RESUMO
Ganglion is a common benign tumor and is likely to cause paralysis of posterior interosseous nerve by compressiononce occurred in proximal radial area. A 25- year old female patient, who was suffering from forearm pain and trouble with extending her fingers after intramuscular stimulation, visited this hospital. We diagnosed as the common extensor muscle rupture by physical examination. But, on the basis of preoperative MRI, she was diagnosed with incomplete posterior interosseous nerve paralysis caused by ganglion of the proximal radius. We performed the surgical excision and obtained a satisfactory result without any evidence of recurrence at the 1 year follow-up after surgery. Incomplete compressive neuropathy of posterior interosseous nerve sometimes confused with spontaneous rupture of the common extensor muscle, which can lead to inappropriate surgical treatment. Careful preoperative examination is essential to avoid misdiagnosis. We report this case with review of the relevant literature, because of rarity of incomplete compressive neuropathy of posterior interosseous nerve by ganglion.