potassium-permanganate and Skin-Neoplasms

To establish a procedure that can effectively bleach melanin from pigmented lesions without affecting quantification of argyrophilic staining of nucleolar organizer regions (AgNORs).. Twenty banal compound nevi, five from each of nonpigmented, slightly pigmented, moderately pigmented and heavily pigmented groups, were bleached by 10% H202 for periods of 0 (nonbleached controls) and 24 hours. AgNOR size and count parameters of nevomelanocytic nuclei were measured by video image analysis. Melanin bleaching using KMnO4 was also investigated.. In all lesions treated with 10% H202 for 24 hours, the melanin was bleached effectively, with no qualitative change in AgNOR appearance. There were no significant differences in mean AgNOR number per nucleus (AgNOR number), mean individual AgNOR size (AgNOR size) or mean percentage of AgNOR area per nucleus (% nuclear area) between nonbleached and bleached sets in both the nonpigmented and slightly pigmented groups. However, disintegration of AgNOR dots was observed in those treated with 1% KMnO4 for 5, 10 and 15 minutes. There were significant decreases in AgNOR size (P = .002) and % nuclear area (P = .003) and increase in AgNOR number (P = .05) in the slightly pigmented group evaluated when treated with 1% KMnO4 for five minutes.. Melanin in pigmented lesions can be bleached effectively with an H202 procedure without significantly affecting AgNOR staining properties in contrast to bleaching with KMnO4.

Topics: Hydrogen Peroxide; Melanins; Nevus, Pigmented; Nucleolus Organizer Region; Potassium Permanganate; Silver Staining; Skin Neoplasms; Time Factors

Distinguishing heavily pigmented melanocytes from melanophages on routine hematoxylin and eosin slides can be difficult. Melanin bleaching with potassium permanganate solution is a traditional means of removing melanin from tissues and can be used before immunohistochemical staining to remove any pigment that might be confused with the brown chromogen diaminobenzidine. Azure B stains melanin granules green-blue, easily contrasts with diaminobenzidine, and may be used as a counterstain on unbleached sections after immunohistochemical staining. To our knowledge, studies comparing melanin bleaching with azure B counterstaining in the immunohistochemical evaluation of malignant melanomas have not been performed. Paraffin sections from 33 heavily pigmented malignant melanomas were bleached with a 3.0-g/L potassium permanganate solution, immunohistochemically stained for S-100 and HMB-45, and counterstained with hematoxylin. Unbleached sections were similarly stained for S-100 and HMB-45 and counterstained with azure B. To establish optimal permanganate concentrations, a variable number of sections were bleached with lower permanganate concentrations ranging from 0.125 to 2.5 g/L. S-100 antigenicity was preserved at all permanganate concentrations, whereas HMB-45 antigenicity was abolished at concentrations of 0.5 g/L and greater. At permanganate concentrations from 0.125 to 0.5 g/L, both antigenicities were preserved; however, melanin was incompletely removed. Complications of bleaching included tissue damage and loss of cytologic detail. Positive immunohistochemical staining was observed in azure B counterstained sections. Azure B stained melanin greenblue and was easily distinguished from the brown diaminobenzidine chromogen, regardless of the antibody tested. Neither tissue damage nor loss of cytologic detail was observed. We conclude that the use of azure B counterstaining is superior to permanganate bleaching in the histologic evaluation of heavily pigmented cutaneous malignant melanomas.

Topics: Antigens, Neoplasm; Azure Stains; Humans; Immunoenzyme Techniques; Melanins; Melanocytes; Melanoma; Melanoma-Specific Antigens; Melanophores; Neoplasm Proteins; Pigmentation; Potassium Permanganate; S100 Proteins; Skin Neoplasms; Staining and Labeling

The accumulation of excessive amounts of melanin in melanocytic lesions can obscure cellular morphology and can further hinder immunocytochemical procedures. We have used a modification of the potassium permanganate/oxalic acid melanin-bleaching technique, involving much reduced bleaching times, in order to remove melanin granules prior to incubation with primary antibody. We have assessed a panel of antibodies applicable to the evaluation of melanocytic lesions and in addition have also assessed antibodies that may be more useful in research. The study attempts to determine which antigens may be affected by bleaching and which are not. Antigens S100, HMB 45, NKIC3, CD34, and L26 are relatively unaffected by this procedure. Factor-VIII-related antigen and vimentin and CD68 antigens produced enhanced staining. In contrast, antigens CD3, CD31, and CD45RO were abolished. In addition, smooth muscle actin and desmin antigens demonstrated considerable nonspecific background staining and were not reliable in this study. This technique demonstrates that a fairly wide range of antigens are preserved after bleaching and that distinction between melanocytes and melanophages can reliably be performed using the conventional immunocytochemical chromogen 3,3-diaminobenzidine and without the need for elaborate counterstaining.

