Case 131. Paragonimus miyazakii infection of brain (36 y-o M)
    Biopsy from the necrotizing brain lesion in a patient who ate Japanese freshwater crab (Geothelphusa dehaani)    
Key words : Paragonimus miyazakii, ectopic infestation
The necrotic brain parenchymal lesion is presented (HE, low power). In spite of multiple step sectioning, no adult worm was identified.   At the periphery of necrotic lesion, a few ova, about 60 μm in length, are identified (HE, higher power). Ova are also seen in the subarachnoid space.
Skin reaction to Paragonimus antigen
Positive skin reaction is suggestive of ectopic cerebral paragonimiasis (gross findings).. P. miyazakii is paratenic to the human, so that maturation of the fluke is incomplete. Therefore, the number of ova is limited and the immature adult worm tends to be absorbed easily. Refer also to case 94.
  Soap bubble sign in cerebral paragominiasis
Head roentgenograph demonstrates a large, demarcated frontal lobe lesion with bubbly appearance. Calcification is discerned. Allegedly, the soap bubble sign is suggestive of paragonimiasis westermani.. Brain metastasis of P. westermani leads to serious CNS symptoms. Infection is mediated by eating raw Japanese mitten crab (Eriocheir japonica de Haan) carrying metacercaria.
Reference case 131A
An encapsulated brain lesion filled with calcified large-sized ova, indicating ectopic cerebral parasitosis of P. westermani (HE).. The fact that such a large number of eggs are clustered locally excludes the possibility of infestation of P. miyazakii and Schistosoma japonicum.