[Are lateral neck cysts true derivatives of cervical lymph nodes?]

For decades the origin of the branchial cyst has been attributed to an abnormal involution of derivatives of the second branchial cleft. More recently the cyst has been thought to be the result of tonsillitis and lymphadenitis, stimulating a lymphatic spread of squamous epithelium from the tonsil to the regional lymph nodes. We reviewed the histopathologic reports of 81 branchial cysts and 19 fistulas and re-examined 30 cysts and 5 fistulas by light microscopy. Similarities of morphological features between the epithelium of tonsillar crypts and of the branchial cysts were striking and emphasize the close relationship of the tonsils (2nd branchial pouch) to branchial cysts and fistulas. These observations and a review of the literature support the well-known branchiogenic origin of branchial cysts.