A. Posterior LA after pericardial replacement. B. Macroscopic examination (6 × 3 × 1.5 cm fragment). A well-demarcated homogeneous, smooth surfaced and highly vascularized tumor (2.8 × 2.5 × 1.5 cm) was found, with clear surgical margins. C. Histological examination. Haematoxylin and eosin staining (H & E, 40x magnification) showing the “zellballen” packeting of cells, without atypia, surrounded by capillary network (blue arrow). D. Immunohistochemical analysis (40x magnification) revealed the specific neuroendocrine markers (chromogranin and synaptophysin, C & S). S-100 protein staining technique (100x magnification) revealed the sustentacular cell network (black arrow).