Retrospective Analysis of 20 Patients With Schwannomas: Magnetic Resonance Imaging Characteristics, Pain, and Outcomes Following Excision

Abstract

A Tinel's sign, a percussion-induced, painful sensation, has been reported as the most useful sign for diagnosing a schwannoma. On magnetic resonance imaging, schwannomas often exhibit a split fat sign and a target sign. The typical treatment for schwannomas is surgical excision; however, excision often results in high rates of neurological deficit. The authors retrospectively reviewed 20 patients who underwent excision of a schwannoma from 2007 to 2015. Twenty patients presented with a split fat sign and 12 patients presented with a Tinel's sign on magnetic resonance imaging. Only 3 patients presented with a target sign on magnetic resonance imaging. The operative approach involved removing the schwannoma, preserving the nearby nerve fascicles, and leaving the epineurium open. Follow-up ranged from 3 to 91 months (average, 29 months). At final follow-up, all patients were pain free. Nineteen patients had normal sensation and full function of their affected limb. One patient developed postoperative posterior interosseous nerve palsy. A Tinel's sign, preoperative pain, and a split fat sign on preoperative magnetic resonance imaging are the clinical symptoms most useful for diagnosing a schwannoma. Schwannomas can be safely removed via intracapsular surgical excision with minimal complications, yielding eradication of preoperative pain, normal sensation, and full function. [Orthopedics. 2017; 40(6):e1036-e1043.].

Comparison of ultrasonographic findings of schwannomas and angioleiomyomas

“…Regarding our ultrasonography findings, a few previous studies have reported ultrasonography findings of each tumor . However, there is no report comparing the differences between angioleiomyomas and schwannomas using ultrasonography.…”

“…On T 2 ‐weighted images, the central portion of the mass (Antoni A) displays a low to intermediate signal relative to the surrounding tissue, while the peripheral ring (Antoni B) displays a high signal intensity; hence, this imaging feature is referred to as a “target sign”. However, Hooper et al . reported that only three of 20 (10%) patients displayed a target sign on MRI.…”

“…Regarding our ultrasonography findings, a few previous studies have reported ultrasonography findings of each tumor. 4,14,15 However, there is no report comparing the differences between angioleiomyomas and schwannomas using ultrasonography. In this study, we attempted to identify additional and significant differentiating features to distinguish between both, using sonography ( Fig.…”

“…A subcutaneous tumor accompanied by tenderness can have diverse differential diagnoses, such as angiolipoma, angioleiomyoma, schwannoma, glomus tumor and eccrine spiradenoma. [1][2][3][4] In the clinical practise setting, subcutaneous tumors are differentiated by the patient's age and sex, their clinical course and physical findings, including the size and location of the tumor, and the presence or absence of accompanying pain. In most cases, it is possible to narrow the differential diagnoses using clinical information.…”

“…A subcutaneous tumor accompanied by tenderness can have diverse differential diagnoses, such as angiolipoma, angioleiomyoma, schwannoma, glomus tumor and eccrine spiradenoma …”