Incomplete Urethral Duplication Associated with a Dermoid Cyst within a Vascular Hamartoma in a Female Dog.

A seven-year-old spayed female Labrador retriever presented for necropsy following an acute history of thrombocytopenia, anemia, leukocytosis and abdominal effusion. A 2 × 3 × 10 cm, cylindrical to tubular, mottled red-to-tan mass extended from the caudal pelvic cavity caudally and ventrally under the dermis along the caudal aspect of the left pelvic limb adjacent to the semimembranosus and semitendinosus musculature. Histologic examination of the mass revealed a singular central lumen lined by urothelium that multifocally transitioned into non-keratinizing, stratified squamous epithelium associated with few hair follicles and sweat glands. The lumen was surrounded by a dense collagenous stroma containing numerous, variably sized blood vessels. The combination of lesions was consistent with a diagnosis of incomplete urethral duplication associated with a dermoid cyst and vascular hamartoma. To the authors' knowledge, this is the first report of an incomplete urethral duplication associated with a dermoid cyst within a vascular hamartoma.

Intracranial, extraneural ectopic lymph node in a bovine (Bos taurus).

The brain from a field necropsied 8-month-old feedlot heifer presenting with an acute history of depression, lethargy, dyspnoea and anorexia was evaluated grossly and by histopathology. The meninges overlying the left cerebral hemisphere contained a 12 × 26 × 32 mm, dark red, soft, ovoid mass. Histologic examination of this tissue revealed a well-organized lymph node with normal architecture. Organization of reactive lymphoid tissue resembling normal lymph node architecture may occur under chronic stimulation. However, there are no known aggregates of lymphoid tissue present within the cranial vault in any veterinary species. This is the first reported case of an intracranial ectopic lymph node in any species.

Syringomyelia in an Adult American Paint Horse.

Syringomyelia is a form of myelodysplasia defined by the formation of one or more fluid-filled cavities within the spinal cord that do not communicate with the central canal. The defect may be congenital or acquired. Clinical signs correlate to the segment of spinal cord affected and include pain, paresis, proprioceptive deficits, alterations in sensation, scoliosis, and autonomic dysfunction. This report describes the clinical and pathologic changes in a case of acquired syringomyelia in a 10-year-old American Paint Horse mare. The horse had a six-week history of progressive proprioceptive deficits in all four limbs, bilateral pelvic limb ataxia, and muscle fasciculations that were unresponsive to treatment with stall rest, phenylbutazone, and dexamethasone. Syringomyelia was diagnosed postmortem within cervical, thoracic, and lumbar spinal cord segments. Acquired syringomyelia should be considered among differential diagnoses in adult horses displaying progressive neurologic deficits.