Case 637 -- Neuromyelitis optica of the spinal cord clinically mimicking a neoplasm

Contributed by Craig Horbinski, MD, PhD1, Ian F. Pollack, MD2, Clayton Wiley, MD, PhD1, and Geoff Murdoch, MD, PhD1
Departments of 1Pathology and 2Pediatric Neurosurgery, University of Pittsburgh, Pittsburgh, PA 15213
Affiliations: CH was supported by a Callie Rohr American Brain Tumor Association Fellowship


CLINICAL HISTORY

The patient was a 10-year-old African-American female with a 1 year history of intermittent pain when she turned her neck, as well as pain in her shoulder and back. She also had a persistent rightward head tilt and progressive right hand weakness with paresthesias, as well as difficulty with ambulation secondary to progressive leg weakness. A full physical and neurological examination was significant for profound right hand weakness and sensory impairment, and bilateral lower extremity weakness and proprioceptive impairment.

Magnetic resonance imaging showed widening of the cervical spine with hypointensity on T1 (Fig. 1), increased intradural intramedullary T2 signal (Fig. 2), and contrast enhancement (Fig. 3). The abnormal T2 signal extended from the craniocervical junction to T5, and the abnormal enhancement extended from the craniocervical junction to T3. No abnormalities were seen in the remainder of the brain.

Corticosteroid therapy with dexamethasone was instituted, although the patient showed no improvement in either her symptoms or clinical findings. The spinal cord was thus decompressed via a C1 laminectomy and C2 through T3 osteoplastic laminotomy was then performed. The dura was tense from the underlying mass, which upon exposure was found to be brownish gray and well demarcated from the surrounding spinal cord, splaying the posterior columns laterally on each side (Fig. 4). A distinct plane between the mass and the surrounding cord was apparent circumferentially. Gross total resection was achieved, confirmed by ultrasound guidance during the resection.

Postoperatively, the patient had only transient left upper extremity paresis and recovered extremely well, regaining full strength in both upper extremities, with resolution of her preoperative symptoms and neurological deficits. The patient was transferred to an inpatient rehabilitation facility on postoperative day 6. Her impressive recovery persisted, with no evidence of lesion recurrence on a follow-up MRI obtained 2 months after surgery.

PATHOLOGICAL FINDINGS


Sections of the excised lesion showed oblique profiles of abnormal spinal cord elements with hypercellularity in the parenchymal and perivascular regions (Figs. 5, 6, 7, 8). An LFB-PAS stain (Fig. 9) showed sharply demarcated zones of myelinated and demyelinated axon fascicles. NF1 immunostain (Fig 10) confirmed that the long processes were axons, and were focally swollen and dystrophic. GFAP immunostain (Fig 11) documented widespread reactive piloid astrocytic processes and occasional gemistocytic reactive astrocytes in the parenchyma. CD68 immunostain (Fig. 12) highlighted columns of foamy macrophages interdigitating between the dystrophic and focally swollen neurofilament immunopositive axons. There were perivascular cuffs composed predominantly of CD3 positive T-lymphocytes (Fig. 13) with some CD20 positive B-cells (Fig. 14).

FINAL DIAGNOSIS


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