Sarcoidosis with Caseating Granulomas and Little Red Rods

The paradigm that mycobacterial granulomas are caseating and sarcoid granulomas are noncaseating can lead to a quandary when faced with the patient with classic neurosarcoidosis symptoms but mediastinal lymph nodes with caseating granulomas. We present a case of a 47-year-old man who presented with classic neurosarcoidosis symptoms, negative quantiferon gold test, and negative standard mycobacterial culture, but had caseating granulomas and clusters of red rods on acid-fast special stain in his excisional mediastinal lymph node biopsy. With a differential between sarcoidosis and mycobacterial infection, treating for one condition could worsen the other. We review the numerous contradictory test results and their significance based on the literature. Deviations from expected results should be kept in mind, especially due to the very significant treatment differences for infectious versus inflammatory conditions