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An 8-year-old stallion was evaluated because of recurrent urinary tract infections and chronic intermittent urospermia. After extensive diagnostic testing, it was hypothesized that the stallion had a reflex dyssynergia of the bladder and urethral sphincter. Initial attempts to manage the urospermia included semen fractionation, semen collection after voluntary urination, and use of semen extenders. None of these efforts reliably yielded a quality ejaculate. Administration of imipramine hydrochloride (1.2 mg/kg of body weight, PO, 4 hours prior to semen collection) was initiated in an attempt to enhance bladder neck closure during ejaculation. This treatment, combined with voluntary urination prior to ejaculation, resulted in ejaculates containing little or no urine. Using this protocol, 19 of 20 mares bred during the subsequent 2 years became pregnant. By the third year, the bladder dysfunction had progressed, and the urospermia was no longer manageable. Bladder catheterization, followed by manual expression of the bladder per rectum, were necessary prior to each semen collection to obtain a urine-free ejaculate. Three-and-a-half years after initial examination, transitional cell carcinoma of the bladder with metastasis was identified, and the stallion was euthanatized. It is not known whether the transitional cell carcinoma was related to the dysfunctional bladder. Imipramine hydrochloride did not eliminate, but did reduce, the frequency and degree of urospermia in the affected stallion for approximately 2 years.

The medical records of nine dogs with primary osteosarcoma distal to the antebrachiocarpal or tarsocrural joint were reviewed. Eight of the nine dogs were treated with surgical removal of the primary tumor; seven received adjuvant chemotherapy; and one dog was treated with chemotherapy alone. Median survival of dogs in this series was 466 days. Six of the nine dogs died of causes attributable to osteosarcoma, and both skeletal and pulmonary metastases occurred. Survival of dogs with osteosarcoma distal to the antebrachiocarpal or tarsocrural joint was somewhat longer than survival of dogs with osteosarcoma of more common appendicular sites. However, these are aggressive tumors with a high potential for metastasis.

A haemangiosarcoma in a horse resulted in ataxia affecting all four legs, a low head carriage and a reluctance to flex the neck. Ancillary diagnostic procedures included the analysis of cerebrospinal fluid, standing lateral cervical radiographs and a myelogram. Post mortem a tumour was found which involved the body of the second cervical vertebra and the associated hypaxial muscles, with secondary intravertebral extradural infiltration and focal compressive myelopathy. A histological examination showed that the tumour was a haemangiosarcoma.

Chordoma occurred in the sacrococcygeal region of the vertebral column of a 97-week old male control F344 rat. Macroscopically, it was a mass (20 mm in diameter) protruding into the retroperitoneum and the cut surface was white to dark-reddish and showed a gelatinous appearance. Histologically, the tumor was composed of physaliphorous and stellate cells growing in nests or cords and divided into lobules by a thin fibrous stroma. The tumor cells locally invaded adjacent tissues, but no metastasis to other organs was noted. Centrally, the tumor often had islands of bone that entrapped physaliphorous cells and the bone tissue consisted of well-differentiated osteocytes. Based on these findings, this tumor was diagnosed as chordoma with osseous element.

The course of naturally acquired infection with feline immunodeficiency virus was monitored in a cat over an 18-month period after diagnosis. The cat was admitted with diarrhea, poor body condition, a bite wound abscess, gingivitis, chronic fever, and splenomegaly. The cat's condition improved after splenectomy and remained stable for approximately 15 months, then began to deteriorate, as gingivitis, polyuria, polydipsia, pyrexia, multiple cutaneous masses, and hind limb paresis developed. The in vitro response of the cat's lymphocytes to mitogens was suppressed, and absolute lymphocyte counts were low. Spinal lymphosarcoma, disseminated mastocytoma, and presumptive diabetes mellitus were diagnosed after euthanasia. Decreased immune surveillance associated with feline immunodeficiency virus-related immunosuppression possibly played a role in the development of neoplastic disease in this cat.

A lakeland terrier puppy had progressive hindlimb ataxia associated with pain in the thoracic spine. Plain radiographs revealed a lesion affecting the dorsal neural arch of the fourth thoracic vertebra and myelography revealed compression of the spinal cord associated with the lesion. Surgical excision of the mass cured the dog's clinical signs. A histopathological examination of the excised tissue supported a diagnosis of osteochondromatosis.

