease that can clinically and histologically mimic more common dermatologic conditions, such as psoriasis and MF, and its diagnosis may require multiple biopsies and review by a multi specialty pathology team.