A giant solitary schwannoma of the arm mimicking cyst hydatid.

We present a 77-year-old female with a size of 9.5×9×7 cm3 giant schwannoma of musculocutaneous nerve volarly located in midarm, which was misdiagnosed as cyst hydatid on ultrasonographic and magnetic resonance image examination. There was not any neurologic sequele after the operation. In case of the similarity of their clinical and radiological findings, schwannoma should be included in the differential diagnosis of hydatid cysts especially in endemic countries.