Spontaneous isolated lipoma of the choroid plexus in the baboon

Intracranial meningioma in a baboon (Papio spp.)

Meningioma is the most common intracranial non-glial tumour of cats, dogs and man. Few spontaneously arising brain tumours have been reported in non-human primates. This report describes a meningioma in a captive baboon. Clinical signs exhibited by the animal included head pressing, visual impairment and vestibular disease. The tumour arose from the ventral aspect of the cranial cavity and compressed the overlying left side of the cerebellum and brainstem. Microscopically, the mass was characterized by pleomorphic spindle-shaped to polygonal cells arranged in sheaths, vague whorls and occasional papillary structures on vascular cores. Nuclear cytoplasmic invagination, syncytial-like cells and areas of mineralization were also evident. Immunohistochemically, the neoplastic cells expressed vimentin and S-100 protein, but not pancytokeratin, glial fibrillary acidic protein or epithelial membrane antigen. The features of this tumour are similar to those of meningiomas in other species.

Lipoma of the urinary bladder in a cat

A 7-year-old male Persian cat was referred for necropsy examination a with history of progressive abdominal distention, dysuria, polyuria, colic and death. At necropsy examination, a raised white unencapsulated mass (3×6×4cm) was found on the mucosal surface of the bladder. The mass was lobulated with soft consistency similar to that of adipose tissue. Microscopical examination revealed cells identical to those of normal adipose tissue. On the basis of the gross and microscopical findings, the lesion was diagnosed as a lipoma. This tumour has not been recorded previously in the urinary bladder of a cat.

A review of spontaneous neoplasia in baboons (Papio spp.)

The baboon has become an increasingly important animal model and accurate information on baboon neoplasia is frequently required for biomedical research. To satisfy this demand, a complete literature search was carried out. Two hundred and four spontaneous neoplasms were found in published literature: 53 cases were male (26%), 76 were female (37%); sex was not reported in 75 cases (37%). Ages ranged from 3 months to 31 years (mean 14.1 years) in the 93 cases that reported them. Spontaneous neoplasms have been documented in Papio cynocephalus and Papio hamadryas as well as in most subspecies and hybrid combinations. The organ systems affected in descending order of number of neoplasms were hematopoietic (n = 53, 26%), alimentary (n = 52, 25%), urogenital (n = 35, 17%), integumentary (n = 26, 13%), endocrine (n = 14, 7%), nervous (n = 12, 5%), musculoskeletal (n = 4, 2%) and respiratory (n = 3, 1%). There were five miscellaneous neoplasms (2%) that could not be classified by system. Lymphosarcoma was the most common neoplasm (n = 51, 25%), and adenocarcinomas were second (n = 23, 11%), followed by squamous cell carcinomas (n = 10, 5%). Malignant cases numbered 114 (56%); 87 cases were (43%) benign. The malignancy of three cases (1%) was unreported.