Melanin inclusions in the peripheral blood leukocytes of a patient with malignant melanoma.

ABSTRACT

Dark pigmented inclusions were found in the monocytes and polymorphonuclear leukocytes of a patient with widely metastatic malignant melanoma. Special stains demonstrated the granules were composed of melanin. The authors are not aware of any previous case report of patients with metastatic malignant melanoma that had leukocytic melanin inclusions. Prospective search for this phenomenon in malignant melanoma patients may allow such a finding to be used as a diagnostic tool.