Figure 6d.

PMP (disseminated peritoneal adenomucinosis [DPAM]) in a 50-year-old man with progressive abdominal distention, early satiety, and weight loss due to a ruptured low-grade appendiceal mucinous neoplasm (LAMN). (a, b) Axial (a) and coronal (b) T2-weighted images show heterogeneously T2-hyperintense mucin (arrowheads) surrounding the liver and stomach, with subcapsular splenic implants (* in a). Close examination of the coronal image shows marked distention of the appendix (arrow in b) with a “pear” or “chicken drumstick” appearance. (c) Photograph of the cut resected spleen shows subcapsular splenic implants (*), which correlate with those seen at MRI. (d) Low-power photomicrograph of the appendix (H-E stain) shows loss of the normal mucosal architecture with proliferation of columnar mucinous epithelial cells (arrowhead), which produce mucinous content. The mucin (*) distends the appendiceal lumen and dissects through the ruptured wall (arrows), where it implanted diffusely along the peritoneal surface, leading to PMP.