[Fine structure of megakaryocytes in aleukemic megakaryocytic meyelosis]

Megakaryocytes from a case of aleukemic megakaryocytic myelosis were examined by electron microscope. They were considerably increased in number and their ultrastructure was different from normal megakaryocytes in certain aspects. Myelinfigures became demonstrable in the cytoplasm in increased number. An effective development of the demarcation membran system could not be observed.