Disseminated liposarcoma in a dog.

A 9-year-old, female Mongrel dog was presented for posterior hindlimb weakness, inability to stand, and pain in the lumbosacral and pelvic regions. Radiography revealed a lytic lesion extending from L5 to L6 to the ilium. At necropsy, an 8 x 2 to 3.2 x 3 cm, irregular, white, firm mass was identified extending from the left dorsolateral aspect of the L6 vertebrae to the sacrum, crossing the sacroiliac joint to the ilium, and reaching the acetabulum without affecting the joint cartilage. Tumor masses were also present bilaterally near the costochondral junction of several ribs. White, soft nodules were present in the heart, pericardium, lungs, spleen, and kidneys as well. Histologically, osteolysis with disruption of the cortical bone and reactive bone with the presence of multinucleated osteoclasts was noted. Neoplastic cells consisted of variable, small basophilic round cells (SBRC) with very scant cytoplasm, larger polygonal cells with abundant eosinophilic cytoplasm, and vacuolated cells resembling adipocytes. Within the marrow cavity, vacuolated cells with necrosis predominated, whereas in periosteal areas, polygonal and vacuolated cells that were mixed with a lower percentage of SBRC were more common. In the lungs and heart, SBRC predominated, and in the spleen, polygonal cells were more numerous. Tumor cells stained positive for vimentin and S-100 and stained negative for CD99, neuron-specific enolase, synaptophysin, chromogranin A, cytokeratins, desmin, myoglobin, and actin. This tumor most likely arose from the marrow cavity of the L6 and later invaded through the vertebral body into adjacent vertebrae and various visceral sites.     

Mesojejunoileac liposarcoma with intrahepatic metastasis in a dog

We report a liposarcoma at the mesojejunoileum that was widely excised, and then the intrahepatic metastatic liposarcoma was found. The dog was treated by two single-agent chemotherapy separately. The patient was an 8-year-old, male Dachshund, and was referred to our hospital owing to the significant distention of the left abdomen. Neither radiography nor ultrasonography detected the actual association of the tumor with the abdominal viscera before surgery. A large-sized tumor mass that adhered to the mesojejunoileum was explored by laparatomy. Final diagnosis of a pleomorphic liposarcoma was made by the routine histology and further identified by Oil Red O stain. The two single-agent chemotherapy including doxorubicin followed by capecitabine, however, failed to cause remission of the intrahepatic metastatic lesions. The patient died 22 months after operation and the cause of death was supposed to be metastatic liposarcoma.     

Extradural spinal synovial cysts in nine dogs

Nine dogs presenting for investigation of cervical or thoracolumbar myelopathies were diagnosed with extradural spinal synovial cysts. Degenerative disease affecting the articular facets or intervertebral discs was present on plain spinal radiographs in all cases. Myelography was consistent with dorsolateral, extradural spinal cord compression. Two groups of dogs were identified: (1) young, giant breed dogs with multiple cysts involving one or more levels of the cervical spinal cord; and (2) older, large breed dogs with solitary cysts involving the thoracolumbar spinal cord. The synovial cysts constituted the major compressive lesions in four of the dogs. Analysis of lumbar cerebrospinal fluid demonstrated albuminocytological dissociation, consistent with chronic compressive myelopathy, in six dogs. All dogs underwent decompressive surgery and the diagnosis of synovial cysts was confirmed histologically. The mean follow-up period was 17 months (range four to 36 months). At the time of follow-up, all dogs were fully ambulatory with improved neurological function compared with that at initial presentation.     

Epidural spinal myelolipoma in a dog

Epidural spinal myelolipoma was diagnosed in a 13-year-old, male Siberian husky that was referred for evaluation of progressive pelvic limb paresis and urinary incontinence. An epidural mass was detected by magnetic resonance imaging and computed tomography. The mass was removed and identified histopathologically as an epidural myelolipoma. Pelvic limb paresis improved after surgery, but urinary retention associated with neurological bladder dysfunction persisted.     

Cervical spinal cord astrocytoma in a dog

An astrocytoma of the cervical spinal cord was diagnosed in a 3-year-old Siberian Husky. The dog had an 8-week history of progressive neurologic deficits that finally resulted in nonambulatory tetraparesis. Neurologic examination, CSF analysis, myelography, exploratory laminectomy and histopathologic examination were performed. Intramedullary spinal cord tumors such as astrocytomas are rare, and this case illustrates the manner in which spinal cord tumors may be confused with other nervous system diseases, both from a clinical and clinicopathologic standpoint.     

Primary spinal cord lymphosarcoma in a dog

Primary lymphosarcoma of the spinal cord has been infrequently reported. This tumor was classified as intramedullary, the least common type of spinal cord tumor. The dog had rapid onset of paresis and paralysis, with no sign of spinal pain.     

Intradural spinal arachnoid cyst in a dog

An 8-month-old, spayed female dog was presented with signs localizing a neurologic lesion between the 3rd thoracic and 3rd lumbar vertebrae. An arachnoid cyst was diagnosed by myelography, and a dorsal laminectomy with durotomy was performed. The dog continues to do well 1-1/2 year after surgery.     

