Multiple Schwannomas Involving an Unusual Communicating Loop between the Ulnar and Median Nerves in the Axilla: Clinical Implications

Background: Schwannoma and neurofibroma constitute benign peripheral nerve sheath tumors (BPNSTs), which may present as single or multiple lesions. Multiple schwannomas are rare in the peripheral nerves of the upper extremity. Solitary small schwannoma is usually asymptomatic, while larger and multiple schwannomas may have different symptoms due to pressure effects. Median and ulnar nerve communications are often encountered in the upper limb, making these anastomoses clinically important. However, such communications with schwannomas in the axilla are rare. Case Report: The study protocol was designed per the prevailing guidelines of the Institute on the use of human cadavers for teaching and research. Written informed consent was obtained from the family of the body donor at the time of whole-body donation. The upper extremities, including the brachial plexuses of both sides, were carefully dissected as per the instructions in Cunningham’s Manual of Practical Anatomy15th edition. Discussion: Unusual anastomoses in the axilla and two encapsulated, highly vascular fusiform masses were observed. Another fairly large mass was noted on the right chest wall. Histological examination confirmed the masses to be schwannomas. Conclusion: Asymptomatic schwannomas often remain undiagnosed, and those lying in the axilla can be misdiagnosed. Awareness of such variant anatomy will enable clinicians and surgeons to plan more appropriate diagnostic and therapeutic interventions.