Differential cytology of malignant melanoma

On the basis of 285 fine needle biopsies and smear preparations of malignant melanoma (both primaries and metastases), we present a catalogue of highly characteristic cytologic features: dissociation of melanoma cells, excessive dimension of the tumor cells, characteristic staining of the cytoplasm, structure of the nucleus, features of the nucleoli, aberrations of mitoses and amitoses. With the help of the cytologic catalogue, we are able to differentiate melanoma in a contrasting way from other diseases such as pigmented seborrheic keratosis, basal cell carcinoma, squamous cell carcinoma, and various lymphomas. Thus the differential cytology of malignant melanoma can be referred to for general criteria of malignancy on the one hand, as well as for the diagnosis of the specific tumor type and the epicrisis of uncertain histologic aspects on the other.