Benign Paravertebral Ancient Neurilemmoma in a Young Adult: A Rare Occurrence

Abstract

A young adult male 21-year-old presented to our out patient department (OPD) with history of periumbilical pain of 6 months duration with no other associated symptoms. Examination revealed a vague, hard, globular, retroperitoneal mass, of 5x4 cm, in the left para-umbilical region extending into lumbar region, with lateral and superior borders palpable only on deep palpation. Ultrasonography of the abdomen showed an encapsulated well-circumscribed solid mass, measuring 6x4 cm, in the left para-aortic area, with homogenous density and two tiny areas of necrosis, suggestive of paragangliomaora lymph nodal mass. CECT abdomen reported a large,well-defined, lobulated soft tissue mass lesion measuring approximately 6.2x4.8x7.3 cm in the left para-aortic aspect of retroperitoneum at the level aortic bifurcation with extension along the left common iliac artery. It showed mild heterogeneous enhancement within the mass on contrast study with mild peripheral vascularity. The mass was closely abutting the abdominal aorta with infero-medial displacement of the left common iliac artery and lateral displacement of the mid portion of the left ureter. CT guided FNAC of the mass revealed spindle cell tumour of nerve sheath origin probably of benign nature. MRI Lumbo-Sacral spine [Table/ Fig-1,2] reported a large T1 hypo intense and T2 heterogeneously hyper intense, well-encapsulated retroperitoneal mass at the level of L4 vertebra representing nerve sheath tumour.Following these investigative findings, an exploratory laparotomy was performed with midline approach. A mass was noted in the left paracolic gutter covered by the sigmoid mesocolon. Peritoneal reflection from the lateral paracolic gutter along with sigmoid mesocolon was reflected medially off the mass, preserving the inferior mesenteric vessels. The mass measuring 7x 8 cm, was found stretching and displacing the left ureter and gonadal vessels on its lateral aspect [Table/ Fig-3a] and was closely abutting the lower 5cm of the aorta and displacing the left common iliac vessels inferiorly [Table /Fig-3b]. The above structures were densely adherent to the capsule of this mass. These structures were meticulously dissected and preserved. One lumbar spinal nerve was found entering the mass postero-superiorly, which was divided. The entire mass was excised with the capsule intact and sent for histopathological examination.Gross examination revealed a well-circumscribed tumour with solid and cystic areas and calcific foci. Histopathologic examination aBstRaCt Neurilemmoma is a benign neurogenic tumour arising from Schwann cells of the peripheral nerve sheath, which is commonly seen in women in the 5 th decade. It rarely arises in the retroperitoneum, being more common in the head and neck region and extremities. Ancient variety of schwannoma is a long-standing tumour, is seen in the middle age and elderly age groups, and is associated with secondary degenerative changes. Herein, we report a case of benign retroperitoneal paravertebral ancient neurilemmoma occurring in a young m...