Differential Diagnosis for Scattered Centrolobular Nodularity on Chest CT
Single Most Likely Diagnosis
- Infectious Bronchiolitis: This is the most likely diagnosis given the description of scattered centrolobular nodularity, which is a common finding in infectious bronchiolitis, particularly when caused by viral or mycoplasma infections. The pattern is indicative of inflammation and infection in the small airways.
Other Likely Diagnoses
- Inflammatory Bronchiolitis: Conditions such as bronchiolitis obliterans or follicular bronchiolitis can present with similar imaging findings due to inflammation of the bronchioles.
- Hypersensitivity Pneumonitis: An allergic reaction to inhaled substances can cause an inflammatory response in the lungs, leading to centrolobular nodules on CT scans.
- Respiratory Bronchiolitis: Often associated with smoking or environmental exposures, this condition can cause similar radiographic findings due to the inflammatory response in the small airways.
Do Not Miss Diagnoses
- Miliary Tuberculosis: Although less common, miliary TB can present with a similar pattern of small nodules throughout the lungs and is critical to diagnose due to its severe implications and need for prompt treatment.
- Fungal Infections: Certain fungal infections, such as histoplasmosis or cryptococcosis, can cause a miliary pattern or scattered nodules on chest CT and are crucial to identify due to their potential severity, especially in immunocompromised patients.
- Metastatic Disease: While less likely to present with a pure centrolobular pattern, metastatic disease to the lungs can sometimes appear as numerous small nodules and is a critical diagnosis not to miss due to its significant implications for patient management and prognosis.
Rare Diagnoses
- Lymphoid Interstitial Pneumonia (LIP): A rare condition characterized by infiltration of the lung interstitium by lymphoid cells, which can present with a variety of radiographic patterns, including nodules.
- Pulmonary Langerhans Cell Histiocytosis: A rare disorder that can cause nodular lesions on chest CT due to the proliferation of Langerhans cells in the lung.
- Pulmonary Sarcoidosis: While more commonly associated with hilar lymphadenopathy and parenchymal granulomas, sarcoidosis can rarely present with a nodular pattern on CT scans, including a centrolobular distribution.