IS Case 427: Nodular sarcoidosis
Imaging Sciences URMC 2010
Publication Date: 2010-08-27
Sarcoidosis is a non-caseating granulomatous disease which causes sequestration of T lymphocytes. Patients with the disease commonly present with fever, malaise, cough, weight loss and dyspnea. Common extrapulmonary manifestations are ocular sarcoid (uveitis) and cutaneous pathology (erythema nodosum).
The disease occurs in five radiology stages: Type 0 = remission stage; Type I = ailar/mediastinal involvement; Type II = parenchymal and hilar/mediastinal involvement; Type III = parenchymal Involvement; and Type IV = end stage fibrosis. The majority of cases present with Type I or II disease and do not progress further. However, 20% of patients will progress to end stage fibrosis and can be fatal.
There are three types of parenchymal sarcoid involvement, with a reticulonodular pattern being the most common followed by an irregular pattern with areas of consolidation. Less than 2.5% of cases present as the alveolar or nodular form and the differential diagnosis includes fungal infections (i.e., histoplasmosis), lymphoma or pneumoconioses such as berylliosis and sarcoidosis. Tuberculosis is commonly included in the differential, but those cases are usually unilateral and present with effusions. All of these diseases can present as hypermetabolic foci on PET and the diagnosis must be confirmed through biopsy.
PET/CT scans have recently demonstrated increased utility in sarcoidosis. Case reports have documented the usefulness of nuclear scans in assessing steroid treatment response as early as 6 weeks after the start of therapy. Additionally, PET/CT can be used to evaluate the systemic involvement of sarcoid in other organs, such as cardiac, renal and neural involvement.
- Armstrong P, Wilson AG, Dee P, Hansell DM. Imaging of Diseases of the Chest, 3rd Ed. New York: Mosby, 2005.
- Basu S, Asopa RV, Baghel NS. Early documentation of therapeutic response at 6 weeks following corticosteroid therapy in extensive sarcoidosis: promise of FDG-PET. Clin Nucl Med. 2009 Oct;34(10):689-90. PMID: 19893402
- Helms CA, Brant WE. Fundamentals of Diagnostic Radiology, 3rd Ed. Philadelphia: Lippincott, Williams & Wilkins, 2007.