Distal Leg Posterior Tibial Nerve Schwannomas Combined With Tarsal Tunnel Syndrome: A Case Series and Literature Review.

While the pathophysiology of space-occupying lesions inside the tarsal tunnel causing tarsal tunnel syndrome (TTS) is obvious, the occurrence of a posterior tibial nerve (PTN) mass outside the tarsal tunnel but mimicking or in combination with TTS symptomatology is less clear. Therefore, we report three rare cases of patients presenting with TTS symptoms combined with a distal leg PTN schwannoma, all of whom were treated with tumor resection and tarsal tunnel decompression. All patients had a long-lasting history of leg and ankle pain radiating to the medial aspect of the foot and toes. Pain was especially worsened at night, during walking, and with weight bearing. PTN schwannomas were located at the distal third of the leg. One patient was secondarily decompressed after previous tumor resection elsewhere. The surgical approach included tumor resection with fascicle-sparing enucleation and tarsal tunnel decompression with single or two incisions. Tumor resection was complete in all patients, and the diagnosis of schwannomas was confirmed by histological analysis. Transient-sensitive deterioration was documented in one patient, but there were no motor complications. The pain was resolved completely in two patients and partially in one patient at the last follow-up. PTN schwannomas mimicking or in combination with TTS make the diagnosis challenging since they share most of the clinical symptoms and signs. Such recognition is of utmost importance for better patient management. In these situations, tarsal tunnel decompression could be included in the surgical procedure to achieve long-lasting relief of pain.