Malignant peritoneal mesothelioma presenting umbilical hernia and Sister Mary Joseph’s nodule

Figure 1 Abdominal ultrasonography. Moderate amount of ascites, irregular thickening of the mesentery and peritoneum, and multiple nodules were observed.

Figure 2 Contrast enhanced computed tomography and ¹⁸F-fluorodeoxyglucose-positron emission tomography. A: Thickened peritoneum and mesentery with multiple nodules were positively enhanced by the contrast material; B: An umbilical hernia is also evident (arrow); C: A coronal image of ¹⁸F-fluorodeoxyglucose-positron emission tomography (FDG-PET) showed no localized areas of high accumulation of FDG, but mild accumulation of FDG was observed over the entire abdominal region.

Figure 3 Laparoscopy. Multiple whitish nodules were observed on the peritoneum and the mesenterium including falciform ligament of the liver with slightly muddy yellow ascites.

Figure 4 Pathological findings of the nodular lesion and the umbilical region. A: Diffuse infiltration of oval or polygon cells with acidophilic cytoplasm was observed [hematoxylin and eosin (HE), × 200]; B: Histopathology of the umbilical region showed the invasion of tumor cells into the dermis (arrows) (HE, × 40).

Figure 5 Immunohistochemical staining results. A mucus-like substance was stained positive by alcian blue staining, and was negative after hyaluronidase treatment. Staining of calretinin and CD146 (MCAM) were positive. A: Alcian blue; B: Alcian blue (after hyaluronidase treatment); C: Calretinin; D: CD146 (MCAM).