Neurofibroma involving obturator nerve mimicking an adnexal mass: a rare case report and PRISMA-driven systematic review

Abstract

BackgroundPelvic masses are a common gynecologic problem, and majority of them are diagnosed as ovarian tumors finally. Sometimes, it is hard to distinguish the origin of these pelvic masses. The following case is a solitary neurofibroma arising from the right-side obturator nerve, which was impressed as a right-side ovarian tumor initially. We reported this case, and also performed a PRISMA-driven systematic review to summary the similar cases in the literature. This review includes image, molecular and pathological findings and outcome of neurofibroma.Case presentationA 33-year-old woman with a regular menstrual period denied any symptoms or signs. During her physical check-up, image examination revealed a right-side heterogeneous pelvic mass; it was suggestive of a complex of right-side ovarian tumor. A provisional diagnosis of retroperitoneal pelvic mass, probably a benign ovarian tumor, was made.Excision of the right-side pelvic mass was performed. We sent the specimens for frozen pathology, which indicated neurofibroma and lipomatous tumor and that the possibility of liposarcoma cannot be excluded. A segment of the obturator nerve was attached to the tumor and was severed. A right-side obturator nerve tear during tumor excision was observed, and a neurosurgeon was consulted for obturator nerve grafting and repair. The patient complained of mild weakness and paresthesia affecting the right leg, and we consulted a rehabilitation doctor for neuron injury. The patient’s recovery was uneventful, and she was discharged eight days after the drain was removed. Further rehabilitation treatment was arranged.ConclusionA neurofibroma is an uncommon pelvic retroperitoneal tumor, and it can be misdiagnosed as an adnexal mass. To our knowledge, this is a rare case of a solitary neurofibroma arising from the obturator nerve. It usually does not have any neurological deficit. We present this case to demonstrate that pelvic neurofibroma can be mistaken for an adnexal mass. This fact should be borne in mind during the diagnosis process.

Novel technical modifications of hand‑assisted laparoscopic dissection of a large obturator mass: A case report and literature review

“…The reasons are as follows: i) The combination of sharp and blunt dissection of the tumor causes injury to the nerve, as it is situated in close proximity to the tumor; ii) tumor tissue may be dissected along with the obturator nerve, irrespective of whether the nerve is infiltrated by the tumor; iii) pelvic lymph node dissection may cause injury. It is noteworthy that caution should be taken intraoperatively to protect the nerve against mechanical and thermal injury; in addition, the treatment process should include close observation of perioperative symptoms and signs, postoperative follow-up and neurotrophic support (1,3).…”

“…Obturator masses have a certain probability of occurrence in pelvic tumors. The most common origins of obturator masses are neurological tumors, including schwannoma and neurofibroma (1)(2)(3). Local tumors around the lateral obturator zone have been reported to be potentially resectable by laparoscopic lateral pelvic tumor dissection (LLPTD) (4).…”

Imaging in gynecological disease (26): clinical and ultrasound characteristics of benign retroperitoneal pelvic peripheral‐nerve‐sheath tumors

“…Patients with a schwannoma or neurofibroma are usually asymptomatic, with the mass being discovered as an incidental finding. The main symptoms are non-specific, such as vague abdominopelvic pain, bowel or urinary compressive symptoms, a palpable abdominal mass or neurogenic dysfunction 4,5,11 .…”

Retroperitoneal solitary neurofibroma mimicking lymph node metastasis of colon cancer: a case report

“…The exact pathogenesis of a solitary neurofibroma remains unclear and genetic studies of neurofibromas in the literature are scarce. The identification of genetic aberrations in these tumors are not expected to play a role in diagnosis [ 17 ].…”

“…Aggressive resection was needed for the retroperitoneal tumor because it co-occurred with other malignant tumors. Eleven cases of solitary retroperitoneal neurofibromas are listed in Pubmed (Table 2 ) [ 8 , 9 , 13 , 17 , 23 – 29 ] and no cases were diagnosed preoperatively. Mean age is 47.5 years old (33–73 years old) and mean tumor size is 127.5 mm (45–500 mm).…”