title: Malignant chromatophoroma in a canebrake rattlesnake (Crotalus horridus atricaudatus).
abstract: An adult female canebrake rattlesnake (Crotalus horridus atricaudatus) at Zoo Atlanta (Atlanta, Georgia, USA) had a subcutaneous mass on the left lateral abdomen. Microscopically, the tumor contained a pleomorphic population of cells with abundant intracytoplasmic brown to gold nonrefractile pigment (chromatophores), large stellate cells resembling neurons, and small stellate cells whose cytoplasmic processes formed a fibrillar matrix. The pigment stained black with the Fontana-Masson technique and was positive with the periodic acid-Schiff technique (prior to and after diastase treatment). Neuron-specific enolase was detected in the large stellate cells using an immunohistochemical staining technique. In addition, glial fibrillary acidic and S-100 proteins were detected in the chromatophores with immunohistochemical staining. The smaller stellate cells were strongly S-100 positive. Ultrastructurally, chromatophores contained intracytoplasmic structures composed of concentric lamellar membranes bordered by a triple-layer outer membrane. The morphology of these structures was compatible with pterinosomes. Three fluorescent pigments were isolated from the neoplasm by one-dimensional chromatography and characterized by spectrophotometry and spectrofluorometry.
authors.affiliation: Department of Pathology, College of Veterinary Medicine, University of Georgia, Athens 30602, USA.
authors.forename: C R
authors.initials: CR
authors.lastname: Gregory
authors.forename: B G
authors.initials: BG
authors.lastname: Harmon
authors.forename: K S
authors.initials: KS
authors.lastname: Latimer
authors.forename: S
authors.initials: S
authors.lastname: Hafner
authors.forename: R P
authors.initials: RP
authors.lastname: Campagnoli
authors.forename: R M
authors.initials: RM
authors.lastname: McManamon
authors.forename: W L
authors.initials: WL
authors.lastname: Steffens
mesh_terms: D000818:Animals; D002854:Chromatography, Paper / Q000662:veterinary; D002856:Chromatophores / Q000648:ultrastructure; D017839:Crotalus; D005260:Female; D006651:Histocytochemistry; D007150:Immunohistochemistry; D008545:Melanoma / Q000737:chemistry / Q000473:pathology / Q000648:ultrastructure / Q000662:veterinary*; D008854:Microscopy, Electron / Q000662:veterinary; D011621:Pteridines / Q000032:analysis; D012878:Skin Neoplasms / Q000737:chemistry / Q000473:pathology / Q000648:ultrastructure / Q000662:veterinary*; D013050:Spectrometry, Fluorescence / Q000662:veterinary; D013053:Spectrophotometry / Q000662:veterinary
chemical_list: D011621:Pteridines