Differential Diagnosis for 3mm Nodules in Lung, Multiple
Single Most Likely Diagnosis
- Metastatic disease: Given the small size and multiplicity of the nodules, metastatic disease from a primary cancer (e.g., breast, colon, or melanoma) is a leading consideration, as it often presents with numerous small nodules throughout the lungs.
Other Likely Diagnoses
- Miliary tuberculosis: This condition, characterized by a widespread dissemination of tuberculosis in the lungs, can present with numerous small nodules, typically 2-3 mm in size, and is a common cause of this radiographic pattern, especially in endemic areas or immunocompromised patients.
- Histoplasmosis: A fungal infection that can cause small, diffuse nodules in the lungs, particularly in individuals who have been exposed to the fungus, often through outdoor activities in endemic regions.
- Sarcoidosis: An autoimmune disease that can manifest with numerous small nodules in the lungs due to granulomatous inflammation, although these are often accompanied by lymphadenopathy and other systemic symptoms.
Do Not Miss Diagnoses
- Pulmonary lymphangitic carcinomatosis: Although less common, this condition involves the spread of cancer to the lymphatic vessels of the lungs and can present with small nodules. It is critical to identify due to its poor prognosis and the need for specific treatment.
- Pulmonary veno-occlusive disease: A rare condition that can mimic other diseases with small lung nodules but requires specific diagnosis due to its implications for treatment and prognosis.
Rare Diagnoses
- Langerhans cell histiocytosis: A rare disorder that can cause small lung nodules, typically in smokers, due to the proliferation of Langerhans cells.
- Silicosis or coal workers' pneumoconiosis: Occupational lung diseases that can result in small nodular patterns on imaging, particularly in individuals with a history of exposure to silica or coal dust.
- Wegener's granulomatosis (Granulomatosis with Polyangiitis): A form of vasculitis that can affect the lungs and present with nodules, although it is often accompanied by other systemic symptoms and findings.