Unusual case of cutaneous T-cell lymphoma with a prominent reactive population of B lymphocytes

A 58-year-old Japanese woman presented an eruption in the region of the back and the upper extremities, a subcutaneous nodule on the right breast, and a left cervical lymphadenopathy. The excision biopsy specimens, of a subcutaneous nodule and a lymph node, showed a vaguely nodular growth pattern comprising a small CD20 IgD lymphocyte infiltrate around clusters of medium-sized or large CD3 lymphoid cells,in which histological distinction between malignant lymphoma and reactive lymphoid hyperplasia was difficult. Southern-blot analysis revealed the presence of rearranged bands for the beta chain of the T-cell receptor,but not for the immunoglobulin heavy chain. The neoplastic cells were therefore identified to be of T-cell origin. This case represents an unusual cutaneous T-cell lymphoma with a prominent reactive population of B lymphocytes.