gms | German Medical Science

Objective: Intraneural perineuriomas are benign peripheral nerve tumors. Due to their rarity, only little information is available concerning their epidemiology and the management of these tumors. Currently, there are no diagnostic or treatment guidelines available. We illustrate six cases treated at our institution (from 1992 to 2010).

Methods: Case-guided retrospective analysis of six patients with intraneural perineuriomas. Illustration of the special imaging characteristics (MRI and ultrasound) and treatment aspects (in consideration of intraoperative electrophysiology and ultrasound) by means of one perineurioma of the median nerve and another from the brachial plexus.

Results: All patients were male. There were 5 tumors of the upper extremity (1 ulnar, 1 median, 2 radial, 1 brachial plexus) and one tumor of the lower extremity (common peroneal part of sciatic nerve). Since 2008 surgery was routinely performed after preoperative MRI, and pre- as well as intraoperative high-resolution ultrasound was also performed. Intraoperative ultrasound depicted a smooth transition from healthy looking fascicles to thickened fascicular structures with hypoechogenic swollen areas; those were up to three times thicker than fascicles in non-affected regions. Preoperative MRI, which displayed the tumor mass as hyperintensive in T2-weighted sequences, correlated very well with the intraoperative findings and was essential for surgical strategy. One patient underwent an epineurectomy and biopsy of the median nerve since the motor function of his hand was satisfactory, the other patient underwent tumor resection and reconstruction of the brachial plexus.

Conclusions: Intraneural perineuriomas are very uncommon peripheral nerve sheath tumors. Their treatment has been discussed controversially, since it is a benign, slow-growing lesion and the functional loss in most of the cases is incomplete. On the other hand, resection of affected fascicles with subsequent autologous reconstruction is the only curative treatment option. Surgical interventions such as biopsy, decompression, transplantation, split repair or wait-and-see are possible. Technical advances in MRI and ultrasound enables the surgeon to get an idea of tumor's expansion and increase. However, surgery still has some limitations. Resection is the only possibility to stop functional loss, but the right point of time must be chosen individually in each single case.