Thoracic sarcoidosis (staging)
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Thoracic sarcoidosis can be staged on a chest radiograph with implications for prognosis although HRCT and FDG-PET provide more information to help guide treatment.
Chest radiographs have been the mainstay of staging thoracic sarcoidosis for many decades with fair interobserver concordance 6. However, this system correlates poorly with symptom severity, extrapulmonary disease, pulmonary function tests and need for treatment 3. HRCT and FDG-PET can provide more information than chest x-ray to help guide treatment decisions 3.
On PA chest radiographs, sarcoidosis can be classified into five stages 1,2,6:
stage 0: normal chest radiograph
- frequency at presentation: 5-15%
stage I: hilar or mediastinal nodal enlargement only
- frequency at presentation: 25-65%
- spontaneous resolution: 60-90%
stage II: nodal enlargement and parenchymal disease
- frequency at presentation: 20-40%
- spontaneous resolution: 40-70%
stage III: parenchymal disease only
- frequency at presentation: 10-15%
- spontaneous resolution: 10-20%
stage IV: end-stage lung disease (pulmonary fibrosis)
- frequency at presentation: 5%
- spontaneous resolution: 0%
Although in general patients progress from one stage to the next, this system does not correlate particularly well with clinical severity 1,2. In fact, chest x-ray appearances are often more dramatic than functional impairment 2.
History and etymology
In 1961, Scadding published a classification system adapted from one initially proposed by Karl Warm 4. Sometimes sarcoidosis is described as being staged with Siltzbach system 3, although this paper was not published until 1967 5, and in turn, makes reference to classification systems already in place.
- 1. Chest radiology. edited by Jannette Collins, Eric J. Stern. Philadelphia : Wolters Kluwer Health/Lippincott Williams & Wilkins, c2008. ISBN:0781763142 (find it at amazon.com)
- 2. Miller BH, Rosado-de-Christenson ML, McAdams HP et-al. Thoracic sarcoidosis: radiologic-pathologic correlation. Radiographics. 1995;15 (2): 421-37. Radiographics (abstract) [pubmed citation]
- 3. Eva Criado, Marcelo Sánchez, José Ramírez, Pedro Arguis, Teresa M. de Caralt, Rosario J. Perea, Antonio Xaubet. Pulmonary Sarcoidosis: Typical and Atypical Manifestations at High-Resolution CT with Pathologic Correlation1. (2010) RadioGraphics. 30 (6): 1567-86. doi:10.1148/rg.306105512 - Pubmed
- 4. Daniel A. Culver, Robert P. Baughman. It's time to evolve from Scadding: phenotyping sarcoidosis. (2018) European Respiratory Journal. doi:10.1183/13993003.00050-2018 - Pubmed
- 5. Siltzbach L. Sarcoidosis: Clinical Features and Management. Med Clin North Am. 1967;51(2):483-502. doi:10.1016/s0025-7125(16)33069-3
- 6. Levy A, Hamzeh N, Maier LA. Is it time to scrap Scadding and adopt computed tomography for initial evaluation of sarcoidosis?. (2018) F1000Research. doi:10.12688/f1000research.11068.1 - Pubmed