Despite never smoking and experiencing no respiratory issues, a 70-year-old woman underwent a CT scan that revealed a 3-centimeter mass at the base of her left lung. Given her family history, including a sibling with lung cancer and other cancers, this discovery sparked significant concern. However, the mass was not cancerous.
Imaging Identifies Unique Blood Flow
Advanced imaging techniques showed that the triangular mass received its blood supply from an artery directly connected to the aorta, a key indicator of pulmonary sequestration. This rare congenital condition involves lung tissue developing without a normal airway connection, instead drawing blood from the body’s main circulation rather than the pulmonary arteries. Saran Lal Ajai Mokan Dasan, Aura P. Flores, and Khaja Misbahuddin of BronxCare Health System in New York City detailed this case on April 16, 2026, in the Journal of Cardiothoracic Surgery.
The woman had pre-existing conditions such as high blood pressure, prediabetes, and thyroid nodules. Her family history included lung cancer in a sibling, liver cancer in her mother, and lymphoma in her daughter. She reported no symptoms like cough, shortness of breath, recurrent infections, fever, or weight loss, and her physical examination was normal. A January 2023 CT scan identified a triangular mass measuring approximately 2.7 by 3.2 by 3.6 centimeters in the inner part of her left lower lung lobe, adjacent to the descending aorta.
A March 2023 PET scan played a key role in the diagnostic process. The mass did not absorb the radioactive sugar tracer typical of many cancers, showing only minimal activity at its edges, likely due to nearby collapsed lung tissue. This pattern suggested sequestration or a bronchogenic cyst rather than a tumor. In October 2024, CT angiography, which uses contrast dye to visualize blood vessels, confirmed the diagnosis by revealing an artery originating from the descending aorta.
A Rare Condition Diagnosed Later in Life
Pulmonary sequestration represents 0.15% to 6.4% of all congenital lung abnormalities, according to StatPearls, a clinical resource hosted by the National Library of Medicine. The BronxCare authors noted that diagnosis typically occurs between ages 35 and 45. In the adult cases they referenced, the intralobar type, which occurs within a normal lobe and matches this woman’s lesion, accounted for about 91% of cases. The abnormal artery originated from the thoracic aorta in approximately 87% of these cases. Many adults with this condition are asymptomatic. A Mayo Clinic review of 32 adults diagnosed between 1997 and 2016 found that 47% had no relevant symptoms, with a median diagnosis age of 42. Symptomatic patients most commonly experience cough or repeated lung infections.
Although surgeons offered to remove the lesion, she declined. Instead, her pulmonologists monitored her every six months with imaging. A June 2025 CT scan showed the mass remained stable at 3.1 centimeters, with unchanged arterial supply and no new suspicious nodules. The authors reported three years of complication-free follow-up, though the scans detailed in the report spanned about two and a half years. Surgery was planned if she developed recurrent infections, coughed up blood, or showed concerning changes in the lesion’s size.
Imaging’s Role in Differentiating Sequestration from Cancer
The BronxCare team emphasized that combining PET scan results with CT angiography was essential in ruling out cancer. Unlike malignant tumors, which typically show high uptake of the radioactive tracer, this mass displayed only faint activity at its edges, consistent with non-cancerous tissue. CT angiography further clarified the lesion’s blood supply, confirming its origin from the descending aorta rather than the pulmonary artery. This distinction is key, as systemic arterial supply is a defining feature of sequestration and helps differentiate it from other lung masses, including benign cysts or tumors.
Surgery: When It’s Necessary and When It’s Not
While surgery remains the standard treatment for symptomatic patients or those with complications, this case demonstrates that not all sequestrations require removal. The Mayo Clinic review found that among 32 adults with intralobar sequestration, 14 were managed conservatively without surgery, and none experienced complications over a median follow-up of nearly two years. The decision to forgo surgery in this woman aligned with growing evidence that stable, asymptomatic lesions can be safely monitored.
