Abstract
A 27-year-old man presented to a nearby hospital with headache and a high fever. He was referred to our internists and diagnosed with tuberculous pyothorax by imaging examination and QuantiFERONR® test. Soon after, he was started on antituberculosis agents (isoniazid, rifampicin, and ethambutol) and gradually improved. No relapse has been observed since treatment began. However, brownish macules appeared gradually on his legs 1 year ago, and have increased in number. Specimens taken from the lesions showed epithelioid cell granuloma surrounding the homogenized substance in the dermis. These findings were not sufficient for definitive diagnosis, therefore, we referred to the findings of immunochemical staining with anti-Propionibacterium acnes antibody (PAB antibody) and Ziehl-Neelsen stain. These results together with a high level of angiotensin-converting enzyme in the peripheral blood test and a negative result for the tuberculin test led to a definitive diagnosis of sarcoidosis. Recently, positivity for PAB antibody staining has been the crucial finding for differential diagnosis of tuberculosis and sarcoidosis. However, to the best of our knowledge, no study on tuberculin with PAB antibody has been published. Although the present case did not show any involvement of the tubercle bacillus in sarcoidosis, tuberculin-like clinical manifestations were of particular significance in considering the pathogenesis.
