Management of Mediastinal and Hilar Lymphadenopathy on Chest X-ray
Obtain a high-resolution CT scan of the chest as the immediate next step to better characterize the lymphadenopathy, assess for additional abnormalities, and guide further diagnostic workup 1, 2.
Initial Imaging Workup
High-resolution CT (HRCT) is essential to evaluate lymph node size, distribution pattern (unilateral vs. bilateral, symmetric vs. asymmetric), presence of parenchymal abnormalities, and to distinguish nodes from vascular structures 1, 2, 3.
CT with IV contrast is preferred when feasible, as it improves detection of mediastinal and hilar adenopathy by distinguishing nodes from mediastinal vessels 4.
Document specific features on CT: measure short-axis diameter of nodes (>1 cm is considered enlarged), assess for coalescence, central necrosis, and invasion of surrounding fat 4, 3.
Clinical Assessment During Initial Evaluation
Focus your history and physical examination on these specific findings:
Symptoms suggesting sarcoidosis: erythema nodosum, fever, and arthralgia (Löfgren's syndrome), lupus pernio, or Heerfordt's syndrome 1, 2.
Constitutional symptoms: fever, weight loss, night sweats suggesting lymphoma or tuberculosis 1.
Occupational exposures: silica exposure (silicosis), bird or mold exposure (hypersensitivity pneumonitis) 2, 3.
Medication history: drug-induced lymphadenopathy 3.
Diagnostic Algorithm Based on CT Pattern
Bilateral Symmetric Hilar Lymphadenopathy
High suspicion for sarcoidosis, particularly in young adults with multiple symmetric enlarged nodes 1, 3.
Lymph node sampling is NOT recommended if classic presentation of Löfgren's syndrome, lupus pernio, or Heerfordt's syndrome is present 1.
Close clinical follow-up is required if biopsy is deferred 1, 2.
Note: The American Thoracic Society makes no firm recommendation for or against lymph node sampling in asymptomatic bilateral hilar lymphadenopathy, but sarcoidosis is confirmed in 85% of suspected stage 1 disease, with alternative diagnoses including tuberculosis (38%) and lymphoma (25%) 1.
Unilateral or Asymmetric Lymphadenopathy
Tissue diagnosis is mandatory due to higher likelihood of malignancy (lung cancer, lymphoma, metastatic disease) 4, 5.
Proceed directly to tissue sampling using the algorithm below 4, 1.
Lymphadenopathy with Parenchymal Abnormalities
Multidisciplinary discussion is recommended before proceeding to invasive procedures 2.
Consider broader differential: tuberculosis, fungal infections (histoplasmosis, coccidioidomycosis), lymphangitic carcinomatosis, or interstitial lung disease 3, 5.
Laboratory Testing
Obtain these tests based on clinical suspicion:
Pulmonary function tests (spirometry and diffusion capacity) to assess for restrictive physiology and impaired gas exchange 1, 2.
Tuberculosis testing: interferon-gamma release assay (IGRA) or tuberculin skin test 1, 2.
Serum angiotensin-converting enzyme (ACE) if sarcoidosis is suspected 1, 2.
Tissue Sampling Strategy When Indicated
For patients with abnormal mediastinal and/or hilar lymph nodes on CT and/or PET imaging, endosonography (EBUS and/or EUS) is recommended over surgical staging 4.
First-Line Approach
EBUS-guided transbronchial needle aspiration (EBUS-TBNA) is the preferred first technique with diagnostic yield of 87% and minimal complications (<0.1%) 4, 1, 2, 5.
Core needle biopsy is preferred over fine-needle aspiration to enable histological examination and architectural assessment 1, 2.
Second-Line Approach
Mediastinoscopy should be performed if EBUS/EUS does not reveal nodal involvement in situations of high clinical suspicion, as it has the highest negative predictive value (98% diagnostic yield) to rule out mediastinal lymph node disease 4, 1, 2.
Surgical lung biopsy may be considered when all available clinical, laboratory, radiologic, and bronchoscopic results do not yield a confident diagnosis 2.
Follow-up Recommendations
Close clinical follow-up is essential for patients with asymptomatic bilateral hilar lymphadenopathy where sampling is deferred 1, 2.
Follow-up imaging at appropriate intervals (typically 3-6 months initially) based on suspected diagnosis and clinical course 1, 2.
Repeat pulmonary function tests regularly if interstitial lung disease is suspected 1, 2.
Common Pitfalls to Avoid
Do not assume bilateral hilar lymphadenopathy is always benign: while sarcoidosis is most common, lymphoma and tuberculosis remain important differential diagnoses requiring tissue confirmation in many cases 1, 5.
Do not rely on chest X-ray alone: mediastinal widening may be subtle and careful CT review is necessary, as initial chest radiographs were misinterpreted as normal in some cases of serious disease 4.
Do not skip tissue diagnosis in asymmetric or unilateral disease: these patterns have higher malignancy risk and require pathologic confirmation 4, 5.
Do not order PET scan before CT: CT should be obtained first to characterize anatomy; PET has high false-positive rates in inflammatory conditions like sarcoidosis 6.