Radiology Grandrounds-XXVII

Here is a case of unusual branchial cyst for the Radiology Grand Rounds submitted by Dr MGK Murthy and Dr Sumer Sethi of Teleradiology Providers. Concept and Archive of the Radiology Grand Rounds is available at- Radiology Grand Rounds

As per King’s criteria any cyst arising outside the midline of the neck and having lymphoepithelial characteristics should be regarded as a branchial cyst. Such cysts are found more commonly in females and usually occur in the 2nd or 3rd decade of life. They are most commonly found in the anterior triangle of the neck anterior to the upper third of the sternomastoid. A cyst occupying the posterior triangle is extremely rare. However these cysts have been reported to occur in all the regions of the neck, and even in the mediastinum and the abdomen. Hence they should be suspected in all the cystic swellings of the neck except the median ones. Ultrasonography and FNAB definitely help in arriving at the diagnosis and is especially recommended for patients in the older age group to rule out cystic secondaries from head and neck malignancies. On operation a unilocular cyst with clear fluid, deep to the investing fascia and without a connecting stalk more or less makes the diagnosis certain. The histological picture is classical and confirmatory.The ‘Branchial theory’ has now fallen into disfavour and the most appropriate hypothesis explaining the aetiology of these cysts is the "Lymph node inclusion theory" with he palatine tonsils as the most likely source of the enclosed epithelium.Complete surgical removal remains the only acceptable form of treatment. The first branchial cleft develops into the external auditory canal. The second, third, and fourth branchial clefts merge to form the sinus of His, which will normally become involuted. When a branchial cleft is not properly involuted, a branchial cleft cyst forms. Occasionally, both the branchial pouch and branchial cleft fail to become involuted, and a complete fistula forms between the pharynx and skin

First type-1- near tragus and type 2 near submandibular gland

Second Branchial-most common(95%) near outer border of strenocleidomasotid

Third-rare , posterior and enters larynx

Fourth-goes along reccurrent laryngeal nerve and can go anywhere in to mediastinum

Dr.Sumer K Sethi, MD

Sr Consultant Radiologist ,VIMHANS and CEO-Teleradiology Providers

Editor-in-chief, The Internet Journal of Radiology

Director, DAMS (Delhi Academy of Medical Sciences)