Large retroperitoneal schwannoma: a rare cause of chronic back pain

Abstract

Schwannomas are tumours that arise from Schwann cells of the peripheral nerve sheath and rarely occur in the retroperitoneum. We report a 45-year-old woman who presented with a 2-year history of continuous progressive right-sided lower back and dull flank pain radiating into her posterolateral thigh. Abdominal magnetic resonance imaging showed a homogenous soft-tissue tumour with thick capsular lining, which lay in the right retroperitoneum. The tumour was removed at surgery. A histological examination confirmed the diagnosis of benign encapsulated cellular schwannoma. Complete tumour excision should be regarded as the treatment of choice for benign retroperitoneal schwannomas. Successful treatment of these tumours requires thorough preoperative planning and a multidisciplinary approach.

Keywords: Benign retroperitoneal schwannoma; S100 protein; encapsulated mass; histological examination; lower back pain; magnetic resonance imaging; tumour.

Figure 1.

Magnetic resonance images showing a large, homogenous, soft-tissue tumour with a thick, smooth capsule in the right paravertebral retroperitoneum. This tumour displaces the iliopsoas muscle distally and the right kidney craniolaterally, without any signs of ipsilateral hydronephrosis and adjacent organ involvement.

Figure 2.

Histopathology of benign schwannoma. Spindle cells show a palisading arrangement with Verocay bodies formed by two parallel lines of nuclei and blood vessels. (A) Haematoxylin and eosin staining, ×10. (B) S100-positive cells, ×10. (C) The Ki-67 index was 1.6%, ×20.