Vascular Malformations in the Thoracic Vertebrae of Three Cats

Abstract

Lytic bony lesions which histologically consist of proliferation of well-differentiated small endothelial-lined blood or lymph vessels separated by loose connective tissue have been described in humans. These lesions have been termed skeletal angiomatosis, hemangiomas, and vascular malformations. 1.2.e8 This report describes a similar disease in three young cats.Case 1 was a 20-month-old male domestic long-haired cat which presented at 17 months of age for posterior paresis that was responsive to antibiotics and steroids. It re-presented at 20 months for bilateral proprioceptive deficits. Hemogram was normal, and feline leukemia virus tests were negative. Myelogram indicated obstruction of contrast material at T2 with decreased bony density at T,. Owners elected euthanasia. At necropsy the referring veterinarian found a pinkish-tan 1.0 x 0.5 x 0.3 cm extradural mass protruding into the spinal canal. The spinal cord in the region was compressed.Case 2 was a 1-year-old castrated male domestic shorthaired cat which presented at 14 months and again at 15 months of age for pain and progressive posterior paresis and ataxia. Plain radiographs showed a lytic area at TI,, I; a myelogram was compatible with extramedullary compression of the spinal cord at TI I . A surgical dorsal decompression at TI, and T I , was done. The bones of the dorsal laminae and articular facets appeared to the surgeons to be "thickened but porotic" and were felt to be the cause ofthe cord compression. Portions of these bones were submitted for histopathologic examination. Three months post-operatively the cat was free of clinical disease.Case 3 was a 15-month-old female domestic long-haired cat which had a 1 -year history of posterior paresis which was progressively less responsive to steroid therapy. Plain radiographs revealed a moth-eaten appearance of bone at T, involving the dorsal vertebral body, pedicles, and laminae. Myelogram indicated an extradural compression at T,. Owners elected euthanasia. The formalin-fixed and decalcified specimen of T, revealed red-brown irregular masses within the dorsal and transverse spinous processes on cut section. A 0.6 x 0.4 x 0.6 cm red-brown mass protruded into the spinal canal and compressed the adjacent spinal cord (Fig. 1).Histologically, sections from all cases were similar. Vessels of varying sizes with endothelial cells, prominent pencytes, and variable amounts of smooth muscle were present within a loose connective tissue stroma separated by bony trabeculae (Fig. 2). Some of these vessels, interpreted to be arterial, contained red blood cells; others were empty. The bony trabeculae were predominantly lamellar with moderate numbers of osteoblasts and infrequent osteoclasts present. Hemopoietic elements were displaced by vascular proliferations and stroma. Vascular proliferations extended along marrow spaces and vascular channels to the periosteum in case 1, and focally infiltrated a nerve in case 3, where extensive remodeling of surrounding bone was also found. These bony and vascular proliferat...

Feline Spinal Cord Diseases

“…Intraosseus vascular malformations (IVM) causing spinal cord compression have been described in 3 young cats between the ages of 15 and 20 months with a history of 3 to 12 months of chronic progressive posterior paresis partially responsive to corticosteroid therapy. 81 In some cases, the presentation of IVM can be similar to a neoplastic disease; plain radiographs showed focal decreased bone density or lysis of thoracic vertebrae, T2, T4, and T10-11, respectively; and myelography showed obstruction of the contrast column or extradural compression in all cases. 81 The lesion was described as vessels of varying size with endothelial cells, prominent pericytes, and variable amount of smooth muscles among a loose connective stroma separated by lamellar bony trabeculae, with osteoblasts and infrequent osteoclasts.…”

“…81 In some cases, the presentation of IVM can be similar to a neoplastic disease; plain radiographs showed focal decreased bone density or lysis of thoracic vertebrae, T2, T4, and T10-11, respectively; and myelography showed obstruction of the contrast column or extradural compression in all cases. 81 The lesion was described as vessels of varying size with endothelial cells, prominent pericytes, and variable amount of smooth muscles among a loose connective stroma separated by lamellar bony trabeculae, with osteoblasts and infrequent osteoclasts. 81 The bony and vascular proliferations caused severe spinal cord compression.…”

“…81 The lesion was described as vessels of varying size with endothelial cells, prominent pericytes, and variable amount of smooth muscles among a loose connective stroma separated by lamellar bony trabeculae, with osteoblasts and infrequent osteoclasts. 81 The bony and vascular proliferations caused severe spinal cord compression. Despite the aggressiveness of vascular proliferations, Wells and Weisbrode 81 considered these lesions as developmental anomalies based on the young age of the cats and the well-differentiated appearance of the vessels including endothelial, perithelial, smooth muscle, and fibrous cells.…”

Imaging Diagnosis—imaging and Histopathologic Characteristics of a Vertebral Hamartoma in a Cat

“…Computed tomography demonstrated an expansile lesion compressing the spinal cord, which was surgically resected, also resulting in a good outcome. Important differential diagnoses for vascular hamartomas occurring within bone include hemangiomas, hemangioblastomas, and arteriovenous malformations, and these can be differentiated on the basis of histopathological features …”

“…Important differential diagnoses for vascular hamartomas occurring within bone include hemangiomas, hemangioblastomas, and arteriovenous malformations, and these can be differentiated on the basis of histopathological features. [14][15][16][17] Previous studies have described MR characteristics associated with intramedullary hamartomas in the cervical and thoracic spinal cord of dogs. 18,19 In contrast to our case of a vertebral hamartoma, these case reports describe the intramedullary hamartomas as heterogeneously hyperintense compared to normal spinal cord on T2W images, isointense on T1W images, with no evidence of contrast in cervical hamartoma and some peripheral, ventral contrast enhancement in the thoracic hamartoma.…”