Occurrence of plasmocytoid cells in long-term blood-cell cultures from a patient with 'hairy cell' leukemia.

Cells from the peripheral blood of a patient with 'hairy cell' leukemia were cultivated in long-term cultures. They grew with a monolayer growth pattern and consisted of at least two cell populations. The electron microscopic morphology of the cultivated cells revealed cells resembling 'hairy cells' showing the typical cytoplasmic protrusions and cells with structural characteristics of plasma cells.