Cervical spinal arachnoid cyst in a dog

An 18-month-old, intact male Akita presented with a 12-month history of progressive ataxia, hypermetria, and loss of conscious proprioception of the thoracic and pelvic limbs. Neurological examination and myelography localized a lesion at cervical vertebrae 1 and 2 consistent with an arachnoid cyst. Hemilaminectomy and cyst fenestration led to virtually full recovery.     

Multicentric osseous lymphoma with spinal extradural involvement in a dog.

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.     

Cytologic, histologic, and immunohistochemical features of lingual liposarcoma in a dog

A 9-year-old female spayed mixed-breed dog was presented to the referring veterinarian with a history of decreased appetite and difficulty with prehension and swallowing because of a firm oval mass in the tongue. On cytologic evaluation of a fine-needle aspirate of the mass there were numerous round to polygonal cells organized individually or in loose clusters with rare branching capillaries. The cells had eosinophilic granular cytoplasm, round to oval nuclei, and occasionally indistinct borders. The cytologic diagnosis was granular cell tumor (GCT) of the tongue. Impression smears of a biopsy sample of the lingual mass contained similar eosinophilic granular cells with variable numbers of clear vacuoles in the background, numerous perivascular arrangements, and occasional lipoblasts, suggestive of liposarcoma. On histologic examination the tumor was composed of numerous lipocytes with rare foci of round eosinophilic granular cells without evidence of vacuolation; occasionally, atypical mitotic figures were seen. Immunohistochemically, the cells were uniformly negative for periodic acid-Schiff and did not express smooth muscle actin, desmin, or cytokeratin but were immunoreactive for vimentin and S100. A diagnosis of well-differentiated liposarcoma was made on the basis of morphologic and immunohistochemical results. Eosinophilic granular cells may be a component of well-differentiated liposarcoma and are not limited to GCT. Liposarcoma should be considered in the differential diagnoses of lingual tumors in the dog when cytological evaluation reveals eosinophilic granular cells consistent with GCT.     

Extradural spinal juxtafacet (synovial) cysts in three dogs

Three dogs were presented for investigation of spinal disease and were diagnosed with extradural spinal juxtafacet cysts of synovial origin. Two dogs that were presented with clinical signs consistent with pain in the lumbosacral region associated with bilateral hindlimb paresis were diagnosed using magnetic resonance imaging. Both cysts were solitary and associated with the L6-7 dorsal articulations; both the dogs had a transitional vertebra in the lumbosacral region. A third dog that was presented with progressive paraparesis localised to T3-L3 spinal cord segments and compression of the spinal cord at T13-L1 was diagnosed using myelography. A solitary multiloculated cyst was found at surgery. Decompressive surgery resulted in resolution of the clinical signs in all three dogs. Immunohistological findings indicated that one to two layers of vimentin-positive cells consistent with synovial origin lined the cysts.     

Malignant mediastinal extra-adrenal paraganglioma with spinal cord invasion in a dog.

A 1.5-year-old castrated, male, mixed-breed dog was evaluated because of a 2-week history of lethargy, stiffness, and progressive paraparesis. Spinal radiographs, myelography, and computed tomography of the region showed a locally invasive mass involving the thoracic wall. Upon necropsy, an encapsulated, fluctuant mass was noted attached to the right dorsal body wall in the region of the fifth to seventh thoracic vertebra. Churukian-Schenk staining revealed positive granules within the neoplastic cell cytoplasm and immunohistochemistry was positive for expression for cytoplasmic neuron-specific enolase and synaptophysin. Chromogranin A and S100 expression were found to be negative. Immunohistochemistry and silver staining did not allow further differentiation of the tumor, and the diagnosis remains consistent with either a chromaffin paraganglioma or a nonchromaffin paraganglioma (chemodectoma) with some production of catecholamines. Extra-adrenal paragangliomas are rare neoplasms in dogs but should be considered as a possible differential diagnosis for a primary paraspinal thoracic mass.     

Extradural spinal,bone marrow,and renal nephroblastoma

A 1-year-old, female intact Shetland sheepdog presented with acute onset of neurological signs. Physical examination revealed a large abdominal mass. Neurological examination revealed multifocal disease with neck pain, short-strided forelimbs, and hind-limb paresis with loss of tail and anal tone. Blood work, imaging techniques, cytopathology, and histopathology led to a diagnosis of renal, bone-marrow, and extradural spinal nephroblastoma. This report documents potential clinical and pathological manifestations of canine nephroblastoma that have not been previously reported.     

Proliferative potential of a spinal nephroblastoma in a young dog

The proliferative potential of a spinal nephroblastoma was studied in a young dog. A 4-month-old, female golden retriever showed developing deterioration in her gait and subsequent paralysis of her hind legs. At necropsy, a well-demarcated grayish brown tumor mass was found in the lumbar spinal cord segments between L2 and L3. Histologically, a blastemal cell tumor with a tubule- or glomeruli-like structure was found to be infiltrating intradurally. Proliferating cells at the S-phase, assessed using the bromodeoxyuridine (BrdU) labeling method, were seen occasionally in the tubular cells and glomeruli-like structures and were frequently seen in the blastemal cells. Immunohistochemically, the tubular epithelial cells were positive for cytokeratin, and the blastemal cells were positive for vimentin. The present tumor showed a high potential for growth and invasion, which suggests that it the potential to expand into the adjacent spinal cord.