PRIMARY MEDIASTINAL CHORIOCARCINOMA (PMC) IN A YOUNG WOMAN WITH HEMOPTYSIS AND A LUNG MASS

Abstract

SESSION TITLE: Medical Student/Resident Lung Cancer Posters SESSION TYPE: Med Student/Res Case Rep Postr PRESENTED ON: October 18-21, 2020 INTRODUCTION: Primary mediastinal choriocarcinoma (PMC) is an extra gonadal, non-gestational, angioinvasive rare germ cell neoplasm that mostly arises along the midline structures. PMC contains syncytiotrophoblastic cells which secrete human chorionic gonadotropin hormone (hCG). An elevated hCG is considered an important serologic tumor marker in the diagnosis of mediastinal germ cell tumor, in the absence of gestation and with no previous gynecologic malignancy. CASE PRESENTATION: A 39 year-old woman with no past medical history was admitted to the hospital with severe right sided chest pain associated with hemoptysis that started 2 weeks prior to admission. Physical exam revealed decreased breath sounds on the right hemithorax with dullness to percussion. Bloodwork was significant for β-HCG of 6,566 mlU/ml with negative alpha fetoprotein, and normal lactate dehydrogenase. A CT scan of the chest revealed a large necrotic solid mass with numerus enlarged vessels located in the anterior mediastinum (Figure 1). PET scan was negative for any metastatic lesions. Transvaginal ultrasound was negative for intrauterine or ectopic pregnancy. Transthoracic core biopsy showed poorly differentiated choriocarcinoma. Immunohistochemistry staining was positive for β-HCG, placental alkaline phosphatase, and pancytokeratin AE1/AE3 (Figure 2). The tumor was not amenable to surgical resection due to its large size and high vascularity. The patient was started on cisplatin and etoposide followed by etoposide, MTX, Act-D, cyclophosphamide, and vincristine (EMA-CO). After the first course of chemotherapy, the levels of β-HCG markedly decreased. DISCUSSION: PMC is a rare malignancy in both genders, more prevalent in men than in women. The natural process of PMC has been poorly understood. Possible theories include: (1) trophoblastic embolus related to a gestational event after a long period of latency; (2) metastases from a primary gonadal choriocarcinoma; (3) retained primordial germ cells that migrated during embryogenesis. An extensive workup is required to exclude other β-HCG-positive tumors from PMC, such as primary poorly differentiated non-small cell carcinoma of the lung, and gestational metastatic choriocarcinoma. Our patient was found to have a large highly vascular mass in the presence of elevated β-HCG, and absence of primary genital tumor. The histological features showed extensive areas of hemorrhage and necrosis and biphasic cellular population including cytotrophoblastic and syncytiotrophoblastic cells. In contrast to gestational choriocarcinoma, PMC is rapidly progressive and fatal in the great majority of cases with a dismal 5 years survival of less than 5%. CONCLUSIONS: Due to the rarity of PMC, currently there is no consensus regarding treatment guidelines. Thus, case reports such as this contribute to the scant literature to raise the profile of this rare and devastating disease. Reference #1: Ruan Z, Wang S, Wang Z, Jing Y. A rare case of bilateral massive hemothorax from spontaneous rupture of a primary mediastinal mixed germ cell tumor. Ann Thorac Surg. 2012;93:664–666 Reference #2: Bachmann J, Ernestus K, Werner T, et al. Detection of primary choriocarcinoma in the mediastinum by F-18 FDG positron emission tomography. Clin Nucl Med. 2007;32:663–665. Reference #3: Serno J, Zeppernick F, Jakel J, Primary pulmonary choriocarcinoma; cas report and the review of the literature, Gynecologic nad obstetric investigation, vol. 74, no. 2, pp. 171-176,2012 DISCLOSURES: No relevant relationships by Marwah Abduljabbar, source=Web Response No relevant relationships by Sara Mehrsefat, source=Web Response No relevant relationships by jorge otoya, source=Web Response No relevant relationships by Noman Subhani, source=Web Response no disclosure on file for Maria Wallis-Crespo