Melanocyte localization and distribution in human cholesteatoma.
Melanocytes in skin are derived from the neural crest and colonize the epidermis in the first trimester of gestation. Melanocytes have been observed in the nasopharyngeal, inner ear and oral mucosa and should therefore be present in the middle ear mucosa.



To identify and determine the distribution of melanocytes in human cholesteatoma and normal meatal skin in Caucasian adults.



Human cholesteatoma (n=18) and normal meatal skin samples (n=10) were investigated immunohistochemically with anti-HMB-45 and MART-1 antibodies. Localization and distribution of melanocytes were assessed in the epidermis and cholesteatoma using an automatic analyzing system.



Regular skin exhibited melanocytes within the epidermis and accounted for 10% of the total cell number. They occurred partly as membrane-bound clusters. Cholesteatoma matrix melanocytes were observed in the basal layer and exhibited an oval or roundmorphology. Decreased numbers of melanocytes in the basal layer correlated with keratinization within cholesteatoma samples. Melanocytes revealed monomorphous nuclei, abundant cytoplasm containing particles of melanin. Found adjacent to glands and blood vessels, melanocytes were also scattered among the mesenchymal cells. Accounting for 2-6% of the total cell number within the squamous epithelium, melanocyte density was significantly lower in cholesteatoma tissue than in skin.



The melanocyte distribution pattern was different when comparing the epithelia of skin and cholesteatoma. The presence of melanocytes in cholesteatoma may be due to an ingrowth, consequently controlled by keratinocyte-derived signals. In terms of the pathogenesis of cholesteatoma, neither squamous metaplasia nor melanocyte metaplasia can be excluded by our data.
Olszewska
Ewa
E
Department of Otorhinolaryngology Head and Neck Surgery, University of Bochum, Bochum, Germany. ewaolsz@yahoo.com
Wagner
Mathias
M
Goon
Peter
P
Shamaa
Ali
A
Upile
Tao
T
Rogowski
Marek
M
Steinstaesser
Lars
L
Sudhoff
Holger H
HH
D000911:Antibodies, Monoclonal / Q000276:immunology / Q000378:metabolism; D015703:Antigens, CD / Q000378:metabolism; D015214:Antigens, Differentiation, Myelomonocytic / Q000378:metabolism; D000951:Antigens, Neoplasm / Q000378:metabolism; D001706:Biopsy; D018424:Cholesteatoma, Middle Ear / Q000378:metabolism / Q000473:pathology*; D006644:Histiocytes / Q000378:metabolism / Q000473:pathology; D006801:Humans; D058965:MART-1 Antigen; D008264:Macrophages / Q000378:metabolism / Q000473:pathology; D008544:Melanocytes / Q000378:metabolism / Q000473:pathology*; D058950:Melanoma-Specific Antigens; D009092:Mucous Membrane / Q000378:metabolism / Q000473:pathology; D009363:Neoplasm Proteins / Q000276:immunology / Q000378:metabolism; D012867:Skin / Q000378:metabolism / Q000473:pathology*; D000097382:CD68 Molecule
D000911:Antibodies, Monoclonal; D015703:Antigens, CD; D015214:Antigens, Differentiation, Myelomonocytic; D000951:Antigens, Neoplasm; D058965:MART-1 Antigen; D058950:Melanoma-Specific Antigens; D009363:Neoplasm Proteins; C067980:CD68 antigen, human; D000097382:CD68 Molecule; C548667:MLANA protein, human