DISCUSSION
BAA is a rare vascular entity which can be broadly classified based on its localization into either mediastinal or intrapulmonary BAA [4]. Although all BAA can be found incidentally in patients with no symptoms, the latter frequently presents with hemoptysis. Mediastinal BAA on the other hand can present with a variety of symptoms resulting from extrinsic compression of contiguous structures including atelectasis, dysphagia, and superior vena cava syndrome [9]. Occasionally, the aneurysm may rupture, resulting in an acute and life-threatening condition characterized by chest pain, hemothorax, hemomediastinum, hematemesis, and shock [10].
In our case, the presenting symptom was unilateral periscapular pain, which is an atypical referring pattern for pain originating from the mediastinum. Although such a pattern has been demonstrated before in thymic carcinomas [11], lymphomas [12], or sarcomas [13] infiltrating the intercostal nerves, the pericardium, or vertebrae, such infiltration was not revealed on imaging in our patient. The viscerosomatic convergence theory might therefore provide a better explanation [14]. This theory states that noxious stimuli from a diseased organ can transmit to an adjacent normal structure, resulting in functional changes in the latter. This phenomenon is mediated by convergence of visceral and somatic afferent neurons at the level of the spinal cord, in lamina I and V of the dorsal horn, and results in afferent stimuli of the viscera being interpreted by the brain as dermatomal and sclerotomal pain. Viscerosomatic convergence might therefore be a possible mechanism of pain in patients presenting with BAA. In addition to the periscapular pain, our patient experienced shortness of breath, hoarseness, and dysphagia, all symptoms that are compatible with extrinsic compression of surrounding structures by the BAA.
In conclusion, we presented the case of a 60-year old woman with unilateral periscapular pain as an atypical presentation of three posterior mediastinal BAAs. The diagnosis was suspected based on chest X-ray and consequently confirmed on chest CT and selective bronchial arteriography. BAAs were removed successfully via thoracotomy, with excellent recovery and relief of the periscapular pain.