The authors present the guidelines of the French Society of Otorhinolaryngology - Head and Neck Surgery Society on diagnostic procedures for lymphadenopathy in case of a cervical mass with cystic aspect.

A multidisciplinary work-group was entrusted with a review of the scientific literature on the topic. Guidelines were drawn up, then read over by an editorial group independent of the work-group, and the final version was drawn up. Guidelines were graded as A, B, C or expert opinion, by decreasing level of evidence.

In adults presenting a cystic cervical mass, it is recommended to suspect cervical lymphadenopathy: in order of decreasing frequency, cystic metastasis of head and neck squamous cell carcinoma, of undifferentiated nasopharyngeal carcinoma, and of thyroid papillary carcinoma (Grade C). On discovery of a cystic cervical mass on ultrasound, architectural elements indicating a lymph node and a thyroid nodule with signs of malignancy should be screened for, especially if the mass is located in levels III, IV or VI (Grade A). Malignant lymphadenopathy should be suspected in case of cervical mass with cystic component on CT (Grade B), but benign or malignant status cannot be diagnosed only on radiological data (CT or MRI) (Grade A), and 18-FDG PET-CT should be performed, particularly in case of inconclusive ultrasound-guided fine needle aspiration biopsy (Grade C).