Soft Tissue, Subcutaneous panniculitis-like T-cell lymphoma, CD7 stain

This is a rare form of primary cutaneous T-cell lymphoma, predominantly affecting the subcutaneous fatty tissue. It is a cytotoxic T-cell lymphoma that preferentially involves subcutaneous tissue and expresses TCR-αβ. The dense lymphoid infiltration primarily involves the subcutaneous adipose tissue. Close look at the malignant cells reveal obvious atypia, with pleomorphism and numerous mitotic figures.

Demonstration of TCR-αβ is important, considering the differential diagnosis of primary cutaneous γδ T-cell Lymphoma. Mature T-cell phenotype is observed, with aberrant loss of CD5, CD7, and CD2 (in decreasing order). The majority of cases will show CD8 positivity.

This lymphoma is a clinically indolent entity, but progression can be seen.

This slide shows CD7 stain. See Related Content for H&E, CD3, TCR beta, and CD8 stains.