Could you miss these clues? Deceptive presentations of Metastatic Spinal Cord Compression

This month, I encountered a woman with metastatic breast cancer whose pain presented a challenge to her oncology team. The key to helping her, as is often the case, was to ask ourselves, “Where is the lesion causing the intractable pain?” 

The woman was admitted for bilateral hip pain and was receiving radiation to her hip metastases when she began to complain of increasingly intolerable left shoulder pain. The shoulder and arm looked perfectly normal on x-ray and CT, so we were asked to provide symptomatic relief for her. During our evaluation, however, she reported that the pain radiated from her left shoulder to her left hand, with numbness of the 4^th and 5^th fingers of that hand. We found that her strength was decreased as well, 3/5 grip, biceps, and triceps compared to her right arm and hand.

As I’m sure you know, none of this would have been explained solely by metastases to her shoulder. The dermatome affected was C8-T1, and the muscle weakness indicated the problem was not a new one. We considered three possibilities for injury to these nerves: (1) Her original tumor was in the left breast, and she’d received post-operative radiation after her mastectomy 3 years previously. Was this post-radiation fibrosis?  (2) Had the tumor recurred in her left supraclavicular lymph nodes and spread to her brachial plexus? Or (3) Did she have cervical spinal cord metastases with epidural extension into the C8-T1 nerve foramina?

Post-radiation fibrosis was unlikely. The nerves typically involved in post-radiation fibrosis are C-5 and 6 because the clavicle protects the lower brachial plexus nerves, C7-T1. But MRI of the brachial plexus gave us the answer. It showed a large lesion in the C7-T2 vertebrae extending to the extradural soft tissue and the C7-T1 and T1-T-2 foramina, explaining her pain and weakness. She had no tenderness to palpation of the cervical vertebrae—the shoulder pain radiating down to her hand and her weakness were the clues.  Her pain remitted immediately with the addition of dexamethasone, and she responded well to radiation of the mass with resumption of her left arm strength and sensation in her 4^th and 5^th fingers. 

Full disclosure: I did a sabbatical with Drs. Kathleen Foley at MSKCC in the early 90s and she taught me the importance of the neurological exam in patients with cancer. She was the first to describe the Cancer Pain Syndromes [1, 2], some of which I’ll be discussing in this newsletter.

The hallmark of the syndromes from direct lymphomatous extension or extension of vertebral tumor into the epidural space is that the patients present with pain “below” the lesion in their spine. Those with an atlas fracture or an odontoid lesion will have severe neck pain radiating over the posterior part of the skull to the vertex as well as neck stiffness, mimicking meningitis. If the tumor is not identified in time, these patients may develop paraplegia or quadriplegia from the subluxation and spinal cord or brainstem compression.

Patients with metastases to C7 don’t have neck pain. They present with pain between the scapulae. Plain films of the thoracic spine will miss these lesions, as will MRIs if the spine is imaged only at the site of pain in the thoracic region.

Patients with lesions at T6 with tumor or bone collapse that compresses the T6 root may present with pain that mimics that of a heart attack or an ulcer. These lesions are especially dangerous, because the spinal artery at T6 is the most vulnerable — the spinal canal is narrowest there.  If the patient develops enough epidural disease to compromise blood flow in that artery, the artery will become ischemic or infarct, and the patient will develop paraparesis or even paraplegia with loss of bowel and bladder function. When you’ve eliminated cardiac and GI pathology, consider a thoracic spine MRI.

Patients with metastases at T12 will present with pain in the hip and no tenderness to palpation of the spine or hip.  There’s still spinal cord at T12, so you need a high index of suspicion when the hip and pelvis films are normal. Again, you’ll need a spinal MRI.  Other than a myelogram, the MRI is the gold standard to investigate whether the patient has epidural disease that may progress to a metastatic spinal cord compression (MSCC) (3).  

The key in all these cases will be to remember that the patient will present with pain “below” the area of spinal metastasis, so the imaging needs to include spinal levels higher than the location of the pain. Opioids can be helpful, but dexamethasone is the standard of care for patients with MSCC. When I suspect epidural extension of tumor, well before they have sensory or neurologic findings, before I get the MRI, I start dexamethasone. I have had patients who couldn’t tolerate the MRI until we gave them the dexamethasone.

But there’s no good data on how much dexamethasone to give (3) We know very high doses (e.g. 20 mg) can cause delirium and other side effects, and that smaller doses (e.g. 4 mg) produce excellent pain relief, decrease inflammation, and so likely preserve the spinal artery. But we don’t know exactly how much or how often to give the dexamethasone.  For a patient with documented MSCC, my practice (when there are no contraindications) is to start dexamethasone at 4 mg po/IV q.i.d. and taper after the radiation.  For pain from epidural disease without MSCC, 4 mg po/IV at 8am and 2PM (to preserve sleep) is often sufficient.

I’ve included a Table (below) of the locations of these deceptive vertebral metastases leading to epidural tumor spread and eventual MSCC and the typical sites of referred pain. With a high index of suspicion, and an understanding of the clues, MSCC can often be prevented. If you are interested in a more extensive discussion of MSCC, including indications for surgery, please go to: https://janetabrahm.com/resources/pain-management-for-cancer-patients/#spinal-cord-compression

As always, please share this with any colleagues you think will find it of interest.

References

1. Foley KM. Cancer pain syndromes. J Pain Symptom Manage. 1987 Spring;2(2):S13-7. doi: 10.1016/s0885-3924(87)80035-0. PMID: 3647078.
2. Abrahm JL. Comprehensive Supportive and Palliative Care for Patients with Cancer. 4^th edition, 2022, Johns Hopkins University Press. pp.221-225
3. Lawton AJ, Lee KA, Cheville AL, Ferrone ML, Rades D, Balboni TA, Abrahm JL. Assessment and Management of Patients With Metastatic Spinal Cord Compression: A Multidisciplinary Review. J Clin Oncol. 2019 Jan 1;37(1):61-71. doi: 10.1200/JCO.2018.78.1211. Epub 2018 Nov 5. PMID: 30395488.