PMC3087427_01
CT scan (coronal view) of the abdomen and pelvis showing an appendiceal mucocele with intraluminal gas and wall edema.
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April of 2010, she presented to our institution with symptoms of acute appendicitis. A CT scan of the abdomen and pelvis revealed inflammatory changes and gas in the wall of the distended appendix (Figure 1).
Gross examination: cross-section of appendix, lobulated green/brown partially hemorrhagic, and pigmented tumor occupy the proximal portion of the appendiceal lumen.
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The tumor was soft, pink/tan in the distal aspect, and lobulated green/brown in the proximal portion (Figure 2).
Microscopic examination: (a) solid cords and nests of tumor cells fill the appendiceal lumen and replace the appendiceal mucosa and submucosa with partial extension to the muscularis, no involvement of the serosa; (b) tumor cells with abundant eosinophilic cytoplasm, some of which are vacuolated, with pleomorphic nuclei, prominent nucleoli, and atypical mitosis (Hematoxylin and eosin staining, (a) x200; (b) x400). (c) Tumor cells strongly express HMB45, and (d) S-100 (HMB45 and S-100 immunostaining, x400).
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The lesional cells formed nests and cords and had an abundant eosinophilic cytoplasm with mildly pleomorphic nuclei and prominent nucleoli, some of which had intranuclear inclusions (Figures 3(a) and 3(b)). Antigen (M; HMB45; Enzo; New York), Melan-A (M; A103; Cell Marque; California), and S-100 (P; DAKO; California) (Figures 3(c) and 3(d)). Acute appendicitis and periappendicitis were also present.