Image Cytometry DNA-Analysis of Fine Needle Aspiration Cytology to Aid Cytomorphology in the Distinction of Branchial Cleft Cyst from Cystic Metastasis of Squamous Cell Carcinoma: A Prospective Study

Objective: Frequently, the distinction between branchial cleft cyst and cystic metastases from squamous cell carcinoma is difficult by cytomorphology. In a prospective study, we investigated the need for, and the value of, image cytometry DNA‐analysis as a complement to cytologic evaluation of cystic lesions in the neck. Study Design: Image cytometry DNA‐analysis was performed on the fine needle aspiration cytology smears from 50 patients, referred to our department, with a solitary cystic lesion in the lateral region of the neck. Methods: Smears from aspirates were Giemsa stained and cytologically evaluated. Ahrens image analysis was used for DNA analysis on smears stained with Schiff reagent, and lymphocytes were used as control cells. Epithelial cells with DNA values exceeding 5c were regarded as aneuploid, indicating malignancy. Results: Nine lesions were diagnosed as squamous cell cancer metastases cytologically. DNA analysis showed aneuploidy in all of them except one. Three of these lesions had earlier been diagnosed as branchial cleft cyst at the referring hospital. Eight lesions were cytologically inconclusive and four of them were revealed as cystic metastasis at histopathologic analysis, and DNA analysis showed aneuploidy in all but one, which could not be analyzed. Two of these lesions were also diagnosed as branchial cleft cysts at the referring hospital. All benign lesions were diploid. Nine lesions were thyroid and salivary gland lesions. Conclusion: Image cytometry DNA‐analysis was shown to help in the distinction between benign and malignant cystic lesions. Thus, when conventional cytomorphology does not suffice, DNA‐analysis is clearly a valuable supplement.