Differential Diagnosis for Lung Mass and Leukocytosis
Single Most Likely Diagnosis
- Lung Cancer with Secondary Infection or Tumor-Related Leukocytosis: This is often the first consideration due to the high prevalence of lung cancer and its potential to cause both a lung mass and systemic symptoms like leukocytosis, either through direct tumor effects or secondary infections.
Other Likely Diagnoses
- Pneumonia: Certain types of pneumonia, especially those caused by bacteria like Streptococcus pneumoniae or Staphylococcus aureus, can present with a lung mass (due to consolidation) and significant leukocytosis.
- Abscess or Empyema: A lung abscess or empyema can cause a mass-like appearance on imaging and is associated with significant leukocytosis due to the infectious process.
- Tuberculosis: While less common in some regions, tuberculosis can cause a lung mass and systemic symptoms including leukocytosis, especially in immunocompromised patients.
Do Not Miss Diagnoses
- Sepsis from Any Cause: Sepsis can cause leukocytosis and, if originating from a lung source (like pneumonia), could also explain a lung mass. Missing sepsis can be fatal.
- Pulmonary Embolism with Infarction: While not typically causing leukocytosis directly, a large pulmonary embolism can lead to infarction, which might appear as a mass on imaging, and could be associated with a secondary infectious process or systemic inflammatory response.
- Fungal Infections (e.g., Aspergillosis, Histoplasmosis): In immunocompromised patients, fungal infections can cause lung masses and significant systemic illness, including leukocytosis.
Rare Diagnoses
- Echinococcosis (Hydatid Disease): This parasitic infection can cause cystic lung masses and, if complicated by rupture or secondary infection, could lead to leukocytosis.
- Diaphragmatic Hernia with Lung Compression: Though not directly causing leukocytosis, a diaphragmatic hernia can cause lung compression that might appear as a mass, and if complicated by infection or ischemia, could lead to systemic symptoms.
- Lymphoma: Both Hodgkin and non-Hodgkin lymphoma can involve the lung and cause masses, and systemic symptoms including leukocytosis, especially if there is significant disease burden or transformation.