The natural history of theca lutein cysts.

The histories of 386 patients with untreated hydatidiform mole were reviewed to define the clinical aspects of accompanying theca lutein cysts. These cysts occurred in 102 patients (26.4%), with three patients experiencing cyst-related complications. Mean cyst size at diagnosis was 7.3 cm (3-20 cm), and did not correlate with post-molar trophoblastic disease development. Bilateralism occurred more often in patients developing post-molar trophoblastic disease. In patients with post-molar trophoblastic disease, 83% (45 of 54) experienced theca lutein cyst regression and 16.7% an increase in cyst size with falling beta-hCG titers. Post-molar trophoblastic disease developed in 44 patients. Theca lutein cyst growth occurred in 31.8% of the patients with beta-hCG plateau/rise and in 4.5% with falling titers. Disappearance of theca lutein cysts before diagnosis of post-molar trophoblastic disease occurred in 31.8%. Theca lutein cysts persisted in three patients for long periods (15-18 weeks) after beta-hCG regression. We conclude that theca lutein cysts commonly accompany hydatidiform mole and are associated with an increased risk of post-molar trophoblastic disease, a risk that is higher with cyst bilateralism or severe complications of hydatidiform mole. Theca lutein cysts uncommonly have serious complications; their clinical behavior does not depend entirely on changes in beta-hCG levels, as cysts may persist for long periods after beta-hCG regression.