The authors report a case of right-sided complete Pancoast and Tobias syndrome related to a multivesicular extrapleural hydatid cyst developing at the cervico-thoracic area with involvement of the first rib. This occurred in a 27 year old country dweller who was a non-smoker who presented with a progressive history of right sided cervico-brachial neuralgia some four months before hospitalisation, there was a subclavicular tumour swelling (8-10 cm), solid, non-inflammatory and a right sided Claude-Bernard-Horner syndrome. Screening of the thorax showed an opacity at the right apex, dense and homogeneous, with a pseudo-fracture of the first right rib. A cervical echo showed a multiloculated liquid filled mass without connection to the thyroid. Computer tomographic scanning showed a multiloculated voluminous liquid filled mass in the right cervico-thoracic area with a regular polycyclic outline, the lungs were normal. The serology was positive for hydatid disease (haemagglutination and ELISA). The patient was operated on by an exclusively supraclavicular approach with excision of the hydatid membranes and vesicles as well as the right first rib. The immediate outcome resulted in the disappearance of the neuralgia and the persistence of the Claude-Bernard-Horner syndrome.