Though it should be prohibitory to puncture the malignant melanoma, such an occasional chance to observe exfoliative cellular picure of the tumor was experienced as in a following case. N. T. 26 yrs. old female; Two years ago, she was admitted in the hospital for the tuberculous pleuritis of the right chest and the caries of the right rib. Medical treatment healed her of the trouble. When admitted, she complained of neuralgia of the chest and back and edema of the right sided body. Dullness on percussion and no breathing sound on auscultation were noticed in the right chest. Pleuritis of the right chest was suspected. Its cause, however, could not be clarified. Therefore, the pleural punction was performed for the diagnostic aim. In hemorrhagic pleural exudate many atypical cells, showing instructive cellular pictures, were noticed. And based upon the morphology of the above cells, malignant melanoma was firstly suspected. Six monthes later she expired for the wide disseminated malignant melanoma. This experience stimulated us to do further analysis of the cellular pictures of the exfoliated cells in three malignant melanoma cases (exfoliated cells in the sputum of a patient with pulmonary metastasis, and punctured cells in the subcutanous tumors of two late staged malignant melanoma patients). Based on the above four cases the following cytological characteristics of the malignant melanoma cells were found as follows; 1) Intranuclear vacuolation, occasionaly containing eosinophilics substance. 2) Fine granular, partially ncdular, chromatin aggregation. 3) Thin and smooth nuclear membrane. 4) Epitheloid arrangement with mutual inclusion. 5) Intracytoplasmic melanin granules. In addition the histological specimens of 21 malignant melanoma cases were analysed with special references to the above cytological characteristics. While the specimens were classified as three-histologi cal types, the above nuclear characteristics were evident in about 1/3 of stellate-cellular pattern (14 cases) and all of pleomorphic-cellular pattern (4 cases). In the remaining spindle-cellular pattern (3 cases) the nuclear characteristics was never noticed. Therefore, when the melanin granultes were taken in to consideration, it was suggested that the malignant melanoma was possiblly diagnosed by means of the exfoliative cytology in about 2/3 of all cases, differentiated from other malignant tumors.
A fluorescence microscopic study was made in application of supravital staining with acridin-orauge on the exfoliated cells of ten cases of normal oral mucosa, of 66 oral malignant neoplasms and of 26 cases of other oral lesions.