Benign cranial mediastinal lesions in three cats.

Cranial mediastinal lesions were detected in three cats, associated with respiratory impairment (case one), spontaneous pneumothorax (case two) and myasthenia gravis (case three), respectively. On gross and histological examination, the first case was considered either a lymphangioma or a branchial cystic mass of the thymic region of the mediastinum; a cystic lesion was suggested by sonographic detection of multiple anechoic cavitations within a circumscribed mass, while fine needle aspiration cytology excluded lymphosarcoma. The second case was diagnosed histologically as a cystic thymoma, but the third case was not examined microscopically.

Amoebic meningoencephalitis caused by Balamuthia mandrillaris in an orang utan.

Objective: To describe a case of meningoencephalitis caused by Balamuthia mandrillaris in an orang utan.

Design: A pathological case report.

Animal: A 20 years old male orang utan (Pongo pygmaeus).

Thymic lymphosarcoma of T cell lineage in a koala (Phascolarctos cinereus).

Objective: To diagnose and characterise thymic lymphosarcoma in a koala.

Design: A pathological case.

Animal: Seven-year-old female koala.

Proctitis associated with chlamydial infection in a koala.

Objective: To describe proctitis associated with chlamydial infection in a koala.

Design: A pathological study.

Animal: A free living, male koala aged 17 years.

Histological and immunohistological study of the developing and involuting superficial cervical thymus in the koala (Phascolarctos cinereus).

The thymuses of 44 koalas, ranging from less than 30 d to more than 14 y of age, were examined histologically and immunohistologically. The thymuses from 17 of these koalas dying acutely through trauma were regarded as not being significantly affected by disease and formed the basis for study of the normal thymus. Most other koalas had chronic illness and, consequently, disease affected (involuted) thymuses.

A longitudinal study of lymphocyte subsets in a cohort of cats naturally-infected with feline immunodeficiency virus.

Despite the potential of feline immunodeficiency virus (FIV) as an animal model for human immunodeficiency virus (HIV) studies, the long term effects of naturally-occurring infection have not been determined. HIV infection causes an ongoing deterioration in immune function which directly correlates with disease, in particular acquired immunodeficiency syndrome (AIDS). However, it is not known whether FIV-induced immunosuppression is progressive or related to the clinical condition.

Papillary ductal adenocarcinoma in the mammary glands of two horses.

Mammary gland neoplasms in horses are uncommon and may initially be confused with mastitis. Masses from the mammary glands of two horses with chronic discharges were examined by cytology and histopathology. Both masses were diagnosed as papillary ductal adenocarcinomas with extensive intraductal and intralobular involvement and only focal infiltration of the adjacent stroma.

Histological and immunohistological investigation of alimentary tract lymphoid tissue in the koala (Phascolarctos cinereus), brushtail possum (Trichosurus vulpecula) and ringtail possum (Pseudocheirus peregrinus).

The histological appearance and distribution of T cells, B cells and plasma cells were investigated for oropharyngeal tonsils, small intestinal lymphoid aggregations (Peyer's patches), caecocolic lymphoid patches and mesenteric lymph nodes of koalas (Phascolarctos cinereus), common brushtail possums (Trichosurus vulpecula) and common ringtail possums (Pseudocheirus peregrinus). The histological organisation and distribution of lymphoid cell subpopulations of these tissues were similar to those described in eutherian mammals, although some differences were found in comparison with previous descriptions of American opossum tissues. The main variation among the 3 species was in the structural organisations of the oropharyngeal tonsil and the caecocolic lymphoid patch which were more complex in the koala than in possums.

The distribution of organised lymphoid tissue in the alimentary tracts of koalas (Phascolarctos cinereus) and possums (Trichosurus vulpecula and Pseudocheirus peregrinus).

The anatomical arrangement of organised lymphoid tissues of the alimentary tract for 3 Australian marsupials, the koala (Phascolarctos cinereus), the common brushtail possum (Trichosurus vulpecula and the common ringtail possum (Pseudocheirus peregrinus), was determined by gross dissection and acetic acid treatment. Oropharyngeal tonsils were consistently found in the dorsolateral wall of the caudal oropharynx in all 3 species and additionally in the ventral soft palate of the koala. Aggregated lymphoid nodules (Peyer's patches) were present in the small intestine of koalas, ringtail possums and brushtail possums and were of similar appearance for all 3 species.

Malignant mast cell neoplasia with local metastasis in a horse.

A 12-year-old Arab stallion was presented with a chronically swollen right carpus resulting in profound lameness of the same leg. An incisional biopsy of subcutaneous tissue from the right carpus submitted for cytology and histopathology revealed large numbers of eosinophils interspersed by substantial numbers of variably sized and granulated mast cells. Fungal culture of a subcutaneous tissue sample taken from the right carpus was negative.