The critical role of histology in distinguishing sarcoidosis from common variable immunodeficiency disorder (CVID) in a patient with hypogammaglobulinemia

Table 1 Differential diagnosis: comparison of the features of GVCVID with sarcoidosis

Parameter	GVCVID	Sarcoidosis	Comment
Clinical features
Infections	More common	Uncommon	Favours sarcoidosis
Lymphadenopathy	Common	Common	Does not differentiate
Evans syndrome	Relatively common	Exceedingly rare	Only two cases described in sarcoid: strongly favours CVID
Interstitial lung disease	Less common	Common	No obvious interstitial lung disease: favours CVID
Steroid responsive renal disease	Very rare	Described in sarcoidosis	Strongly favours sarcoidosis
Raised intracranial pressure	Rare	More common	Favours sarcoidosis
MRI showing cauda equina involvement	No reports	Very rare	Cauda equina involvement described only in sarcoidosis
Laboratory features
Switched memory B cells absent	Consistent with CVID	Reduced memory B cells	Favours CVID
Angiotensin converting enzyme levels (ACE)	ACE levels can be elevated in GVCVID	ACE levels can be normal in sarcoidosis	Non discriminatory
Absent TRECs	Favours LOCID but on MMF	Not described	Favours CVID
CSF findings: only increased protein		Cells expected	Favours CVID
Initial IgG normal but subsequent decrease, but normalised after stopping immunosuppression	Decreased	Increased	Strongly favours sarcoidosis and excludes CVID
Lymph node: disrupted architecture	Disrupted architecture in CVID	Plasma cells and germinal centres present	Strongly favours sarcoidosis

Most clinical and laboratory abnormalities can occur in both disorders. Overall the findings strongly favour sarcoidosis. The normalisation of IgG and the histological findings subsequently excluded CVID. See text for abbreviations

ISSN: 1710-1492