[Application of electron microscopy in the diagnosis of neoplasms]

The majority of neoplasms can be diagnosed by light microscopy, but in some cases the diagnosis remains ambiguous due to poor differentiation, even though special stainings have been employed. This paper presents 34 cases of neoplasms in which the tumors were diagnosed by electron microscopy. This includes distinguishing (1) anaplastic carcinoma from lymphoma; (2) anaplastic carcinoma from amelanotic melanoma; (3) APUDoma from other tumors; (4) different mesenchymal tumors. The diagnoses of 4 cases of malignant melanoma, 11 cases of APUDoma, 7 cases of poorly differentiated carcinoma or anaplastic carcinoma, 2 cases of non-Hodgkin's lymphoma, 9 cases of mesenchymal tumors and 1 cases of other tumors have been resolved by electron microscopy. It is obvious that in some cases, electron microscopy can be of help in establishing a correct diagnosis.