Lung: histoplasmosis

Histoplasmosis This image shows an old primary infection lesion of pulmonary histoplasmosis, at low power. The lesion is well demarcated from the lung tissue. The centre is fibrotic and necrotic, and stained red. There is calcification within this. This primary lesion contained residual infectious yeasts. When the patient became infected with HIV, the histoplasmosis recrudesced and the patient died with disseminated infection. H&E stain.