Fibrous connective tissue lesion mimicking a vestibular schwannoma: case report

Cerebellopontine angle fibromas are rare pathological entities that can mimic the presentation of vestibular schwannomas (VSs). Diagnosis of these benign lesions, however, is important, because treatment options may be different. The clinical, radiological, and intraoperative features of these unusual lesions of the cerebellopontine angle are discussed, with review of the relevant literature.

A 41-year-old man presented with recurrent episodes of diminished hearing on the left side, accompanied by facial ticks and pain on the same side. Magnetic resonance imaging and computed tomographic scans revealed a 1.5-cm, primarily intracanalicular lesion, suggesting a left VS.

The lesion was partially removed through a retrosigmoid suboccipital craniotomy. Its intraoperative appearance and hard fibrotic consistency differed from the classic features of VSs. The pathological findings indicated nontumoral fibrous connective tissue. The lesion exhibited no features of inflammation or fat and was also negative for S-100 staining. Follow-up magnetic resonance imaging scans demonstrated a small residual lesion, which exhibited shrinkage in subsequent magnetic resonance imaging studies. The painful ticks disappeared and facial nerve weakness improved postoperatively.

Although cerebellopontine angle fibromas may present similar radiological features, their clinical presentation may be somewhat different from that of typical VSs. If a fibroma is suspected, radiosurgery should be avoided; limited surgery may be considered as an option for patients experiencing symptoms. Because fibromas may be intraoperatively noted to be fibrotic and vascular, radical removal may not be easy or justified. After the final diagnosis has been reached, conservative treatment of the residual lesion may be the best option.