Tumor cell characterization in mycosis fungoides.

Five patients with tumor stage mycosis fungoides had tumor lesions excised and examined by light and electron microscopy. The tumor cells were also isolated and the percentages of E rosettes (T cells) and EAC rosettes (B cells) were determined and the rosettes examined by electron microscopy. The predominant cell type isolated from four of the five tumors was a T cell. Peripheral lymphocyte function measured by LTT to phytohemagglutinin and pokeweed mitogen was normal. Serum immunoglobulins gave variable results. The results support the concept that mycosis fungoides is primarily a T cell tumor involving the skin and morphologically similar to the Sézary cell.