Hydatidosis of bone is rare. Vertebral localizations predominate. Standard imaging may be misleading, suggestive of a malignant tumor or infection. We present the case of a patient with a humeral hydatid. This localization is very rare and presents an unusual radiographic aspect. Computed tomography produces an image suggestive of a tumor. The correct diagnosis can be established with MRI, particularly with the STIR sequence. In our patient, MRI enabled us to establish the diagnosis preoperatively and evaluate extension. MRI has been found to be highly contributive to the diagnosis of hydatidosis of bone and for assessment of intra- and peri-osseous extension.