CARCINOEMBRYONIC ANTIGEN-ASSAY OF INTRAABDOMINAL FINE-NEEDLE ASPIRATES

Differentiating abscesses from necrotic tumors- has important therapeu tic implications. Currently, cytologic examination is the ''gold stand ard,'' but it has a low sensitivity for cystic/necrotic tumors. To add ress this problem, a prospective study was conducted comparing the res ults of cytologic examination with those of carcinoembryonic antigen ( CEA) immunoassay of fine-needle aspirates in 24 patients undergoing ra diologically or surgically guided fine-needle aspiration. Of 26 fine-n eedle aspirates, 20 were malignant and 6 benign. Final results were co rrelated with pathologic examination (when available), clinical review , and follow-up. Three patients had an abscess associated with perfora ted, recurrent carcinoma, of whom only one had cytologic assessment pr ior to drainage. The sensitivity of fine-needle aspiration was 85%, an d for adenocarcinoma alone, 80%. CEA sensitivity (greater than 5 ng/mL ) was 50%, and for adenocarcinoma, 90%; the specificity of the assay w as 64%. A high CEA level alone was diagnostic of metastatic carcinoma of the colon in two fine-needle aspirates. Cytologic assessment and CE A assay of fine-needle aspirates and cyst/abscess drainage facilitate the diagnosis of unsuspected adenocarcinoma.