A 9 month old Simmental fattening bull was presented with signs of a cauda equina syndrome. An epidurographic examination was made after thorough clinical, neurological and routine radiographic examination. The cause of the cauda equina compression--a spindle cell sarcoma--was revealed by the pathologic-histologic examination. This tumor caused the compression of the cauda equina and pathologic transverse fracture of the body of the first sacral vertebra and cranial epiphyseal fracture of the 1st and the 3rd sacral vertebra as well as the separation of the arcus from the first and second sacral vertebral bodies. Some other diseases which can cause cauda equina syndrome are mentioned.

Extra-adrenal paragangliomas associated with vertebral pain and clinical neurological abnormalities as a result of metastasis to the vertebral column were diagnosed in four dogs of different breeds by light microscopy. All were males (two intact and two neutered) aged 8 years. Metastatic neoplasms occurred as extradural masses with associated bone lysis at vertebrae C4 (2 cases), T12-L1 (1 case) and L4 (1 case). The neoplastic cells exhibited similar morphology with little variation between cases. All neoplasms showed cytoplasmic granules after staining with the Churukian-Schenk modification of the Pascual argyrophil stain for neurosecretory granules or for membrane bound electron-dense granules (dense-core granules). On immunohistochemical examination the neoplastic cells gave positive results for neuron-specific enolase and negative results for chromogranin and epithelial membrane antigen. Multiple organ metastasis and metastasis to bone have been reported previously, but these cases were unusual due to the involvement of the spine as an apparent predilection site for metastasis, and the sex (male) and age of the animals affected.

Although the treatment of central nervous system neoplasms generally is unrewarding, some animals with spinal neoplasia may, for a variety of reasons, be successfully managed for extended periods of time. The veterinary profession has greater experience with spinal surgery than with intracranial surgery. As a result, surgeons are more willing to attempt and more successful at removing or debulking spinal neoplasms. Additionally, there are more affordable and accessible diagnostic procedures available to evaluate the spinal cord than there are to evaluate the brain. Finally, the majority of tumors that affect the spinal cord are extramedullary and are therefore amenable to attempts to remove them surgically.

A multiple myeloma in an unusually young Cairn terrier (13 months, female) is described. Radiographically, pelvic tumor masses and characteristic systemic osteolysis were found at the end of the 4 week disease course. Therapeutic attempts were hopeless at this stage of the disease, but a form of chemotherapy is recommended.

Medical records of 21 cats with spinal lymphoma were reviewed. All cats were evaluated for neurologic deficits, although 85% of cats necropsied had multicentric disease. Eighty-one percent of cats had hind limb paresis. Results of FeLV tests were positive in 84.2% (16/19) of the cats, and 68.7% (11/16) of the cats had leukemic bone marrow. Spinal lymphoma was confirmed by necropsy in 13 cats, by examination of a biopsy specimen in 1 cat, and by examination of cells aspirated from an epidural lesion in 2 cats. In the remaining 5 cats, a presumptive diagnosis was made on the basis of neurologic examination findings, positive FeLV test results, and leukemic bone marrow. Nine cats were treated with chemotherapy alone. The complete remission rate was 50% in 6 cats given cyclophosphamide, vincristine, and prednisone. The median duration of complete remission was 14 weeks. Complete remissions were not observed in 3 cats given only corticosteroids. A single cat treated by laminectomy and postoperative chemotherapy had a prolonged remission (62 weeks). At necropsy, lymphoma of the CNS was limited to the vertebral canal in 10 of 13 cats; 2 cats had malignant tissue in the brain and vertebral canal, and in the remaining cat, the tumor extended into the brachial plexus. Most tumors extended over multiple vertebral bodies, and 4 cats had more than 1 level of spinal cord involvement. The lymphoma was high-grade lymphoblastic or immunoblastic type in all cats.

Multicentric osseous lymphoma involving the ribs and multiple vertebrae was observed in a 7-year-old Siberian Husky. Extradural spinal cord compression was treated by surgical decompressive hemilaminectomy of L1-2 without noticeable improvement of signs neurologic dysfunction. However, palliation of signs of pain was noticed after irradiation in conjunction with chemotherapy and surgical decompression.

Osteosarcoma was diagnosed in a 7-month-old female German Shepherd Dog with hind limb paresis. Radiography revealed a circumscribed calcified mass in the dorsal vertebral lamina at T13-L1 resulting in extradural compression of the spinal cord. Surgical excision of the mass resulted in gradual return to normal neurologic function. Four weeks after surgery, the dog became severely atactic after rolling onto its back. A chip fracture of T13 was identified, and the dog was euthanatized at the owners' request.

