Cystic metastasis from head and neck squamous cell cancer: A distinct disease variant?

Background. Head and neck squamous cell carcinoma (HNSCC) commonly spreads to regional deep cervical nodes. In most cases, these metastases present as firm, solid masses in the designated lymph node chains. A distinct subset of metastatic nodes present as cystic masses, with most of the volume made up of a liquid center surrounded by a thin solid rim. It has been observed that certain squamous cell carcinoma (SCC) subsites are more likely to produce metastases that are cystic. These sites predominantly include primary tumors of tonsil tissue from Waldeyer's ring. In the past, these cystic cancers often have been erroneously diagnosed as branchiogenic carcinomas, that is, a branchial cleft cyst that has undergone malignant degeneration. Today, most authors have concluded that so-called branchiogenic carcinomas are actually cystic metastases in the neck probably arising from an oropharyngeal primary SCC. The purpose of this work is to consider the phenomenon of cystic lymph node metastasis in head and neck cancer in depth. Methods. A review of the relevant English-language literature linking cystic metastasis and head and neck cancer was performed. Results. These studies indicate that lateral cystic masses in adults often represent an occult primary cancer originating in the epithelium within Waldeyer's ring. Conclusions. Adult patients who are initially seen with a lateral cystic neck mass must be presumed to have a cancer until proven otherwise. The mass should be biopsied by fineneedle aspiration (FNA). However, negative FNA findings may be misleading; therefore, an excisional biopsy and examination under anesthesia with directed biopsies of Waldeyer's ring and bilateral tonsillectomy should be considered a part of the diagnostic workup.