Imaging of ancient schwannoma.

Abstract

We surveyed the clinical symptoms and radiologic features of ancient schwannoma, a rare variant of schwannoma characterized by degenerative changes. We present the clinical, radiologic, and pathologic features in seven patients with ancient schwannoma (mean age, 62 years; range, 45-80 years) treated at our department between 1998 and 2003. The most characteristic clinical features were a sign like Tinel's sign and a long interval between the onset of symptoms and surgery (mean interval, 8.3 years). Ancient schwannomas can grow large; the biggest tumor seen in our study was 14 cm long. The highly accurate radiologic assessment made possible with contrast-enhanced MRI and CT scanning showed enhancement at a peridegenerative area and sometimes at a capsule. These findings differ from those of the typical schwannoma and neurofibroma patterns reported to date. Furthermore, bone scintigraphy showed uptake in the tumor, but no accumulation was seen on gallium-67 citrate scintigraphy. The characteristic clinical and radiologic findings of ancient schwannoma should make it possible to differentiate it from malignant tumors.