Abstract. Giant intrapelvic malignant peripheral nerve sheath tumors arising in the sciatic nerve in the pelvic cavity are a rare occurrence and their symptomatology is usually misdiagnosed as intervertebral disc herniation. We herein report the case of a 46-year old woman presenting with pain, hypesthesia and weakness of the left lower extremity due to a giant intrapelvic malignant peripheral nerve sheath tumor of the sciatic nerve. Prior to being referred to our institution, the patient was misdiagnosed as a case of sciatica due to a lumbar disc herniation and underwent an operation unsuccessfully, as there was little symptomatic improvement 2 months after the surgery. A magnetic resonance imaging examination of the pelvic cavity revealed a tumor of the sciatic nerve. The mass was resected via the posterior approach and histopathological examination confirmed the diagnosis of malignant peripheral nerve sheath tumor. Intrapelvic malignant peripheral nerve sheath tumors are an uncommon cause of sciatica and are commonly misdiagnosed as lumbar intervertebral disc herniation. Accurate diagnosis and complete surgical excision prior to metastasis are crucial for effective management of this condition.
IntroductionThe most common cause of sciatica is intervertebral disc herniation; thus, obscure causes are rarely considered in the differential diagnosis. Malignant peripheral nerve sheath tumor (MPNST) arising from the sciatic nerve is a relatively rare malignant soft tissue tumor (1). This tumor may produce severe radicular pain and sensorimotor deficits, mimicking a disc herniation. Due to the rare incidence of this disease, reports on intrapelvic MPNSTs are scarce and there has been no systemic study of intrapelvic MPNSTs to date (2,3). In this study, we reported a misdiagnosed case of giant intrapelvic MPNST of the sciatic nerve mimicking disc herniation. Our aim was raise awareness that intrapelvic MPNST is an unusual cause of sciatica, which is usually misdiagnosed as disc herniation. The diagnosis, treatment and prognosis of MPNSTs were also discussed.
Case reportA 46-year old woman was admitted to another hospital with a 3-month history of pain that radiated from the posterior aspect of the left thigh to the lateral aspect of the leg and left foot, and was associated with numbness of the left lower limb. The patient had undergone a lumbar magnetic resonance imaging (MRI) examination, which revealed a mild L4/5 intervertebral disk herniation (Fig. 1A and B). A clinical diagnosis of intervertebral disk herniation was made, and L4/5 discectomy was performed (Fig. 1C and D). However, there was little symptomatic improvement after 2 months. The patient was subsequently referred to our institution.On admission, the patient's neurological examination revealed grade 3/5 weakness of the quadriceps femoris, grade 2/5 weakness of the triceps surae and grade 0/5 weakness of the extensor hallucis longus and extensor digitorum longus, a decreased sensation to light touch, decreased patellar reflex and Achilles reflex on the...