Metastatic squamous carcinoma presenting as a neck cyst. Differential diagnosis from inflamed branchial cleft cyst in fine needle aspirates.

Fine needle aspirates (FNAs) from five cases of cystic squamous carcinoma metastatic to cervical lymph nodes were compared to those of five cases of branchial cleft cyst to determine whether these lesions could be differentiated by cytologic examination. Squamous carcinoma could be recognized by the following cytologic features: increased nuclear/cytoplasmic ratio, irregularity of nuclear outline and nuclear hyperchromatism. The branchial cleft cysts showed essentially benign squamous cells with only mild nuclear atypia. The background of the malignant aspirates showed more necrotic debris but fewer polymorphonuclear cells than that of the branchial cleft cysts. By adhering to these cytologic criteria a definitive diagnosis is possible; it should be confirmed by histologic examination.