Figure 7 Histological features of a hydatid cyst involving the thymus. (A) Low-power photomicrograph showing multiple sections of thymic tissue with preserved lobular architecture involved by a cystic lesion (H&E, scale bar=5 mm). (B) A separate low-power view highlights the characteristic acellular laminated membranes of the hydatid cyst arranged in concentric layers (H&E, scale bar=5 mm). (C) Higher magnification reveals the interface between residual thymic parenchyma on the left and the fibrous outer capsule of the cyst on the right (H&E, scale bar=800 μm). (D) High-power image demonstrates viable thymic tissue (yellow asterisk) adjacent to multiple protoscolices (black circles) within the cyst cavity (H&E, scale bar=400 μm). (E) Closer view of protoscolices shows internal structures including hooklets (H\&E, scale bar=200 μm). (F) The inner aspect of the laminated cyst wall is lined by a germinal epithelial layer (black arrow), consistent with an active echinococcal cyst (H&E, scale bar=200 μm).