Abstract
Background: Breast cancer is currently the most diagnosed cancer globally. For patients who complete breast cancer treatment, developing a survivorship plan is important, including serial history, physical examinations, and annual mammograms to look for recurrence and metastasis. Case Report: This is a case report of a 76-year-old female with a history of recurrent breast cancer who presented with lower-back pain and found to have MRI findings initially concerning for intradural extramedullary metastatic disease. Biopsy was later found to be consistent with benign spinal schwannomas. Conclusion: We present a unique case of spinal masses in the setting of breast cancer initially concerning for leptomeningeal spread, later found to have benign schwannomas that mimicked leptomeningeal spread on imaging. To our knowledge, this is the first reported case of schwannomas mimicking leptomeningeal spread in a patient with a history of recurrent breast cancer. After metastasis is excluded, schwannomas should be considered in the differential of benign spinal lesions.
Breast cancer is currently the most diagnosed cancer globally. In 2020, 2.3 million women were diagnosed with breast cancer, and it accounted for 685,000 deaths (1). Estrogen receptor modulators such as tamoxifen have shown a measurable reduction in breast cancer incidence and aromatase inhibitors like anastrozole have been shown to decrease breast cancer risk by half (2). In a study that looked at the 20-year risk of breast cancer recurrence after stopping endocrine therapy at five years, the cumulative risk of distant recurrence at 20 years was 13%, and cumulative risk of death was 7% for T1 cancer with zero positive lymph nodes (3). For patients who complete breast cancer treatment, developing a survivorship plan is important. This surveillance includes serial history and physical examinations and annual mammograms to look for recurrence and metastasis (4).
Leptomeningeal carcinomatosis is a form of metastatic cancer that invades into the layers of the dura and subarachnoid space surrounding the central nervous system. It can present in a variety of ways including, but not limited to, headaches, seizures, altered sensorium, and radicular pain. Although it has a low incidence rate of 5% among breast cancer patients, it is associated with high morbidity and mortality (5). We discuss a case of recurrent breast cancer with abnormal mammogram findings during an annual cancer survivorship evaluation. Initial workup was concerning for leptomeningeal spread of breast cancer, but further workup showed benign schwannomas.
Case Report
A 76-year-old female with a history of breast cancer presented to a cancer survivorship clinic for her yearly breast surveillance exam. She had a history of left-sided T1sN0M0 intraductal breast carcinoma in 1998 that was treated with a lumpectomy with adjuvant radiation and subsequent right-sided T1CN0M0 infiltrating ductal carcinoma in 2001 that was treated with a right lumpectomy and adjuvant radiation. The tumor was determined to be ER/PR positive and HER-2/neu negative. She received tamoxifen from 2001 to 2003 and was then switched to anastrozole from February 19, 2003, to December 15, 2003. This was discontinued because of severe arthritis pain that resolved within a month of drug cessation. She was subsequently doing well and under surveillance with yearly survivorship clinic exams.
Past medical history was significant for migraines, gastroesophageal reflux disease, hypertension, hypothyroidism, right-eye glaucoma, basal cell carcinoma, all of which were stable from prior care and managed by her primary care provider. Past surgical history was significant for excision of basal cell carcinomas, tonsillectomy during her childhood, and the above-discussed breast surgeries. Social history was negative for smoking, alcohol, and intravenous drug use. Family history was significant for a mother with history of breast cancer, uterine cancer, and skin cancer of unknown type. Her father had history of melanoma.
She was seen at her yearly cancer survivorship clinic visit in 2019. Her only new symptom at that time was lower-back pain in the setting of a recently passed right-sided kidney stone. The remaining review of systems was negative. Pertinent physician exam findings included bilateral lumpectomy scars. Her right breast had an area of <0.5 cm slightly raised skin lesion. She had a 3D mammogram that showed a new irregular mass in the peri-areolar right breast. This was further characterized as a new hypoechoic mass in the right peri-areolar breast and noted as BI-RADS Category 4B on ultrasound. Because of this finding, she was sent for a breast biopsy and bone scan. Because of a new complaint of lower-back pain, she was sent for an MRI of the lumbar and sacral spine. Her breast core biopsy results were consistent with fat necrosis. A nuclear medicine bone scan showed degenerative changes of the skeletal system and focal uptake present within the right distal humerus. MRI findings showed a non-enhancing sclerotic lesion S2 sacral segment that was likely benign given stability from prior CT in 2014, a nonspecific osseous lesion in the L4 vertebral body that represented likely vertebral body hemangioma, and multiple numerous enhancing nodular intradural masses throughout the lower thoracic and lumbar intradural space (Figure 1). According to the radiologist, intradural metastasis cannot be excluded but favored to be neurogenic lesions.
T2 (A) and T1 (B) MRI sagittal imaging of the lumbar spine showing nodular enhancing intradural masses especially around the conus medullaris (arrows) and cauda equina (arrowheads).
Given the MRI findings, she also had further imaging workup with an MRI of the brain, cervical spine, and thoracic spine. MRI of the cervical and thoracic spine was concerning for intradural extramedullary metastatic disease (Figure 2). No spinal cord compression or abnormal spinal cord signal were seen. No prior MRI of the spine was done with which to compare these findings. The patient had prior CT scans of her chest, abdomen, pelvis, but these findings were not seen. The MRI of the brain revealed T1 enhancement over the anterior right parietal lobe with dural thickening, concerning for leptomeningeal spread of tumor over the right parietal lobe (Figure 3). No parenchymal metastasis was seen.
