Ancient schwannoma of lumbar spine and review of the literature on paraspinal tumors, the role of preoperative biopsy: a case report

Abstract

Introduction: Schwannomas are rare encapsulated tumors that derive from the nerve sheath and should be removed due to their infrequent, but existent possibility of malignancy.

Case presentation: We report a case of a mass located in the L5 lumbar spine in a 42 year old man, presented with intermittent lumbar pain. Ultrasound, CT and MRI were used to examine the characteristics of the lesion. Fine needle aspiration showed cytologic characteristics of benign schwannoma and final histological diagnosis was ancient schwannoma. An extraperitoneal approach, through a left paramedian incision was used to approach the site of the mass. The lesion originated from the nerve root of the L4-L5 lumbar spinal space and a complete excision was achieved.

Conclusion: A great variety of tumors should be differentiated when a paraspinal mass is discovered, including neurogenic, neuroendocrine and vascular tumors, as well as malignancies, cystic and inflammatory masses. Fine needle aspiration is a useful and reliable tool in the preoperative evaluation of paraspinal masses. A review of the literature is also presented.

Figure 1

CT showing a 5 cm mass in the left lumbar paraspinal region, indicated by the arrow.

Figure 2

Abdominal MRI showing a well-defined encapsulated mass, in the left paraspinal region at the L5 level along the posterior side of left psoas muscle.

Figure 3

Lumbar spine MRI showing an encapsulated ovoidal retroperitoneal lesion in the L4-L5 level with scintigraphic uptake and cystic degeneration.

Figure 4

A, B: Cytologic views of schwannoma.

Figure 5

A: Hematoxylin-eosin stained sections (×40) reveal ancient schwannoma with circumscribed spindle-cell tumor, cellular atypia but no mitotic activity, myxoid degeneration, and vessels with hyalinized walls. b: Strongly positive S100 immunohistochemistry in ancient schwannoma.