Generalized melanosis secondary to malignant melanoma. Report of a case with serum and tissue tyrosinase studies
✍ Scribed by Norman Sohn; Stephen L. Gumport; Heinrich Gang; Menek Goldstein; Ludwig M. Deppisch
- Publisher
- John Wiley and Sons
- Year
- 1969
- Tongue
- English
- Weight
- 585 KB
- Volume
- 24
- Category
- Article
- ISSN
- 0008-543X
No coin nor oath required. For personal study only.
✦ Synopsis
A case of generalized melanosis secondary to malignant melanoma is described. The tyrosinase activity of serum and tissues from this patient has been measured. The first 2 steps of melanogenesis (tyrosine + dopa and dopa + dopachrome) have been separately assayed. Serum and homogenates from skin and spleen showed the highest activity in both steps. Weak activity was detected in vagina and lung, but no activity was detected in the adrenals, kidney, liver, and rectum. An endogenous compound which inhibits the enzymic activity as well as the auto-oxidation of dopa is found to be present in almost all of the tissues analyzed. Tyrosinase activity was not found in serum samples from control patients without malignant melanoma nor from other patients with malignant melanoma without generalized melanosis. Inhibition of tyrosinase activity by endogenous substances, however, was present in all serum samples analyzed.
ENERALIZED MELANOSIS OCCURS VERY RARELY
G as a complication of malignant melanoma. It was first described in 1884.8 A review of the literature revealed 11 cases with none reported since 1961.1, 39 4, 6, 8, 11, 12, 14, 18, 19, Many explanations have been offered for this rare and dramatic phenomenon, but its pathogenesis has not been conclusively elucidated. Recently, such a patient was admitted to our institution, offering an opportunity for extensive and unique clinical, anatomical, and biochemical studies.
T h e enzyme tyrosinase plays a prime role in melanogenesis, and it is therefore reasonable to assume that a pathologic overproduction of melanin, like that encountered in melanoma, could be associated with abnormal