MRI of the cervical spine axial T1 showing rounded enhancing lesion left of the midline (arrow).
MRI of the brain findings concerning for leptomeningeal carcinomatosis A) MRI of the brain axial T1 enhancement in the right parietal lobe. B) MRI of the brain coronal T1 dural thickening noted along the right parietal lobe. Findings were initially concerning for leptomeningeal carcinomatosis.
Given these concerning MRI findings, the patient was sent to the neuro-oncology clinic for further workup. In the neuro-oncology clinic, she denied any symptoms, including headaches, balance problems, focal weakness, numbness, tingling, bowel or bladder incontinence, and seizures. Her neurological exam was significant for mild left-sided neglect when testing for peripheral vision and sensation. She had mild right-sided weakness in her arm and leg. She had some difficulty with delayed word recall but was a good historian overall. A lumbar puncture was ordered and cerebrospinal fluid studies including cytology were negative for malignancy. She was then referred to neurosurgery for biopsy of her spinal cord lesions to evaluate for metastasis.
In the neurosurgery clinic, she noted one recent episode of decreased vision that lasted two minutes and resolved on its own. She had repeat MRI and magnetic resonance angiography (MRA) of her brain, which were normal, with previously seen enhancement of the right parietal space no longer visible. It was determined she may have had a transient ischemic attack. She was then taken to the operating room and had a lumbar laminectomy, intradural exploration, and biopsy of cauda equina tumor using microdissection. Frozen-tissue analysis and final pathology results were consistent with schwannoma. She was offered testing for neurofibromatosis but declined. One year later she repeated MRIs of the brain and spine. MRI of the brain was negative for any acute findings. MRI of the spine showed stable schwannomas over the past year. Her only symptom is peripheral neuropathy, for which she is taking gabapentin.
Discussion
Spinal tumors are relatively rare, comprising 15% of central nervous system tumors. Most common spinal tumors are extradural and often metastatic lesions. Extramedullary, intradural spinal tumors (EISTs) are even more rare (6). Spinal metastases are common in malignancies and are most common to the vertebral column. Extramedullary, intradural metastases are very rare (1.5%-5% of spinal metastases), with few reports indicating that the most common primary is of lung origin (45%-54%), followed by breast (11%-26%) and renal (7, 8). Most EISTs are nerve sheath tumors (Schwannomas and neurofibromas), meningiomas, and filum terminale ependymomas from the most to least common, respectively (6). Schwannomas are the most common type of EIST. They can occur sporadically or in neurofibromatosis type 2, especially if there are multiple lesions.
Given these tumors are benign, patients are often asymptomatic, and these tumors are found incidentally. Schwannomas are typically found encasing dorsal sensory roots and most commonly in cervical and lumbar regions and are less frequently thoracic (6). EISTs can significantly compress and displace the spinal cord and nerve roots, causing myelopathy or radiculopathy as initial symptoms (9). Schwannomas have been classically described as hyperintense nodular masses within the dura with surrounding enhancement on MRI, similarly to our patient (7). Of note, leptomeningeal disease can also present as enhancing dural nodules especially of the cauda equina, similarly to our patient, highlighting the challenge in differentiating between metastatic disease and benign EISTs (5). In patients with symptomatic schwannomas, the gold-standard treatment is complete surgical resection. In patients who are not good surgical candidates, radiotherapy can be used (10).
A few case studies for axillary masses in patients with breast cancer showed them to have schwannomas after surgery. A 47-year-old patient with invasive breast carcinoma was found to have an axillary mass six months after partial mastectomy and axillary dissection. An excisional biopsy was done because of concern for axillary lymph node metastasis, but she was found to have an axillary schwannoma (11). In another case, a 68-year-old patient who did have local breast cancer recurrence also had an axillary lymphadenectomy during surgery and was incidentally found to have an axillary schwannoma (12). Other case reports have detected schwannomas in other locations among patients with breast cancer, including pleural tissue and the brachial plexus (13, 14). In patients like these and ours, it is difficult to determine whether lesions are benign or malignant based on MRI findings alone. Despite the rarity of EISTs secondary to metastasis, it has been reported and must be considered. Out of five reported cases of spinal metastasis to cauda equina, one was the initial presentation of recurrent breast cancer. In two cases, MRI findings of extramedullary, intradural metastasis appeared similarly to those of benign nerve sheath tumors (6, 7). In these cases, the lesions are more localized, not widespread with numerous lesions throughout the intradural space.
Conclusion
To our knowledge, this is the first reported case of schwannomas mimicking leptomeningeal spread found in a patient with a history of recurrent breast cancer. After excluding malignancy, it is important to consider benign tumors like schwannomas on the differential and offer further workup including genetic testing and to discuss treatment with symptomatic patients.
Acknowledgements
Editorial assistance was provided by Moffitt Cancer Center’s Office of Scientific Publishing by Daley White and Gerard Hebert; no compensation was given beyond their regular salaries.
Footnotes
Authors’ Contributions
Drs. Samuel Jalali, Kavita Renduchintala, and Thanh-Phuong Afiat participated in the writing and editing of the manuscript. Dr. Smitha Pabbathi participated in editing the manuscript.
Conflicts of Interest
The Authors have no conflicts of interest to declare in relation to this study.
- Received July 18, 2023.
- Revision received August 19, 2023.
- Accepted August 25, 2023.
- Copyright © 2023, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved
This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY-NC-ND) 4.0 international license (https://creativecommons.org/licenses/by-nc-nd/4.0).
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