Intramedullary Spinal Cord Metastasis in the Dog

Abstract

Intramedullary spinal cord metastasis (ISCM) was diagnosed in three dogs with signs of myelopathy. The clinicopathologic features of ISCM in these and previously reported cases in the veterinary and human literature were compared. Myelopathic signs associated with ISCM may be the initial clinical manifestation of malignancy or may develop in the patient with known malignancy. Pain, a frequent manifestation of extradural compressive myelopathy, is not a consistent feature of ISCM. Survey spinal radiographs are usually unrewarding and cerebrospinal fluid (CSF) abnormalities nonspecific. Myelog‐raphy is indicated to differentiate intramedullary lesions from more common extradural compressive lesions. Myelographic interpretation may be difficult, and intramedullary tumors must be differentiated from spinal cord edema or hemorrhage. Evidence of widely disseminated malignancy should increase suspicion for ISCM; hemangiosarcoma and lymphosarcoma should be considered the most likely histo‐logic types. CSF cytology may be helpful in the diagnosis of patients with lymphosarcoma. Prognosis is poor due to the frequent presence of disseminated disease, although temporary response to corticoste‐roid therapy may be achieved. More aggressive therapeutic approaches, such as spinal irradiation and microsurgical resection of metastases, have been advocated in humans but have not been reported in the dog. Although it is an uncommon complication of systemic malignancy, ISCM should be considered in the differential diagnosis of myelopathy in the dog. (Journal of Veterinary Internal Medicine 1990; 4:207–215)

Intramedullary Spinal Cord Neoplasia in 53 Dogs (1990–2010): Distribution, Clinicopathologic Characteristics, and Clinical Behavior

“…Only 5% of secondary tumors in humans are diagnosed antemortem, and affected patients present more acutely and progress more rapidly than patients with primary tumors . Clinical progression in previous veterinary reports ranged from 1 to 504 days (mean, 55.7 days; median, 21 days) . Our data also indicated a variable clinical course.…”

“…Fifty‐six intramedullary spinal cord tumors have been reported in the veterinary literature . Primary tumors were documented in 41 cases and secondary tumors in 15 cases . The mean age, recorded for 49/55 cases, was 4.7 years.…”

“…Intramedullary spinal cord tumors may not be readily amenable to surgery, although successful surgical removal has been described . Intramedullary spinal cord tumors have also been reported as being nonpainful and rapidly progressive . Historically, large breed dogs have been reported to be more susceptible to developing primary spinal neoplasms .…”

Neoplasia

“…They typically cause neurological deficits that progress rapidly. Tumors are either gliomas (12.4) or, very occasionally, metastatic tumors (Waters and Hayden, 1990;LeCouteur, 2001). Staging relies mainly on neuroimaging and MRI gives the best definition for intramedullary lesions.…”

“…Although it will remain an important imaging modality, myelography is invasive and image quality can vary due to technical problems such as contrast leakage or poor filling of the subarachnoid space (see Chapter 4). False-negative results can also occur, especially with nerve sheath tumors (Carmichael and Griffiths, 1981;Bradley et al, 1982;McCarthy et al, 1993) and myelography may miss as many as 42% of intramedullary tumors (4.41) (Grem et al, 1985;Waters and Hayden, 1990). Transverse imaging by CT or MRI in general allows earlier detection and better surgical planning than myelography (Waters and Hayden, 1990;Brehm et al, 1995).…”