Abstract
BACKGROUND: Primary choriocarcinoma of the pulmonary artery is an exceedingly rare malignant neoplasm, which is often misdiagnosed due to its nonspecific clinical presentation. While this condition is characterized by the presence of trophoblastic cells, typically associated with gestational trophoblastic diseases, we encountered a case occurring in an extragenital location. The rarity of such tumors makes it challenging for clinicians to consider them in differential diagnosis, especially when the initial symptoms mimic more common conditions such as pulmonary thromboembolism (PTE). CASE DESCRIPTION: We present a clinical case of a 32-year-old female with suspected PTE, attributed to severe cough, hemoptysis, chest pain, oral contraceptive use, and a pulmonary artery filling defect observed on computed tomography pulmonary angiography (CTPA). The patient was treated with standard anticoagulation therapy; however, there was no improvement in the clinical condition. A biopsy was subsequently performed, leading to the histopathologic diagnosis of primary pulmonary artery choriocarcinoma with the presence of malignant trophoblastic cells within the pulmonary artery. The patient underwent chemotherapy and achieved complete remission within a 1-year follow-up period, as confirmed by β-human chorionic gonadotropin (β-HCG) tests and imaging examinations showing marked improvement. CONCLUSIONS: This case underscores the importance of early recognition and accurate diagnosis of primary pulmonary artery choriocarcinoma, a condition that can be easily overlooked due to its rarity and deceptive clinical presentation. Timely diagnosis is crucial for the initiation of appropriate treatment, such as chemotherapy, which in this instance, contributed to the patient's survival. This report highlights the need for heightened clinical suspicion and the use of invasive diagnostic procedures in cases where the clinical picture is atypical and does not respond to standard therapeutic interventions.