We report a rare case of primary thoracic rhabdomyosarcoma in a girl who wa
s referred with acute chest pain, hacking cough, and wheezing. A chest X-ra
y revealed a complete opacity of the right hemithorax. Ultrasound revealed
a right-sided pleural effusion and a solid mass above the liver dome, sugge
sting a neoplastic disease, which quickly led to further specific examinati
on. Use of CT and MRI together with bone scintigraphy completed the investi
gation. The biopsy specimen showed a pattern of alveolar rhabdomyosarcoma.
This case was reported to emphasize the role of US in the evaluation of a c
hild with hemithorax opacity.