Angioimmunoblastic T-cell lymphoma with cutaneous involvement: a case report with subtle histologic changes and clonal T-cell proliferation.

Angioimmunoblastic T-cell lymphoma is a nodal peripheral T-cell lymphoma that rarely involves the skin. We describe a 62-year-old Taiwanese man who developed a second relapse of angioimmunoblastic T-cell lymphoma with generalized erythroderma and numerous plaquelike and nodular lesions. Biopsy of the erythematous skin lesion demonstrated mild infiltrate of atypical small lymphocytes, some with clear cytoplasm. The lymphoid infiltrate was located mainly around skin appendages and in the upper dermis without epidermotropism. Immunohistochemically, these atypical lymphocytes expressed CD3. Polymerase chain reaction analysis for T-cell receptor gamma-chain gene rearrangement using paraffin section showed the same-sized monoclonal bands in the skin and 2 previous nodal biopsies. We conclude that the histologic features of angioimmunoblastic T-cell lymphoma involving skin may be very subtle, showing only mild lymphoid infiltrate. Awareness of the history of angioimmunoblastic T-cell lymphoma with ancillary studies, including clonality testing for T-cell receptor gene rearrangement, is crucial for reaching an accurate diagnosis.