blue bodyGynecologic cytology
see Blue globule.
A nonspecific product of macrophage metabolism, consisting of laminated, extracellular, birefringent and ovoid 15–20 µm structures composed of calcium carbonate (per microanalysis and energy-dispersive X-ray analysis) and an outer rim of iron, adjacent to or surrounded by hyperactive macrophages, and corresponding to extruded autophagosomal residual bodies. By H&E stain, they are blue-grey; by PAS, red-purple. Blue bodies were first described in diffuse interstitial pneumonia, but can occur in any accumulation of alveolar macrophages, and are linked to mechanical obstruction (e.g., tumour), overrecruitment of macrophages or defective macrophage clearance.
Pulmonary alveolar microlithiasis, mineral dusts, fungal spores, desquamative interstitial pneumonia, destructive inflammatory processes, corpora amylacea (pink), concoidal bodies in sarcoid granulomas, pulmonary malakoplakia (numerous histiocytes), chronic inflammation, Michaelis-Guttmann (much smaller than blue bodies and more uniform).