Cytology of myeloma cells.

A cytological, cytochemical, and cytometric study of plasma cells from 195 cases of multiple myeloma showed that, contrary to earlier reports, flaming cells, thesaurocytes, and intranuclear inclusions are not confined to IgA-secreting cases but are common also in IgG and Bence Jones varieties of myeloma. IgA-secreting cells are not larger, nor do they have a lower nuclear cytoplasmic ratio than other myeloma cells. On average, for a given mass of tumour, Bence-Jones, IgG, and IgA varieties of myeloma produce amounts of paraprotein in the ratio 1 to 1-6 to 2-7.