Posterior interosseous nerve palsy caused by a parosteal lipoma seated over the proximal radius; a case report and review of the literature

Abstract

Several different pathologies may play a role in the etiology of posterior interosseous nerve (PIN) palsy such as trauma, radial tunnel syndrome, tumors, vasculitis, septic arthritis, and rheumatoid synovitis. The most common atraumatic factor is the compression of the nerve through its anatomic path. Parosteal lipoma around the proximal radius is the leading solid tumor seen among the neoplastic lesions. Although it is common, there are only case reports or few case series reported in the current literature and a comprehensive review is missing. Herein a rare case of PIN palsy due to parosteal lipoma of the proximal radius is presented together with a thorough literature review. A 48-year-old woman was presented with elbow pain and wrist drop that lasted for ten months. Electrodiagnostic and imaging findings lead to a diagnosis of PIN palsy due to parosteal lipoma seated over the proximal radius. Total surgical excision was performed, and the patient had been followed up for one year. Removal of the lipoma failed to recover the patient's symptoms. We reviewed all the reported cases and discussed, epidemiology, clinical findings, imaging studies, electrodiagnostic studies, pathology, treatment and prognosis of PIN palsy due to parosteal lipoma.

Posterior interosseous nerve entrapment due to bilobed parosteal lipoma

“…Even though MRI is the imaging modality of choice for these conditions, skiagrams may reveal a soft tissue radiolucent area consistent with a lipoma. 6,7 In our case plain radiographs were found to be normal.…”

“…Some studies have advocated use of anterior approach for excision of these lipomas. 7,8 However, we didn't find any difficulty using posterior approach. Regardless of the incision and approach, the aim of the surgery should be meticulous en bloc excision of the mass without causing iatrogenic damage to PIN.…”

“…5 However, cases have also been reported where excision of the mass failed to result in functional recovery and required tendon transfer. 7 If surgery is delayed for about 18 months, it is more likely that fibrosis of the affected muscles will occur. In such cases tendon transfers become the only viable option for achieving functional restoration.…”

Posterior interosseous nerve entrapment by intramuscular lipoma arising from the supinator muscle - a case report

“…There is an agreement among surgeons that the recovery of the nerve function depends mainly on the duration of symptoms, and early surgical decompression will offer faster recovery and better functional outcomes [1,9]. However, despite the success of lesion surgical excision to provide PIN full recovery, in some cases, even with early surgical intervention, full recovery was not gained, requiring further tendon transfer [10]. Vikas et al suggested that surgical decompression delay beyond 18 months may lead to fibrosis of the muscles innervated by the PIN, increasing the chance for further tendon transfer to gain accepted functional outcomes [1].…”

“…The approach used for surgery should offer a wide exposure and a safe window to perform dissection and excision of the mass for the safety of the neural structures. We used the anterior approach for excising the mass, which was recommended in previous studies, as it offered better visualization and access to the lesion, and better use of the anterior approach for excising these lesions [5,8,10]. However, in their case report, Vikas et al used the posterior approach to access a parosteal bilobed lipoma, and they reported excellent visualization of PIN and its branches, which guarded against iatrogenic injury nerve during dissecting and excising the lesion [1].…”