History:

This 31-year-old man presented with asymptomatic brown papules on the central face of 2 months duration. Drug and family history not contributory.

The cause of acne agminata is not known. It does not appear to be a tuberculid. No mycobacterial DNA has been found on PCR testing of lesions. 

Histology  Well developed lesions show central caseous necrosis surrounded by multinucleated giant cells and epitheliod cells a picture very similar to that seen with TB. Deeper sections may show a ruptured hair follicle. There is no association with the demodex in granulomatous rosacea.

View a classic virtual slide of this condition in Path Presenter