Objective: To define persistent trophoblastic disease as a clinical entity of gestational trophoblastic disease. To describe its classification, treatment and follow-up. Type of study: Retrospective analysis. Setting: Trophoblastic Disease Center (TDC) in the Czech Republic TDC-CZ, Institute for the Care of Mother and Child, Prague. Methods: This study analyzes data from the Trophoblastic Disease Center consisting of 396 choriocarcinomas, 512 proliferative moles, 798 complete hydatid moles, 1299 partial hydatid moles, and 2105 persistent trophoblastic invasions treated at the TDC up to the year 2007. The study includes also 2615 cases of trophoblastic disease which documented by gynecologists and pathologists of the Czech Republic and registered in the TDC-CZ. Results: Persistent trophoblastic disease was defined and described in detail as follows: 1. Differentiating autothonic hCG, produced by the gestational trophoblast, from so-called “phantom hCG,” hypophyseal hCG and hCG during PLL-Q and PLL-U syndrome. 2. Evaluating the level and length of persistence of hCG relevant for the diagnosis of persistent trophoblastic disease. 3. Identifying three types of persistent trophoblastic disease: A. Non-metastatic B. Metastatic low-risk C. Metastatic high-risk 4. Described treatment, indications, and choice of various chemotherapeutic protocols in individual types of persistent trophoblastic disease as well as its follow-up. Conclusion: This study enables the differentiation of persistent trophoblastic disease in general gynecologic and obstetric clinical practice, by evaluating the presence, level, and length of persistence of hCG, and thus allowing for timely referral of the patient to the Trophoblastic Disease Center in the Czech Republic.

        Key words: persistent trophoblastic disease, diagnosis, treatment, classification, follow-up