Case Report
In July 2020, a 49-year-old woman was referred to our orthopedic spine clinic by an orthopedist colleague with diagnosis of lumbar disc herniation causing cauda equina syndrome. She had low back pain from six months ago, which was aggravated since the last week and was severe enough to completely disable the patient from her job and daily life. She described it as radicular to both lower extremities. It was aggravated by a short walk, 10 steps, and relieved only partially by lying decubitus and rest for at least 30 minutes. She described nocturnal pain since the beginning, but had no fever, malaise, and history of recent trauma, drug, or alcohol abuse. She mentioned no perianal/perineal anesthesia but some paresthesia of dorsal aspect of both feet.
On past medico-surgical history, she had invasive ductal carcinoma of right breast (ER-, PR-, HER2-) and had undergone right lumpectomy (2009). In 2017, she developed the same pathology in her left breast and was treated by left lumpectomy. She underwent standard chemoradiotherapy regimen after both surgeries and had no sign of recurrence in her regular follow-up.
On examination, there was no sign of skin rash or palpable mass in lumbar area. She had difficulty in walking. Mild tenderness was found over the lower lumbar vertebrae. Straight leg raise (SLR) and Cross SLR tests were positive bilaterally. The lower extremity muscle forces were 4/5 proximally and 3/5 distally. The dorsiflexion force of both ankles was 2/5. No sensory deficit was elicited. Patellar and Achilles deep tendon reflexes were decreased in both sides. There was no Babinski sign.
The magnetic resonance imaging (MRI) was in favor of a severe L4-L5 disc herniation with a large teardrop shaped sequestrum, which migrated caudally and caused severe canal stenosis at L5-S1 level. Sagittal and axial cuts showed compression of both L5 roots by the sequestrated disc in the L5-S1 neural foramina (Figure 1). However, due to the history of breast cancer and some MRI features, discussed in the ‘discussion’ section, we were suspicious of the diagnosis of DS. Her past follow-up positron emission/ computed tomography (PET/CT) in November 2019 showed increased FDG uptake in L5 and lower L3 endplate, which was interpreted as degenerative changes with no sign of metastatic lesions. Her last whole body bone scan (May 2020) also had shown only degenerative changes in L5.
Considering the eminent CES, we scheduled the patient for urgent decompressive laminectomy and discectomy. We performed the surgery through posterior midline incision by bilateral partial laminectomy and foraminotomy. However, after laminectomy, we found suspicious lobular tissue at the level of L4-L5 intervertebral disc bulging posteriorly into the spinal canal. As the patient had known history of breast cancer, we considered the tissue as metastasis, and tried to decompress the spinal canal and foramina by carefully removing the intra-canal mass, first diagnosed as a disc sequestrum on MRI by radiologist. Mass resection was performed with as minimal dissection as possible to avoid probable local tumor contamination. The whole resected tissue was sent for pathologic study (Figure 2). The intervertebral disc was completely intact, and we did not perform any discectomy. After sufficient decompression of canal and nerve roots, standard hemostasis and wound closure was performed.
The patient started ambulation the evening after surgery according to our postoperative protocol. Lumbar pain was significantly relieved. She was discharged after two days.
The pathology report was positive for metastatic breast -invasive ductal- carcinoma (Figure 3). We referred the patient to radio-oncologist, and she underwent a course of radiotherapy. Now, we have a seven-month follow-up of her, and she has had no recurrence so far.