Schwannoma in an accessory branch of the posterior cord of the brachial plexus: a rare case report

Background: Variation in the posterior cord of the brachial plexus is complicated and creates a risky relationship with the neighbouring structures. This is of importance to the surgeons, anaesthetists who must deal with the region in surgeries and procedures. Moreover, any benign tumour like Schwannoma is rare in the plexus comprising 5 % of total head and neck schwannomas. Methods: We present a case of Schwannoma of the brachial plexus in a cadaver during routine anatomy dissection for the medical students. The origin and order of branching of the posterior cord were recorded and photographs were taken. The tumour was present in an accessory branch of the posterior cord and removal was made in-toto. An immunohistochemistry study was done for confirmation of diagnosis. Results: The classical branching of the posterior cord was present. Additionally, a branch existed that was supplying the triceps muscle and emerged directly from the posterior cord. Tumour having the dimension of 2 x 1.8x 0.5 cm was present. Conclusions: Schwannomas are indolent but may cause compression of the nerve and resulting neurological symptoms. They might mimic nodules of supraclavicular fossa in breast carcinoma. Variations of the brachial plexus can also make the surgeons confused during surgery due to which anatomical knowledge of the possible variations is important. Pre- and Post-operative complications can be easily predicted from it. Follow-up of the tumour is essential to track its progress and differentiation.