lewis-x-antigen and Mediastinal-Cyst

A 24-year-old man was admitted to our hospital in June 1996 with complaints of anterior chest discomfort. Chest X-ray films on admission showed an abnormal mediastinal shadow with well-defined margin. Chest X-ray examinations about 6 weeks earlier had not detected any abnormalities. Laboratory tests on admission showed a high serum concentration of Siaryl Lewis X-i antigen (SLX). A computed tomographic scan of the chest showed a large (6 x 6 x 12 cm) homogeneous mass in the right anterior mediastinum. The mass was removed completely and histologically diagnosed as a thymic cyst. Biochemical analysis of fluid from the cyst revealed remarkably high levels of SLX, CA 19-9, and CEA. In immunohistochemical studies, epithelial cells from the cystic walls stained positive for SLX, CA 19-9, and CEA. After the operation, the level of serum SLX returned almost to normal.

Topics: Adult; Biomarkers, Tumor; Carcinoembryonic Antigen; Humans; Lewis X Antigen; Male; Mediastinal Cyst

A 66-year-old woman, who had complained of left ptosis and been diagnosed as having myasthenia gravis (ocular type) 9 years previously, was admitted to our hospital for further examination of an abnormal mass shadow on chest X-ray film. Chest computerized tomography (CT) revealed a cystic tumor in the anterior mediastinum and thoracotomy was performed to make a definitive diagnosis. The tumor could be removed completely and was diagnosed histologically as a thymic cyst with thymoma. The cyst was 32 x 30 x 28 mm in size and contained about 10 ml of brown turbid fluid. The levels of CEA (61.3 ng/ml), SLX (24,000 U/ml) and CA125 (1300 U/ml) were markedly increased in the cystic fluid, while those in serum were not elevated. Immunohistochemical staining demonstrated the epithelial cells lining the cyst to contain SLX. The findings suggest that SLX was produced in the epithelial cells of the cyst. However, neither CEA nor CA125 was positive in the epithelial cells. From our review of reported cases of thymic cyst showing elevated levels of tumor markers in the cystic fluid, the main mechanism of marked elevation of tumor markers seems to be condensation in the cystic fluid rather than increased production in epithelial cells lining the cyst. Cases of thymic cyst with thymoma are extremely rare, but our case was concluded to be incidentally associated with non-invasive thymoma.

Topics: Aged; Antigens, Tumor-Associated, Carbohydrate; Biomarkers, Tumor; Carcinoembryonic Antigen; Female; Humans; Lewis X Antigen; Mediastinal Cyst; Thymoma; Thymus Neoplasms

A 56-year-old man, tentatively diagnosed as having cardiomegaly, was found to have a large cyst in the left anterior mediastinum. At thoracotomy a multilocular cystic mass containing a colorless serous fluid was found and resected. Histologically, the cyst was lined with flattened epithelial cells, and thymic tissue was present in the cyst's wall; a diagnosis of thymic cyst was made. There were no malignant components or inflammatory changes. Sialylated Lewis X-i (SLX), carbohydrate antigen 19-9 (CA19-9) and tissue polypeptide antigen (TPA) in the cystic fluid were markedly elevated, while the serum concentrations of these tumor markers were within the normal ranges. Immunohistochemical studies showed the epithelial cells lining the cyst to contain CA19-9 and SLX. The findings suggest the tumor markers to have originated in the thymic epithelium lining the cyst.

Topics: Antigens, Tumor-Associated, Carbohydrate; Biomarkers, Tumor; Humans; Immunohistochemistry; Lewis X Antigen; Male; Mediastinal Cyst; Middle Aged; Peptides; Radiography; Tissue Polypeptide Antigen