[Electron microscopic study on the diagnosis of 223 neoplasms]

223 neoplasms were submitted to electron microscopic (EM) study and diagnosis during a three-year period. It was demonstrated that EM provided a more precise pathologic diagnosis in 135 cases (60%), corrected the original diagnosis by light microscopy (LM) in 11 cases (5%) and confirmed diagnosis made by LM in 62 cases (28%). Anyhow, EM failed to give a good turn to the diagnosis in 15 cases (7%), because of unsatisfactory specimen provided or improperly processed. EM contributes greatly to the diagnosis of neuroendocrine tumors and the neoplasms from skin and soft tissue. The study verified that EM is of significant diagnostic value, for its capability of more accurately defining the histogenesis of certain tumors.