These nodules were discovered independently by Ludwig Aschoff and Paul Rudolf Geipel, and for this reason they are occasionally called Aschoff–Geipel bodies.

Fully developed Aschoff bodies are granulomatous structures consisting of fibrinoid change, lymphocytic infiltration, occasional plasma cells, and characteristically abnormal macrophages surrounding necrotic centres.

Initially they are surrounded by lymphocytes, macrophages, and a few plasma cells, but they are slowly replaced by a fibrous scar.

The cardiac manifestations of rheumatic fever are in the form of focal inflammatory involvement of the interstitial tissue in all 3 layers of the heart, a pathological change named pancarditis.

They are especially found in the vicinity of small blood vessels in the myocardium and endocardium and occasionally in the pericardium, and also the adventitia of the proximal part of the aorta.

Evolution of Aschoff nodules typically involve 3 stages of development all of which may be present in the heart at the same time of inspection.

Early exudative / degenerative stage the earliest sign of injury to the heart in rheumatic fever is apparent by fourth week of illness.