Onkaramurthy, Neema Jayachamarajapura

Abstract Introduction Mediastinal masses encompass broad differentials of reactive, inflammatory, infectious or neoplastic etiology. In the background of extra thoracic malignancy, it raises a high suspicion for primary cancer or metastatic lymphadenopathy. However, a benign anatomical variant can mimic these findings and lead to unnecessary diagnostic procedures and patient anxiety. Recognizing mimickers becomes crucial in avoiding misdiagnosis and overtreatment. Case A 50-year-old woman with no significant past medical history presented with a two-day history of headache, associated with cough, orthopnea and lower extremity edema. Vital signs were significant for elevated blood pressure at 199/107 mm Hg. Laboratory findings noted a markedly elevated B-type natriuretic peptide (19,000 pg/mL), increased serum creatinine (1.4 mg/dL from baseline 0.7 mg/dL) and proteinuria. Chest X-ray revealed pulmonary vascular congestion. Autoimmune serologies were positive for antinuclear antibody (titer 1:2560), ribonucleoprotein antibody, and RNA polymerase III antibody. Renal biopsy confirmed scleroderma renal crisis. She was treated for hypertensive emergency secondary to scleroderma renal crisis. Further evaluation for elevated total protein revealed monoclonal gammopathy on electrophoresis and 30% plasma cells on bone marrow biopsy, consistent with smoldering multiple myeloma. A chest computed tomography scan incidentally identified a 4 × 3 cm lobular right paratracheal mass. Tissue biopsy was requested to exclude plasmacytoma. Bronchoscopy with endobronchial ultrasound revealed a large hypoechoic paratracheal lesion. Biopsy was aborted due to its cystic appearance and risk of airway flooding. Subsequent magnetic resonance imaging was obtained for tissue characterization which delineated the mass as a thin walled, fluid filled structure communicating with the superior aortic recess, consistent with a high riding superior pericardial recess which is a benign anatomical variant. She was discharged with plans for outpatient multidisciplinary follow up, including pulmonary evaluation for interstitial lung disease surveillance. Discussion High riding pericardial recess is a benign anatomical variant which can closely mimic pathologic masses or lymphadenopathy on cross sectional imaging. Key is identification of probable communication with the superior aortic recess associated with fluid attenuation. Knowledge of anatomy, comprehensive multimodal imaging review, and multidisciplinary discussion are key to prevent unnecessary investigation of mediastinal abnormalities. This abstract is funded by: None

Abstract Introduction: Prolonged mechanical ventilation can often be complicated with post-intubation tracheal stenosis (PITS). It usually manifests within few weeks following extubation. However, delayed presentations are rare and have disastrous outcomes if not identified. Early recognition of stridor and dyspnea post-extubation is crucial for timely intervention. We report a case of late presentation of PITS in a 67-year-old female patient with new-onset stridor after prolonged intubation. Case: A 67-year-old female with past medical history of coronary artery disease, type 1 diabetes, obstructive sleep apnea presented with a six-week history of progressive dyspnea on exertion and stridor. This occurred in the context of a three-week intubation following a pulseless electrical activity (PEA) arrest over five months prior. Immediately post-extubation, the patient had developed stridor without hypoxia or exertional symptoms and was subsequently discharged home without further investigation. On this presentation, she was afebrile and saturating 95% on room air with audible inspiratory stridor at bedside. Respiratory viral panel and autoimmune work up was negative. Computed tomography (CT) scan noted a significant circumferential narrowing in the proximal portion of the trachea measuring 2.5 cm in length with 0.5 cm in width with associated wall thickening. She was managed with 2.25% racemic epinephrine as needed and prednisone 10 mg daily with rescue continuous positive airway pressure (CPAP) until intervention could be safely performed after clopidogrel washout. On Day 5, she underwent rigid bronchoscopy with extensive CO2 laser vaporization (Fig. B) of scar release and paclitaxel-coated balloon dilation of the 3 mm narrowing (Fig. A) to 12 mm (Fig. C). Her stridor resolved with significant improvement in dyspnea and exercise tolerance. She was subsequently discharged on a steroid taper with outpatient interventional pulmonology follow up for repeat rigid bronchoscopy in 4 weeks to evaluate for restenosis. Discussion: Tracheostomy is often considered when extended period of intubation is anticipated as it can lead to increased risk of complications like PITS. It is important to have a high index of suspicion for tracheal stenosis in patients with a history of prolonged mechanical ventilation presenting with new-onset stridor, even when the symptoms are mild or intermittent. Early recognition and timely intervention can prevent the progression of stenosis and improve morbidity and clinical outcomes. Additionally, these patients tend to have an increased incidence of recurrence which requires close follow up for restenosis.