Neuromuscular choristoma of the sciatic nerve in a child: description of clinical observation and brief literature review

The casuistry of benign triton tumor/neuromuscular choristoma (NMC) in the world medical literature has no more than 40–50 observations. There are no descriptions of a such disease in Russian sources. Here is our own case. A 6-year-old boy was diagnosed with a benign tumor of the right sciatic nerve. Sciatic neurolysis and removal of the neoplasm with a size of 8 × 3 × 3 cm were performed. Histological and immunohistochemical investigation revealed a tumor built of bundles of striated muscles and nerve fibers intertwined in the collagen matrix. Conclusion: benign triton tumor (NMC). NMC is an extremely rare neoplasm associated with large nerves and occurs more often in childhood. Pain syndrome/neuropathy is usually clinically registered. Although a mature triton tumor is considered benign, it often has recurrences and desmoid fibromatosis (mainly postoperative): it is assumed that trauma stimulates fibroblasts/myofibroblasts with a mutation of the CTNNB1 gene. For this reason, noncontact diagnosis is recommended for patients with classic clinical and radiological signs of NMC. To develop an optimal approach to the treatment of this tumor and to assess the long-term prognosis of the disease, it is necessary to accumulate a sufficient number of observations.