Fig. 2a–f

Macroscopic and microscopic histopathological findings of AA. a Extraintestinal angiostrongyliasis in liver with multiple small nodules (black arrowheads) and yellowish material. b Small bowel showing a segmental Crohn disease-like lesion with wall thickening and hemorrhagic area (black arrowheads). c Transversal section of Angiostrongylus costaricensis adult female worm inside a branch of the mesenteric artery showing polymyarian musculature (black arrowhead), uterus with an egg inside (red arrowhead) and gut (blue arrowhead). Muscle cells of the artery are shown by a black star [hematoxylin–eosin staining (HE), ×200]. d Angiostrongylus costaricensis egg (black arrowhead) inside a small vessel surrounded by severe eosinophilic infiltration (HE, ×400). e Eosinophilic infiltration in the liver of a patient with AA (HE, ×400). f Granuloma with histiocytes (blue arrowheads), giant multinucleated cells (black arrowhead) and eosinophils (red arrowheads) (HE, ×400)