Histopathology of lymphocystis disease in gilthead seabream juveniles. A Caudal fin section with lymphocysts in several developmental stages (haematoxylin-V.O.F.); hyaline capsule (hc), nucleus (n); cytoplasmic inclusion (i); inflammatory epithelioid cells (i.e.). B Cross-section of the intestinal villi showing oedema in the mucosa (m) and inflammatory reaction in the lamina propria/submucosa (lps). The mucosal epithelium appears hyperchromatic (haematoxylin-V.O.F.). C Histological section of liver showing hepatocytes with cytoplasmic vacuolization and loss of polygonal shape (HE). D Pancreatic acinar cells (ep) exhibiting retraction and disruption of their structure (HE). E Spleen section showing numerous melanomacrophage centres (mmc) (HE). F Histological section of brain showing haemorrhagic ventricles (HE). G Histological section of kidney showing hyaline necrosis and vacuolization in the epithelial cells of renal tubules (haematoxylin-V.O.F.). Scale bars: (A) 200 µm; (B–D) 50 µm; (E, F) 100 µm; (G) 20 µm.