[Myelomonocytic chloroleukemia. Histochemical evaluation of two observations]

A myelosarcoma was diagnosed in the bioptic excision of an eight year old boy's middle ear. An autopsy of this case as well as that of a 47 year old man revealed the presence of tumoriform chloroleukaemia. The histochemical positivity of naphthol AS-D-chloracetate-esterase and NaF-sensitive non-specific esterase showed the simultaneous double differentiation of tumour cells thus serving as evidence of their myelomonocytic nature. The first observation also revealed the presence of atypical eosinophil leucocytes with PAS-positive, naftol AS-D-chloracetate-esterase-negative granules. Both observations brought evidence of the reticular as well as tumour cells showing signs of erythrocytophagia which may have a share in the development of the tumour tissue green coloration.