Nuclear grooves have been described as a cytologic feature in a variet
y of extrathyroid lesions. When a cytologic specimen demonstrates pr-e
minent longitudinal nuclear grooving, a wide range of pathologic lesio
ns should be considered To our knowledge, the two cases presented are
the first report of longitudinal nuclear grooving described in cytolog
ic preparations of malignant melanoma. (C) 1998 Wiley-Liss, Inc.