INTRODUCTION:Methotrexate is an analogue of folic acid that inhibits cellular proliferation by inducing an intracellular deficiency of folate coenzymes. Lung toxicity, while rare, often occurs after weeks to months of low dose oral methotrexate therapy.CASE PRESENTATION: A 46 year old male with a history of T cell lymphoma status post chemotherapy on POMP maintenance therapy and pleurX catheter for malignant pleural effusion presented to the ED with fever for 4 days. Associated symptoms were dry cough, chills, and fatigue. He denied drug allergies.BP 153/84, HR 135, SpO2 98% on room air, and temperature 101.5F. WBC was 3.2 and COVID PCR was negative. Broad spectrum antibiotics were initiated. CT thorax showed upper lobe predominant ground-glass opacities suggestive of a multifocal pneumonia or drug reaction. He became hypoxic requiring 3L of oxygen and underwent bronchoscopy. Transbronchial biopsy revealed lung parenchyma with isolated giant cells and loosely formed granulomas consistent with hypersensitivity pneumonia. Left upper lobe broncho-alveolar lavage had lymphocytic predominance and elevated CD4:CD8 ratio (4.7), all supporting the diagnosis of methotrexate pneumonitis. Empiric treatment for PJP and Prednisone were started. Viral, bacterial, fungal studies and PJP stain were negative. Antibiotics were stopped and steroids were continued for 2 weeks. His symptoms improved and fevers subsided. As an outpatient, repeat CT thorax and PFTs were ordered and he continues to improve clinically.

Background: Pulmonary artery intimal sarcoma (PAIS) is a rare malignancy of vasculature that carries a very poor prognosis that is often misdiagnosed as a pulmonary embolism due to overlapping clinical and radiological features. It is a very aggressive malignancy with surgery the mainstay of initial management. Chemotherapy is normally given postoperatively, although it is not clear if chemo and radiotherapy bring any improvement, some data report an increase in survival in patients who received multimodality therapy vs single therapy. Case: A 48 year-old female was initially diagnosed with a pulmonary embolism based on clinical presentation and imaging. She was treated vigorously but continued to show no improvement after two weeks. She underwent an open thrombectomy and a large concurrent pulmonary artery intimal sarcoma (PAIS) was found. The mass was adherent to the intima and extended into the left and right pulmonary arteries. The tumor was not fully resected and tissue results showed poorly differentiated sarcoma. A treatment plan was then initiated to include systemic chemotherapy. She developed metastatic disease despite receiving multimodal therapy and died with within 2 years from the initial diagnosis. Conclusion: Persistent symptoms in patients diagnosed and treated adequately for pulmonary artery thrombosis should indicate a possible comorbid condition including sarcoma. This is particularly the case in the older age group with imaging that suggests central embolism despite treatment.