Myospherulosis of the breast. Diagnosis by fine needle aspiration

A case of myospherulosis of the breast diagnosed by fine needle aspiration biopsy is reported. The characteristic spherules and "endobodies" stained red by the Papanicolaou stain and brown by the Wright stain. In this case, human fat may have been an endogenous inducing agent for the spherule formation from erythrocyte products.