CT pattern of lymphadenopathy in untreated patients undergoing bronchoscopy for suspected sarcoidosis

Imaging of Pulmonary Sarcoidosis-A Review

Sarcoidosis is the classic multisystem granulomatous disease. First reported as a disorder of the skin, it is now clear that, in the overwhelming majority of patients with sarcoidosis, the lungs will bear the brunt of the disease. This review explores some of the key concepts in the imaging of pulmonary sarcoidosis: the wide array of typical (and some of the less common) findings on high-resolution computed tomography (HRCT) are reviewed and, with this, the concept of morphologic/HRCT phenotypes is discussed. The pathophysiologic insights provided by HRCT through studies where morphologic abnormalities and pulmonary function tests are compared are evaluated. Finally, this review outlines the important contribution of HRCT to disease monitoring and prognostication.

EBUS versus EUS-B for diagnosing sarcoidosis: The International Sarcoidosis Assessment (ISA) randomized clinical trial

Background and objective

Endosonography with intrathoracic nodal sampling is proposed as the single test with the highest granuloma detection rate in suspected sarcoidosis stage I/II. However, most studies have been performed in limited geographical regions. Studies suggest that oesophageal endosonographic nodal sampling has higher diagnostic yield than endobronchial endosonographic nodal sampling, but a head‐to‐head comparison of both routes has never been performed.

Methods

Global (14 hospitals, nine countries, four continents) randomized clinical trial was conducted in consecutive patients with suspected sarcoidosis stage I/II presenting between May 2015 and August 2017. Using an endobronchial ultrasound (EBUS) scope, patients were randomized to EBUS or endoscopic ultrasound (EUS)‐B‐guided nodal sampling, and to 22‐ or 25‐G ProCore needle aspiration (2 × 2 factorial design). Granuloma detection rate was the primary study endpoint. Final diagnosis was based on cytology/pathology outcomes and clinical/radiological follow‐up at 6 months.

Results

A total of 358 patients were randomized: 185 patients to EBUS‐transbronchial needle aspiration (EBUS‐TBNA) and 173 to EUS‐B‐fine‐needle aspiration (FNA). Final diagnosis was sarcoidosis in 306 patients (86%). Granuloma detection rate was 70% (130/185; 95% CI, 63–76) for EBUS‐TBNA and 68% (118/173; 95% CI, 61–75) for EUS‐B‐FNA (p = 0.67). Sensitivity for diagnosing sarcoidosis was 78% (129/165; 95% CI, 71–84) for EBUS‐TBNA and 82% (115/141; 95% CI, 74–87) for EUS‐B‐FNA (p = 0.46). There was no significant difference between the two needle types in granuloma detection rate or sensitivity.

Conclusion

Granuloma detection rate of mediastinal/hilar nodes by endosonography in patients with suspected sarcoidosis stage I/II is high and similar for EBUS and EUS‐B. These findings imply that both diagnostic tests can be safely and universally used in suspected sarcoidosis patients.

This global RCT in patients with suspected sarcoidosis stage I/II with an indication for endosonographic nodal sampling showed a similarly high granuloma detection rate and sensitivity for diagnosing sarcoidosis with endobronchial ultrasound versus endoscopic ultrasound‐B. The findings imply that both diagnostic tests (endobronchial/oesophageal) can be used safely and universally in suspected sarcoidosis patients.

Endobronchial ultrasound-guided transbronchial needle aspiration in sarcoidosis: Beyond the diagnostic yield

Endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) is the commonly used technique for pathological confirmation of clinically suspected sarcoidosis, mostly owing to its consistently high success rate in the detection of granulomas. However, other possible advantages, which are less appreciated and often poorly studied, may also contribute to the wider use of EBUS-TBNA in the future. These advantages include refinement of differential diagnoses through the study of lymph node characteristics during B-mode examination; reduction of complications associated with bronchoscopy, as well as improved triage of the specimen for ancillary studies with the use of rapid on-site evaluation; optimization of the quality of the sample through the selection of a target area for biopsy with minimal vascularity and absence of calcifications by using the colour Doppler and the B-mode; and prediction of the presence of extensive lymph node fibrosis by using the strain elastography module. Yet, limitations and possible clinical drawbacks should also be acknowledged. Indeed, due to the lack of specificity of the pathology findings in EBUS-derived samples, the diagnosis of sarcoidosis is one of the exclusion and should remain essentially clinical. The external validity of EBUS-TBNA results in sarcoidosis is questionable, as they mainly derive from studies in populations with a high disease prevalence. Finally, the risk exists that the low morbidity and high diagnostic yield of EBUS-TBNA may lead to its overuse in patients with clinical/radiological findings specific enough to secure a clinical diagnosis of sarcoidosis.