Topics: Actins; Antigens, CD; Antigens, CD20; Antigens, CD34; Antigens, Differentiation, Myelomonocytic; Antigens, Neoplasm; CD3 Complex; Desmin; Humans; Immunohistochemistry; Leukocyte Common Antigens; Melanins; Melanoma; Melanoma-Specific Antigens; Neoplasm Proteins; Oxalates; Oxidation-Reduction; Pigmentation; Platelet Endothelial Cell Adhesion Molecule-1; Potassium Permanganate; Reproducibility of Results; S100 Proteins; Sensitivity and Specificity; Skin; Skin Neoplasms; Vimentin; von Willebrand Factor

To investigate how nuclear morphometric variables, tumor thickness (measured according to Breslow), invasion depth (classified according to Clark), nuclear DNA content and type of DNA histogram are associated with each other in primary malignant melanomas of the skin.. Image analysis DNA cytometry and nuclear morphometry were performed on 85 primary skin melanomas. The relationships of size, sphericity and DNA content of melanoma cell nuclei; melanoma thickness; and Clark level were analyzed in detail. The effect of melanin bleaching on DNA cytometry results was studied.. Melanoma thickness correlated with nuclear size in aneuploid, but not diploid, melanomas. The prevalence of aneuploidy did not increase with tumor thickness. In aneuploid melanomas the proportion of cells with higher-than-diploid and higher-than-tetraploid DNA content increased with tumor size.. Aneuploidy is as common in thin as in thick melanomas. Genetic instability in aneuploid melanomas correlates with melanoma thickness. This correlation in aneuploid melanomas partially explains the correlation between nuclear size and melanoma thickness. In diploid melanomas no correlation was observed between nuclear size and melanoma thickness. DNA cytometry is a valuable tool for studies on the background of phenotypic changes in skin melanomas.

Topics: Adult; Aged; Aged, 80 and over; Aneuploidy; Cell Nucleus; Diploidy; DNA, Neoplasm; Female; Humans; Image Cytometry; Image Processing, Computer-Assisted; Male; Melanins; Melanoma; Middle Aged; Potassium Permanganate; Skin Neoplasms

Cutaneous plasmacytomas associated with local deposition of amyloid were diagnosed by light microscopy in a series of six older dogs (mean age 10.7 years) consisting of two Cocker Spaniels, a Poodle, a Weimeraner, and two mixed-breed dogs. The neoplasms occurred on the digits (2 dogs), forelimb (2 dogs), lip (1 dog), and ear (1 dog). In most cases, groups of neoplastic plasma cells were widely separated by large homogeneous islands of amyloid. The neoplastic cells had characteristic plasmacytoid features, but the degree of pleomorphism varied greatly between different neoplasms. In four of the six tumors, the diagnosis of plasmacytoma was confirmed by the demonstration of a monoclonal plasma cell population using immunofluorescent staining for anti-canine immunoglobulins. In these tumors, the neoplastic cells reacted with only one class of immunoglobulins (IgG). The amyloid did not react with any of the reagents used. The suspicion that the amyloid was of immunoglobulin origin (primary amyloid) was supported by its retention of birefringence under polarized light after treatment with potassium permanganate and staining with Congo red.

Topics: Amyloid; Animals; Congo Red; Dog Diseases; Dogs; Ear, External; Female; Fluorescent Antibody Technique; Follow-Up Studies; Forelimb; Humans; Immunoglobulins; Lip; Male; Microscopy, Electron; Microscopy, Fluorescence; Plasmacytoma; Potassium Permanganate; Skin Neoplasms; Staining and Labeling; Toes

With the increasing use of immunoperoxidase technics, it may be difficult to differentiate between the dark staining of 3,3'-diaminobenzidine (DAB) compound reaction product and melanin pigment. The latter may be particularly observed in skin. Samples of both normal skin and melanotic malignant melanoma were treated for the removal of melanin by standard technics both before and after a peroxidase-antiperoxidase (PAP) immunohistologic sequence. Many methods for the removal of melanin pigment resulted in diminished DAB staining intensity. Some also caused cellular disruption. However, the method of choice was found to be treatment with 0.25 g/dL potassium permanganate and 1 g/dL oxalic acid before the immunoperoxidase sequence.

Topics: 3,3'-Diaminobenzidine; Humans; Immunoenzyme Techniques; Melanins; Melanoma; Oxalates; Oxalic Acid; Potassium Permanganate; Skin Neoplasms