Fluid-fluid level in peripheral nerve schwannoma: report of a case with histological correlation.

Fluid-fluid level was observed in an unusual case of a 74-year-old man with peripheral nerve schwannoma of the lower extremity. To our knowledge, we found that schwannomas with imaging findings of fluid-fluid level had rarely been reported in the literature, and these tumors were all intracranial. Fluid-fluid level seen in peripheral nerve schwannoma has never been reported. In this case, MRI signal characteristics are those of blood and histological analysis of the fluid-fluid level suggests cystic degeneration with presence of intratumoral hemorrhage.