Abstract
BACKGROUND: Circulating tumor cells (CTCs) are tumor cells that have shed from a primary tumor and circulate in the peripheral blood. Recent experimental and clinical studies show that CTCs can be detected in early-stage disease. CASE PRESENTATION: We report three cases of pituitary adenoma (PA) in which tumor cells with particles were detected in the interstitial vascular compartment by transmission electron microscopy. Tumors were completely resected. Immunohistochemical analysis showed a β-catenin score of 10.5 ± 1.5 in the three cases with CTCs compared with 2.4 ± 0.5 in 24 control adenomas. The Ki-67 labeling index was 2.1 ± 0.7 in CTCs vs. 0.2 ± 0.3 in control cases (p = 0.043), and the p53 score was 4.33 ± 1.3 vs. 0.31 ± 0.17 (p = 0.000). The E-cadherin score did not differ significantly between the two groups. CONCLUSIONS: CTCs can be detected in benign tumors such as PAs and not only in late-stage malignant tumors with apparent distant metastases. The present findings suggest that pituitary carcinomas develop from adenomas.