Gestational trophoblastic tumors metastatic to the lung. Radiologic--clinical correlations.

The relationship between human chorionic gonadotropin (HCG) titers in urine and the number of discrete metastatic pulmonary nodules was studied in patients with persistent trophoblastic disease, after evacuation of hydatidiform mole, and before starting chemotherapy. A significant difference in HCG titers was found between patients with 0 to 2 nodules and patients with 5 or more nodules. A weak linear relationship was found. The distribution of 57 discrete pulmonary nodules in 13 patients was plotted by lung zones (upper, middle, and lower thirds). Twenty-eight percent of the nodules were in the upper third of the lungs. Two patients had solitary apical nodules. This differs from the characteristic predominantly basilar distribution of blood-borne metastases of other neoplasms. Pulmonary spread may have occurred during curettage of moles, when the patients were recumbent and pulmonary blood flow was redistributed to the upper portions of the lungs.