The difficulty to distinguish a branchial cleft cyst from a cystic metastasis is well known. Branchial cleft cyst is a benign condition which is treated by surgery with relatively low morbidity. Cancer of unknown primary has formerly been treated with neck dissection and then radiotherapy. We, like many head and neck cancer centers in the world, has in recent years relied on the cytological diagnosis of SCC (which can be hard) in combination with HPV analysis, and if the metastasis is HPV positive it is assumed that the primary tumor is in the base of tongue or the tonsils. Then the patient receives radiotherapy. The problem is that this shift in diagnostic and treatment has occurred, even internationally, without anyone really examined whether HPV can also occur in branchial cleft cysts. The risk is that if we rely on HPV assay as a diagnostic tool for cancer, even if branchial cleft cysts are found to be harboring HPV, patients with HPV positive branchial cleft cyst can receive uneccesary cancer treatment.
In a previous prospective study of FNAC in neck masses we found 18 branchial cysts which all were HPV-negative.1
All patients over 18 years who underwent surgery for branchial cleft cysts from 2005 to 2015, about 400 pc, is included. HPV assay is performed with Multiplex Luminex HPV PCR method in histological sections from paraffin-embedded material from 2005-2015 from the cyst surgically removed.
12 branchial cleft cysts have so far been analyzed, and they have all been HPV-negative.
Reliable methods for diagnosis of cystic lesions the neck is essential for proper diagnosis and treatment. There is, so far, not any published articles regarding HPV in branchial cleft cysts.
1. Human papillomavirus DNA detection in fine-needle aspirates as indicator of human papillomavirus-positive oropharyngeal squamous cell carcinoma: A prospective study. Volume 39, Issue 3, pages 419–426, March 2017, Sivars Lars, Landin David et al