Pathogenesis of generalized melanosis with melanuria and melanoptysis secondary to malignant melanoma

Abstract

A case of disseminated malignant melanoma with generalized melanosis of the skin and other tissues, melanuria, melanoptysis, and a dark brown blood serum is reported. The reticuloendothelial system contained large amounts of melanin pigment. Lysis of degenerating pigment-loaded melanoma cells in peripheral blood vessels seemed to be of considerable importance in the pigmentation of tissues. Focal pigmentation of capillary endothelium and perivascular deposition of melanin pigment in macrophages and, occasionally contained large amounts of melanin pigment. Lysis of degenerating pigment-loaded melanoma cells in peripheral blood vessels seemed to be of considerable importance in the pigmentation of tissues. Focal pigmentation of capillary endothelium and perivascular deposition of melanin pigment in macrophages and, occasionally contained large amounts of melanin pigment. Lysis of degenerating pigment-loaded melanoma cells in peripheral blood vessels seemed to be of considerable importance in the pigmentation of tissues. Focal pigmentation of capillary endothelium and perivascular deposition of melanin pigment in macrophages and, occasionally, in other cells, was noted. Single cell metastases contributed to melanin pigmentation of most organs, but were not found in sections of the skin. Melanoptysis (black sputum) was due to diffuse melanoma cell infiltration of the lungs, with secondary pigment deposition in macrophages and in bronchial epithelial cells. In this case the 'glomerular melanoma cell emboli' recorded by previous authors consisted of melanin pigment and cell debris. Focal damage of glomeruli affected by pigment emboli is described allowing access of melanoma cell debris (including melanin pigment granules) into glomerular tubules.

Melanoptysis as a complication of fibreoptic bronchoscopy

“…The amount is then usually minor and not massive, as in the case presented here. Unusual causes of melanoptysis other than exposure to coal have been reported in the context of freebase cocaine smoking [10], malignant melanoma of the lung [11] and pulmonary aspergilloma caused by Aspergillus niger [9].…”

Malignant Melanocytic Schwannoma of the Nasopharynx

“…A number of theories have emerged to explain the presence of melanin pigment in neoplasms and ha martomas. One of the oldest views is that melanin is transferred from nearby nonneoplastic melanocytes to the tumor cells by 'cytocrine injection' as hypothesized by Masson [2], Another theory suggests that Schwann cells may actively phagocytize nearby melanin pigment [ 14,15]. Yet, another theory postulates the simultaneous proliferation of two distinct Schwann cells and melano cytes in a common neoplasm [16], Finally, and most likely, convincing ultrastructural and experimental evi dence has emerged to suggest that melanin synthesis may be accomplished by the neoplastic cells themselves [6,13,17,18].…”

Nævus bleu malin

“…Bien que peu fréquente, l'apparition d'une mélanose diffuse est classique en fin d'évolution des mélanomes malins [22][23][24][25][26][27]. Elle n'a néanmoins jamais été décrite au cours du développement d'un naevus bleu malin et notre observation est à notre connaissance la première décrite dans la lit térature.…”