History: A 3 year-old M/C Beagle is presented for a surgery consultation because of unusual neurological signs. The owner describes difficulty lifting the tail, and sometimes pain moving/wagging it. There may be difficulty defecating and sometimes urinating. Occasionally, the dog will chew or bite the right hind leg. He sometimes has muscle spasms, the owner is convinced, “because he is painful.” Signs have been getting worse despite treatments with prednisone and tramadol byu the referring veterinarian.
Physical and neuro exams: Physical exam within normal limits.
Neuro exam: normal hind leg reflexes with no proprioception deficits. The only abnormal finding is pain on palpation of the lower spine.
First impressions: Beagles are prone to intervertebral disc disease, but Joshua does not have the typical age or the classic signs for that. The history is definitely unusual, but we take the owner seriously and decide to investigate further. We suspect a neurological problem in the lower spine.
Work up: Pre-anesthetic blood work is within normal limits. An MRI of the lumbar spine is recommended. It shows a mass dorsal to the spinal cord, intradurally and extramedullary, between L5 and L6 (pictures 1 and 2 ).
First image which would be called a lateral on x-ray is called a sagittal
Second image which would be a DV on X-ray is called a coronal
Surgery: A dorsal laminectomy is performed between L5 and L6.
It reveals an approximately 2 cm long mass, dorsal to the cord (picture 3).
A durotomy is performed with a number 12 scalpel blade, and the mass is visualized (picture 4). Complete excision is deemed impossible.
A few incisional biopsy samples are taken… carefully (picture 5). This also allows debulking of the mass, which is reduced by about 2 thirds.
A few hours postoperatively, Joshua starts walking! And proprioception is normal !
Postop care 1: Joshua goes back home 2 days after surgery with instruction to strictly confine him. Five minute leash walks are allowed several times each day for eliminations. Cephalexin and tramadol are prescribed.
Histopathology: The mass turned out to be a chondrosarcoma, ie a cancerous tumor of the cartilage. Since it was intradural, and not in contact with the vertebrae, the pathologist believed it was “de novo” tumor formation.
Postop care 2: This is a slow-growing tumor, which ironically does not make Joshua a great candidate for chemo or radiation therapy since these modalities affect quickly-dividing cells.
Skin staples are removed after 2 weeks, and Joshua is doing great. There are no more signs of pain, even when he wags his tail.
He suddenly becomes occasionally fecally and urinary incontinent. Dexamethasone and a fiber-rich diet are recommended, and signs quickly decreased.
Eleven months postop, the owner noticed occasional pain. Amantadine was added to Joshua’s pain regimen (50 mg once daily).
Comments: This case report illustrates the fact that it is important not to dismiss a client’s description of unusual signs. Investigating the symptoms, advanced imaging of the spinal cord and surgery led to a happy conclusion. Joshua had excellent quality of life for several months postop. |
