Cytomorphologic and cytochemical aspects of malignant histiocytosis with spindle-cell differentiation. A case report.

Spindle-cell differentiation and tumor formation have been observed rarely in cases of malignant histiocytosis. We describe below one case of malignant histiocytosis with spindle-cell differentiation. Touch preparation of autopsy material revealed cytologic features that correlated with the histologic appearance of atypical components of this entity, such as spindle and nonspindle histiocytes and abundant erythrophagocytosis. Cytochemical properties indicated the histiocytic nature of the cells that composed this tumor. A morphologic account of the different types of cells is presented.