Primary Cutaneous Anaplastic Large Cell Lymphoma With TCR-γδ Expression: A Case Series of Eleven Patients of a Rare Immunophenotypic Variant.

Abstract

Background: Primary cutaneous anaplastic large cell lymphoma (pcALCL) and lymphomatoid papulosis (LyP) are indolent CD30-positive lymphoproliferative disorders that rarely express TCR-γδ. However, primary cutaneous gamma-delta T-cell lymphoma (pcGDTCL), characterized by TCR-γδ expression on neoplastic cells, is a rare, aggressive cutaneous T-cell lymphoma with a poor prognosis. Accurate differentiation is essential due to distinct clinical behavior and treatment.

Methods: We identified 11 TCR-γδ-positive pcALCL cases from internal and consultation files, verified by two cutaneous lymphoma experts, with clinicopathologic data recorded.

Results: The median age was 68 years (range 38-95). Most cases presented as a single dermal lesion on the upper extremities. All were ALK-negative, CD30-positive (> 90% tumor cells), TCR-βF1-negative, and diffusely TCR-γδ-positive. CD4-/CD8- (54.5%) and CD4+/CD8- (45.5%) immunophenotypes were observed. CD2 (63.6%) and CD3 (54.5%) were the most common T-cell antigens. Ulceration, inflammation (both 45.5%), and necrosis (36.4%) were frequent. Angiotropism, angiocentricity, and myxoid stroma appeared in one case; epidermotropism in two. Four of ten tested were DUSP22-rearranged, and TP63 was negative in all eight tested.

Conclusions: Most ALK-negative TCR-γδ-positive pcALCL were CD4-/CD8-, followed by CD4+/CD8-. DUSP22 rearrangement occurred in 40% of cases, similar to reports in typical pcALCL. Its prognosis and the role of DUSP22 are yet to be clarified.