Granulomatous Sarcoidosis Mimics

Abstract

Many granulomatous diseases can mimic sarcoidosis histologically and in terms of their clinical features. These mimics include infectious granulomatous diseases, granulomatous reactions to occupational and environmental exposures, granulomatous drug reactions, vasculitides and idiopathic granulomatous conditions. It is important to distinguish sarcoidosis from these mimics, as a misdiagnosis of these diseases may have serious consequences. This manuscript reviews numerous sarcoidosis mimics and describes features of these diseases that may allow them to be differentiated from sarcoidosis. Distinguishing features between sarcoidosis and its mimics requires a careful review of the medical history, symptoms, demographics, radiographic findings, histologic features, and additional laboratory data. Understanding the clinical characteristics of sarcoidosis and its mimics should lead to more accurate diagnoses and treatment of granulomatous disorders that should improve the care of these patients. As the diagnostic criteria of sarcoidosis are not standardized, it is possible that some of these sarcoidosis mimics may represent varied clinical presentations of sarcoidosis itself.

Keywords: diagnosis; drug reaction; granuloma; infection; mimics; sarcoidosis; vasculitis.

Figure 1

Chest CT scan showing sarcoidosis nodules coalescing around the bronchovascular bundle (arrow).

Figure 2

Chest CT scan showing multiple subpleural nodules from sarcoidosis (arrows).

Figure 3

CT scan showing beading of the left and right major fissures with sarcoid granulomas (arrows).

Figure 4

Chest CT scan showing a galaxy sign in sarcoidosis, where micronodules coalesce centrally into a mass lesion (circle).

Figure 5

Chest CT scan of granulomatous-lymphocytic interstitial lung disease from common variable immunodeficiency. This condition may have identical radiographic and histologic findings of sarcoidosis. Nodules are demonstrated along the bronchovascular bundle (black arrows) and a subpleural nodule (white arrow) that are commonly observed with sarcoidosis (see Figures 1, 2).

Figure 6

Chest radiograph of a patient with chronic beryllium disease showing imaging features typical of pulmonary sarcoidosis including bilateral hilar adenopathy with some calcium in lymph nodes. Reproduced with permission from Judson (52).

Figure 7

Another chest CT scan image from the same scan as Figure 6 showing peripheral and subpleural opacities. Reproduced with permission from Judson (52).

Figure 8

A lower chest CT scan image from the same scan as Figure 5 showing a mildly enlarged spleen, which is a common feature with common variable immunodeficiency.

Figure 9

(A) Lung biopsy, necrotizing sarcoid granulomatosis. Low power image (H&E stain, 40x) of nodular replacement of a region of lung parenchyma by numerous non-necrotizing granulomas with admixed mild chronic inflammation, which is different in its appearance from classic nodular sarcoidosis by the presence of a broad area of parenchymal necrosis (red arrows) and prominent vascular involvement by non-necrotizing granulomas and chronic inflammation (black arrows). (B) Inserted higher power image of the pulmonary vessel from (A) with marked mural multinucleated giant cell rich inflammation distorting and compressing the vessel wall without associated vascular necrosis.