Background: Branchiogenic carcinoma is defined as a malignant degeneration within the confines of epithelial remnants derived from the embryonal branchial apparatus. The importance of this entity is
in the differential diagnosis with a cervical metastasis from a carcinoma of unknown primary
site (CUP- syndrome). The objectives are to familiarize the clinician with the presentation and
treatment of cystic metastases from head and neck primary sites and to differentiate these from
primary branchial cleft cyst carcinomas. The principal diagnostic criterion for lateral cervical
cyst carcinoma is the histopathologic demonstration of transitional areas from benign epithelium
into invasive squamous cell carcinoma. The modified criteria of Khafif (1989) are those used in
diagnosing branchiogenic squamous cell carcinoma.
Case Report: We present a case of a 52-year-old patient with a 2-month painful mass in the right cervical region. A complete tumor excision was performed. The histopathologic diagnosis of the lesion
was branchial cleft squamous cell carcinoma.
Conclusions: The diagnosis of a primary branchial cleft cyst carcinoma requires the fulfillment of strict criteria. All criteria proposed by Khafif (1989) were met in our case.

Keywords: neck mass, cystic metastasis, branchial cleft cyst carcinoma, lateral cervical cyst, occult primary