Histochemistry of B663 Pigmentation: Ceroid-Like Pigmentation

Since its use was first reported by 8rowne and Hogerzeil in 1962 ('0. /I), 8663, a synthesized phenazine dye, has proven to be an effective drug in the treatment of human leprosy and its use has become worldwide ( 2.7.9 " . 26. 3~. 39. 52. 5.1 ). The most significant and frequent side effect of this compound is an abnormal skin coloration. This can be divided into two types. One is an initial ruddiness that usually takes place within one to four weeks after the beginning of treatment ( 39 ) and is reported to be due to accumulation of the drug itself, mainly in the reticuloendothelial cells and fat ( 5.6. 16.45 ). It occurs in deposits as round bodies or in crystalline f orm ( 2. 6. 16. 45. 52.53 ) . The other pigmentation consists of a blackish-brown or violaceous-brown pigmentation that develops during the second and third months of treatment ( ~. 39. 53 ) and is limited mainly to lesion areas. Some investigators ( X.39 ) have reported histopathologic studies indicating that the pigmentation is caused by an increase of melanin in the basal layer of the epidermis, associated with incontinence of pigment into the upper dermis ( U9 ). Others, however, have been unable to detect significant changes in the amount of melanin in such skin. No reports have been found which attribute this pigmentation to pigments other than melanin. The present histochemical study presents evidence to the effect that part of the pigmentation is due to the deposition of a lipid pigment, a ceroid-like substance, in the cytoplasm of the macrophages (lepra cells) . This substance is generally believed to be derived from lipids and to be rendered insoluble to fat so lvents by oxidation ( 37 ).