THE CLINICAL IMPORTANCE OF CYSTIC SQUAMOUS-CELL CARCINOMAS IN THE NECK - A STUDY OF 136 CASES

BACKGROUND, Predominantly cystic squamous cell carcinomas in the neck often present without a clinically apparent primary and therefore are frequently considered to be of branchial cleft origin. It is the autho rs' hypothesis that the anatomic site of the primary carcinoma that pr oduced the neck metastasis can often be predicted on the basis of the histologic features. METHODS. Cases of cystic squamous cell carcinoma in the neck diagnosed between 1971 and 1991 were retrieved from the Ot orhinolaryngic Pathology Registry of the Armed Forces Institute of Pat hology. Histologic features were reviewed and patient follow-up was ob tained and analyzed. RESULTS. In cases wherein the primary site was di scovered subsequently, 64% of the primaries were in the lingual or fau cial tonsil. An additional 8% of cases were in nasopharyngeal tonsilla r tissue. The cases that did not originate in Waldeyer's tonsillar rin g generally differed in histologic appearance from the tonsillar cases . The tonsillar primaries were discovered within an average of 12.4 mo nths, but many were not discovered for years (up to 11 years). Most we re small, indicating a slower growth of the primary than is usually ex pected for squamous cell carcinoma. Patients with such carcinomas had a much better prognosis than patients with metastatic squamous cell ca rcinomas of other upper airway mucosal sites. CONCLUSIONS. In most cas es of prominently cystic squamous cell carcinomas in the upper neck, t he origin of the primary site will be in faucial or lingual tonsillar crypt epithelium. Knowledge of the probable site of origin allows for more tailored therapy in which the patients can be treated relatively conservatively with surgical excision and subsequent field-limited rad iation therapy only, with 77%;, survival at 5 years, None of the cases reviewed in this study was a branchiogenic carcinoma. (C) 1998 Americ an Cancer Society.