A metastatic thyroid solid-follicular carcinoma in the cervical portion of the spine was responsible for severe tetraparesis in a dog. Myelography revealed an extradural compressive lesion dorsal and to the right of the midline of C3. Histologic examination was used to diagnose the mass as a solid-follicular thyroid carcinoma. The primary tumor was not evident on cervical palpation or radiography. A dorsal laminectomy centered over C3 was performed, and all visible tumor was removed from the spine. The owner declined any further treatment for the dog.

Lymphosarcoma of the cauda equina in a domestic shorthair cat invaded the body of L7 and cranial portion of the sacrum. Clinical signs consisted of acute ambulatory paraparesis, tail paralysis, and dyschezia. Radiographically, there was evidence of bone lysis. Surgical exploration yielded a diagnosis, but did not induce improvement in the cat, which was subsequently euthanatized. Neurologic signs were similar to those associated with sacral nerve root avulsion injuries in cats.

An epidural neoplasm was removed from the right side of the third cervical vertebra of a Blue Tick Hound dog. By light microscopy the tumor was classified as a syncytial meningioma containing psammoma bodies that were histochemically positive for calcium salts, but negative for reticulum fibers and collagen. Ultrastructurally, the tumor cells had numerous processes and desmosomes. Cytoplasmic fibrils were sparse. Coated cytoplasmic vesicles frequently were fused with plasma membranes. The psammoma bodies were not within the cytoplasm, but were in spaces continous with the extracellular space. The bodies were composed of a medium electron-dense matrix; a crystalline, highly electron-dense center; and, sometimes, short fibrils embedded in the glanular matrix.

Three middle-age dogs had carcinosarcomatous tumors involving the lumbosacral bones and the soft tissues. A single metastatic lesion was found in each dog. The site of origin of this tumor was obscure.

An aged gray stallion was examined because of fullminating posterior paresis, bladder paralysis, and perineal anesthesia. Lower motor neuron dysfunction was detected at the lumbosacral level of the spinal cord, and cerebrospinal fluid was yellow. After brief supportive treatment, the horse died. Necropsy revealed a single epidural melanoma at L5-6. The absence of cutaneous melanotic growth, absence of organ involvement, and extensive vertebral remodeling indicated the neoplasm to have been primary and to have been present for an extended period. Neurologic dysfunction was acute and progressive, as a result of spinal cord compression by the neoplasm.

The pathological features of 29 spinal tumours are described. The most common tumours were those originating extradurally and included 10 vertebral neoplasms and 2 lymphosarcomas. Ten of the 29 were peripheral nerve tumours invading the spinal cord. The remaining 7 comprised 3 meningiomas, 2 ependymomas, one metastatic mammary adenocarcinoma and one haemangiosarcoma. There was a notable absence of glial tumours.

A thoracic vertebral (T5) osteochondroma was discovered in a 1 1/2-year-old male blue Persian cat with a history of acute hind limb paresis. Myelography revealed a mass on the dorsal surface of the vertebral body, which resulted in dorsal compression of the spinal cord. A dorsal laminectomy was performed, and the mass was rongeured entirely from the vertebral body. Although the cat's progress was initially slow after surgery, its neurologic status was assessed to be near normal, 15 months later.

Diseases of the back of horse and man are not comparable owing to the great difference in anatomy and posture. Veterinary surgeons, particularly in the United Kingdom, are often requested to account for a poor performance due to suspected "back trouble" but a complete examination of the horse's back is most difficult and care must be taken first to exclude any limb or foot lesions. Diseases of the bones, nerves and muscles are briefly discussed. Diagnosis must be improved by new radiographic and biochemical tests before the significance of back lesions can be assessed or even treated.

After a short introduction of theoretical principles of tomography, the advantages of this technique--especially the representation of the dog's spinal column--are discussed with five case histories. This technique allows to produce isolated pictures of special parts of the spinal column which may be superpositioned by other body parts like: atlantooccipitalregion (especially dens axis), caudal cervical spine, thoracical spine and lumbosacral region. Particularly the evaluation of the intervertebral spaces, the small vertebral joints and the contours and structures of the vertebrae is enhanced, which is important in tumorous and infectious processes, as well as in fractures and luxations of the vertebrae. Besides the spatial association of certain structures is possible if their localization with conventional x-ray methods and even with exposures in two planes is unsuccessful.