Abstract
Six cases with malignant melanoma and a case with melanotic freckle Hutchinson, were studied by electronmicroscopically. In the cases with malignant melanoma, numerous long ellipsoid melanosomes and premelanosomes were noted in the 3 cases, while numerous oval, ring like and/or partially melanized melanosomes were observed in the other 2 cases with melanoma arising from melanotic freckle Hutchinson. Melanosomes and premelanosomes in another case, were distinctly small in size and decreased in number. In a case with melanotic freckle Hutchinson, melanosomes and premelanosomes were generally ellipsoid and/or round. A direct communication of endoplasmic reticulum to melanosome was noted in 2 cases.
