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Neurothekeoma of the Cauda Equina 2011

General Spine

Asif, Abdullah, M.D.
Hassan, Semaan, M.D., Non ASSR Member
Kristan, Jenkins-Mosure, M.D., Non ASSR Member
Haitham, Elsamaloty, M.D., Non ASSR Member
Terrence, Lewis, M.D., Non ASSR Member

Excerpta

Neurothekeomas are distinctive benign predominantly cutaneous tumors that most often occur in the skin of the face and arms of young adults. Intraspinal neurothekeomas are extremely rare. We report CT Myelogram and MR imaging findings of an extremely rare case of neurothekeoma of the cauda equina, which is a very unusual tumor of probable nerve sheath origin.

Purpose

To report an extremely rare case of intraspinal neurthekeoma.

Methods & Materials

We describe MR and CT Myelogram findings of an intraspinal neurothekeoma occurring in a 49 year-old white female who presented with back pain.

Results

A 49-year old white female presented with severe low back pain radiating into right hip and leg for one month. Patient also had complains of numbness and tingling in her right leg. The pain was exacerbated by activity. She had some difficulty initiating micturition. Physical examination revealed a flexed posture. No additional abnormalities were illicited. Laboratory values were within limits of normal. MR imaging of the lumbar spine was performed which showed a well-circumscribed intradural extramedullary mass at the L1-L2 level which measured 2.1cm x 1.3cm x 1.3cm nearly filling the entire thecal sac with mass effect on adjacent nerve roots. It showed predominantly high signal on T2W imaging (Figs.1B & 2A) with internal areas of low signal intensity and isointense signal to muscle on T1W imaging (Figs. 1A & 2C). Post contrast enhanced T1W MR images showed avid enhancement (Figs. 1D & 2D) with subtle areas of internal non-enhancement (Fig. 1C). Differential considerations at this point included an epyndymoma, schwanoma, neurofibroma, and paraganglioma. Neurosurgical consultation requested a preoperative CT Myelogram examination which demonstrated a well circumscribed soft tissue density mass at L1-L2 level filling the thecal sac with small rim of intrathecal contrast along the periphery of the mass (Figs. 3A & 3B). Gross analysis of the lesion showed a dark brown and tan mass with smooth consistency. Microscopically, tumor demonstrated a lobulated appearance with a peripheral capsule. The lobules were primarily composed of delicate spindle cells separated by a myxoid matrix. In addition to the myxoid nodules, areas of spindled cells without myxoid change and areas of loose stellate cells were seen. There was no convincing palisading of tumor cells. Ultrastructural examination showed long, intertwined cell processes lined by basal lamina, and numerous Luse bodies. These findings were consistent with a mixed cellular and myxomatous form of neurothekeoma. Patient remained asymptomatic at 6-month and 2-year clinical follow-up without evidence for recurrence on MR imaging follow-up

Conclusion

Intraspinal neurothekeomas mimic ependymoma, schwanoma, and paragangliomas in radiologic appearance and may be included in the differential diagnosis of soft-tissue masses of cauda equina. Clinically, neurothekeomas exhibit benign behavior and are successfully treated in most cases with complete excision. Local recurrence is extremely uncommon when there are wide surgical margins Additionally, neurosurgeons and neuroradiologists should be familiar with the benign nature of these masses.

References/Financial Disclosures

Kim H-J, Baek CH, Ko YH, and Choi JY. Neurothekeoma of the Tongue: CT, MR, and FDG PET Imaging Findings. Am J Neuroradiol. 2005; 27:1823â