The notable report by Zsolway et al1 about pediatric sarcoid beautifully illustrates how elusive this diagnosis can be. When performed, the test for angiotensin-converting enzyme can be very helpful. There is a more routine laboratory test that can flag the presence of granulomatous inflammation, and that is a differential cell count which reveals a relative monocytosis. This evidence is present in case 2; values for the differential cell count are not described in case 1 but would certainly be interesting. In the absence of bone marrow problems or laboratory error, the monocyte count can be most valuable in puzzling cases of inflammation.
Needles CF. Unusual Pediatric Presentations of Sarcoidosis. Arch Pediatr Adolesc Med. 1998;152(10):1037. doi: