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What is A 4-year-old child presented with a solitary painless mass on the neck. The parents told that the mass would usually swell and become tender during the times of an upper respiratory tract infection. On examination, a smooth, nontender, fluctuant mass along the lower one third of the anteromedial border of the sternocleidomastoid muscle between the muscle and the overlying skin was observed. CECT neck was done. The above structure develops from due to failure of obliteration of: - and explain in detail?
This is a case of Branchial cyst. CT scan at the level of the hyoid bone reveals a large, well-defined, non-enhancing, water attenuation mass (m) on the anterior border of the left sternocleidomastoid muscle - suggestive of a branchial cyst. It arises from failure of obliteration of 2nd branchial cleft in embryonic development.