Paraspinal Ancient Schwannoma of the Dorsal Ramus Nerve: A Case Report

ABSTRACT

STUDY DESIGN: Case report. OBJECTIVES: We report a case of paraspinal ancient schwannoma located at the upper thoracic level that mimicked an atypical lipoma or complicated epidermoid cyst. SUMMARY OF LITERATURE REVIEW Few case reports of paraspinal schwannoma have been reported and the incidence of ancient schwannoma in the paraspinal muscle layer is very rare. MATERIALS AND METHODS: A 39-year-old man complained of a growing palpable back mass for 5 years. He experienced aggravated chronic discomfort around the mass while lying down. Both T1- and T2- weighted magnetic resonance imaging (MRI) showed a well-capsuled and heterogeneous high-signal mass in the muscle layer at the level from the T1 to T4 vertebral bodies on the right side of the midline. The tumor was completely removed by en bloc resection. RESULTS: The pathologic examination revealed S-100 protein expression with degenerative changes. The lesion was diagnosed as an ancient schwannoma. CONCLUSIONS: Schwannoma is one among the multiple possible causes of benign back masses. If a mass reveals a well-encapsulated heterogeneous mass on contrast MRI, a schwannoma should be suspected.