Brachial plexus neuropathy by hibernoma compression: An unusual presentation of peripheral non-neural sheath nerve tumor and a systematic review of literature

Brachial plexus neuropathies are uncommon and are rarely caused by a tumor. The clinical presentation of a brachial plexus neuropathy caused by a tumor depends on the degree of malignancy of the tumor and its localization. We report an illustrative case of a 27-year old female subject with a progressively increasing mass lesion causing brachial plexus compression, ipsilateral shoulder pain, C8 dermatomal paresthesia, and impairment of motor power. The patient underwent surgical resection of the mass and neurolysis of the nerves in the vicinity. Following the surgical procedure, the patient had improvement in the pain and paresthesia that he was suffering from. The histopathological diagnosis revealed a hibernoma, an extremely rare tumor described only once previously in this location. A systematic review of the literature was performed utilizing the PubMed database to access articles published before March 2018, using: A -the term 'hibernoma' in the title/abstract associated with the following MeSH terms: brachial plexus neuropathies OR brachial plexus neuropathy OR nerve compression syndrome, OR brachial plexus; B -the MeSH term 'brachial plexus' associated with the term 'non neural sheath nerve tumor' or 'peripheral non-neural sheath nerve tumor'. The origin of the hibernoma, as well as its metabolic influence, pathology, and treatment have been discussed.