Metastatic clear cell renal cell carcinoma:a clinicopathological analysis

Objective To describe the pathological features of the metastatic clear cell renal cell carcinomas (RCCs) to the lung, adrenal gland as well as thyroid gland, and to explore the diagnosis and differential diagnoses of metastatic clear cell RCCs. Methods 7 cases of metastatic clear cell RCCs and their 5 cases of primary tumors were studied by hematoxylin and eosin stain and immunohistochemical techniques. Results The predominant histologic pattern of metastatic clear cell RCCs was characterized by the presence of small nest, alveolar, acinar and glandular structures of neoplastic cells separated by a prominent vascular stroma. They might share morphologic similarities with some primary pulmonary adenocarcinoma, adrenalcortical tumors and thyroid clear cell carcinoma. All seven cases of metastatic clear cell RCCs and 5 cases of primary clear cell RCCs showed positive CD10 membranous staining. Conclusion CD10 is a superior marker for distinguishing metastatic clear cell RCCs from the primary carcinoma of lung, adrenal and thyroid gland.