Osteosarcoma of the wing in a sulfur-crested cockatoo.

A 26-year-old female sulfur-crested cockatoo (Cacatua galerita) was evaluated for vocalizing through the night and extending her right wing. Physical examination revealed a large, firm mass extending from the humerus to the distal aspect of the elbow. Computed tomography confirmed a large aggressive mass of the right distal humerus with a large soft tissue component, severe osteolysis, and adjacent periosteal proliferation. Fine-needle aspirates of the mass were most compatible with sarcoma, and osteosarcoma was prioritized. An unstained slide was treated with nitroblue tetrazolium chloride/5-bromo-4-chloro-3-indolyl phosphate toluidine salt-phosphatase (NBT/BCIP) substrate for ALP detection and was strongly positive, confirming a diagnosis of osteosarcoma. A month later, the patient underwent wing amputation and arrested during recovery from anesthesia. Post-mortem examination and histopathology were consistent with osteosarcoma. This case report highlights a rare occurrence of osteosarcoma in a cockatoo as well as its cytologic and histologic features. Additionally, this report provides support for NBT/BCIP application in ALP-expressing tumors, a cytochemical stain that has been minimally investigated in avian species.

Retrospective analysis of histologic lesions in captive arachnids.

Invertebrates, including arachnids, are a common taxon in zoological collections. Invertebrate medicine and pathology are emerging subspecialties, but there is limited reference material or published resources describing histologic lesions in arachnids. Histopathology of 26 captive arachnids (20 spiders and 6 scorpions) from institutional collections was reviewed. Most animals were found dead with limited clinical signs. Tissues evaluated included body wall (cuticle and epidermis), skeletal muscle, book lungs, digestive tract (pharynx, esophagus, sucking stomach, midgut tube, midgut diverticula, and stercoral pocket), central and peripheral nervous system, heart, hemolymph vessels and sinuses, Malpighian tubules, coxal glands, and gonads. Inflammation was frequent (24/26, 92%), and seen in multiple organs (18/24, 75%) with the midgut diverticulum most commonly affected (14/24, 58%) followed by the book lungs (13/24 arachnids, 54%), and body wall (8/24 arachnids, 33%). Inflammation comprised hemocyte accumulation, hemocytic coagula, melanization, and nodulation. Infectious agents, including bacteria (11/26, 42%), fungi (10/26, 38%), and parasites (2/26, 8%), were seen within inflammatory aggregates. Coinfection with multiple infectious agents was common (6/24, 25%). No etiologic agent was identified in 7/24 (29%) cases with inflammatory lesions. Lesions suggestive of decreased nutritional status or increased metabolic rate included midgut diverticula atrophy in 11/26 (42%) animals and skeletal muscle atrophy in 6/26 (23%) animals. Atrophic lesions were seen in combination with infection (8/11, 73%), pregnancy (2/11, 18%), male sex (2/11, 18%), or without other lesions (1/11, 9%). Other suspected contributors to death included dysecdysis-associated trauma (2/26, 8%) and uterine intussusception (1/26, 4%). No animals had neoplasia.