Primary cutaneous gamma delta T-cell lymphoma with brain involvement and hemophagocytic syndrome.

: Primary cutaneous gamma delta T-cell lymphoma is a rare diagnosis with only 40 reported cases. We describe a case of cutaneous gamma delta T-cell lymphoma with hemophagocytic syndrome and brain involvement that was not apparent morphologically on skin biopsy and was diagnosed as perifolliculitis and lobular panniculitis. The biopsy was sent later for molecular studies to the University of Washington, which demonstrated a T-cell clone. This case demonstrates that a T-cell clone may be present in a skin biopsy without morphologic or immunophenotypic evidence of lymphoma.