A61-06 Refractory Malignant Pleural Effusion Despite Pleurodesis in a Teenager With LI-Fraumeni Syndrome and Mediastinal Myxoid Pleomorphic Liposarcoma

Abstract Recurrent malignant pleural effusion despite pleurodesis is a complex and difficult clinical concern, especially in pediatric populations. This patient, a 16-year-old transgender (biologic female) with Li-Fraumeni Syndrome (due to a p53 mutation causing a missense variant) who presented with a mediastinal mass. A biopsy was completed, and they were found to have a myxoid pleomorphic liposarcoma of the anterior mediastinum. They underwent resection via thoracotomy that was complicated by preoperative rupture and liquid tumor spillage into the thoracic cavity. Final pathology aligned with the biopsy diagnosis with clinical stage T2, N0, M0 and suspected clinical contamination of the pleural spaces. They had baseline spirometry, lung volumes, and diffusion capacity testing, which were notable for mild obstructive pulmonary disease with significant bronchodilator administration, normal lung volumes, and normal diffusion capacity (FVC 94% predicted, FEV1 78% predicted, FEV1/FVC 82% predicted). The patient underwent intensity-modulated radiation therapy for approximately 6 weeks. They were also treated with chemotherapy via Children’s Oncology Group protocol ARST 1321. Six months after diagnosis, a left-sided chest mass was noted when admitted for scheduled chemotherapy. They returned and underwent an excision of the mass, left video-assisted thoracic surgery (VATS), partial parietal pleurectomy and resection of pleural masses and left lower lobe wedge resection. Approximately one month later, they followed up in Pulmonology clinic and were noted to have a persistent left-sided pleural effusion with spirometry notable for a moderate mixed obstructive and restrictive pattern (FVC 59% predicted, FEV1 52% predicted, and FEV1/FVC 87% predicted). They underwent drainage of the pleural fluid and talc pleurodesis. Pathological evaluation of the pleural fluid showed cells consistent with liposarcoma. One month later, they were noted to have a reaccumulation of the left sided pleural effusion with worsening obstructive and restrictive disease (FVC 56% predicted, FEV1 48% predicted, FEV1/FVC 86% predicted). Given the persistence of the effusion and the lack of respiratory symptoms, the decision was made to monitor outpatient and continue chemotherapy and radiation therapy to treat the underlying cause of the effusion. This case highlights multiple difficult and complex points, notably the lack of data for refractory malignant pleural effusions in pediatric patients, especially those with known liquid tumor thoracic cavity spillage. It also highlights the complexity of spirometry interpretation and clinical management in this individual who has active chemotherapy, radiation therapy, persistent pleural effusion, history of a pulmonary wedge resection, and likely diaphragmatic weakness from multiple surgeries. This abstract is funded by: None