Hiroshi Ito*,Tsukasa Isago,Junji Hishiyama
We presented a rare case of schwannoma arising from the rectus abdominis muscle in a 26-year-old woman. She had referred to our department with a complaint of painless swelling on the right side of the umbilical region. The mass was about 4 cm in diameter, flat, elastic, and immobile. Ultrasonographic examination revealed a 37×30 mm cystic lesion in the right rectus abdominis muscle and showed a heterogeneous low-echo area within the cyst. Magnetic resonance (MR) imaging examination of the abdomen showed a low-intensity in T1-weighted imaging, and T2-weighted images indicated niveau formation of a high-intensity area and a low-intensity area. With these findings, the patient was scheduled for surgery. Surgical specimen was 3×2.5 cm surface-flat cystic tumor containing bloody fluid, and pathological diagnosis was schwannoma associated with cystic degeneration. This is the first case, to our knowledge, of schwannoma arising in the rectus abdominis muscle.