Ning Lin, MD1,5, Anita Huttner, MD, PhD7, Paul Spieler, MD4, Elizabeth B. Claus1,2,5, MD, PhD., Santosh Kesari, MD, PhD6
1. Departments of Neurosurgery, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts
2. Department of Epidemiology and Public Health, Yale University School of Medicine, New Haven, Connecticut
3. Department of Pathology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts
4. Commonwealth Oncology-Hematology, Haverhill, Massachusetts
5. Harvard Medical School, Boston, Massachusetts
6. Department of Neurosciences, Moores UCSD Cancer Center, University of California, San Diego, La Jolla, CA
7. Yale University School of Medicine, Department of Pathology, New Haven, Connecticut
CLINICAL HISTORY AND IMAGING
A 55-year-old female presented with low back pain radiating to her left leg. The pain started several years ago, and recently getting worse. The pain was intermittent, shooting quality that usually worsened after lying supine for a long time. She denied any bowel or bladder symptoms. Her past medical history and family history was unremarkable. Her physical exam was normal except for left lower extremity was 4+/5 for knee and ankle extension/flexion. She also had mild decreased light-touch sensation in the left L4 and L5 distribution with 2-beat clonus in her left leg. Her big toe was equivocal on the left and downgoing on the right.
Magnetic resonance imaging (MRI) of the spinal cord revealed multiple homogeneously enhancing, intradural, extramedullary lesions in the lumbar spine (Figure 1a, 1b) with the largest one located near the L5/S1 disc space (Figure 1c). MRI of the brain as well as cervical and thoracic spine did not reveal any additional lesions. Computed Tomography of the chest, abdomen, and pelvis did not reveal occult malignancy. As the etiology of these lesions was not clear, the patient underwent a L5/S1 laminectomy, intra-dural exploration, and biopsy of the largest lesion.
GROSS AND MICROSCOPIC PATHOLOGY
Intra-operatively, the lesion appeared creamy white in color and rubber-like in texture and was associated with several nerve roots. Frozen and permanent specimens were sent to pathology, with a preliminary reading of spindle cell tumor. Nerve-root stimulation and evoked potentials indicated the lesion was associated with nerves involved in motor and anal sphincter function. The patient recovered well from the surgery with stable neurological function.
Pathologic examination of the specimen revealed a lobular collection of bland spindled and epithelioid cells, with areas of dense hyalinization (Figures 2a, 2b). The tumor cells were strongly S100 positive (Figure 2c), and were negative for epithelial membrane antigen (Figure 2d). On high magnification, the lesion had foci with well-defined palisading tumor nuclei adjacent to an anuclear zone (Verocay bodies; Figure 2b).