PMC6949453_01
Computed tomography (CT) of the lesion. a) The coronal view at the referral showed a lesion consisting of a cystic component and an ill-enhanced solid component, located between the stomach and the pancreas tail. b) The coronal view at four months of follow-up showed that the cystic lesion had increased in size.
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C-reactive protein, 0.01 mg/dL; carcinoembryonic antigen (CEA), 1.3 ng/mL; and carbohydrate antigen 19-9 (CA19-9), 3 IU/mL. Computed tomography (CT) demonstrated a well-demarcated lesion consisting of a heterogeneous solid component and a round cystic component, 5 cm in size, widely attached to both the remnant stomach and the pancreas (Fig. 1a). Careful follow-up was performed for four months, and CT showed the enlargement of the cystic lesion (Fig. 1b).
Endoscopic ultrasonography (EUS) scan from the stomach showing a slightly echogenic solid component (arrows) and an anechoic cystic lesion.
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Endoscopic ultrasonography (EUS) of the stomach showed a variable echogenic solid component and an anechoic cystic component (Fig. 2).
18F-Fluorodeoxyglucose-positron emission tomography (FDG-PET) demonstrating a weak uptake of FDG at the lesion (SUVmax: 3.1).
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The inside of the cyst was clear without debris. 18F-Fluorodeoxyglucose-positron emission tomography (FDG-PET) demonstrated a weak uptake of FDG at the lesion [maximum standardized uptake value (SUVmax): 3.1] (Fig. 3).
Computed tomography (CT) before distal gastrectomy against early-stage gastric cancer three years earlier showing no cystic lesion.
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As the post-gastrectomy CT images demonstrated no obvious lesion at the corresponding site (Fig. 4), a tumor with aggressive oncological potential was suspected, such as a gastrointestinal stromal tumor with cystic degeneration.
Pathology of the resected tumor. a) A gross section showed that the tumor was widely attached to both the remnant stomach and the pancreas and contained a heterogeneous solid component and an adjacent cystic component. b) An Hematoxylin and Eosin staining section showed spindle cells, collagenous stroma, and vessels (x200). c) The cystic wall was covered by flattened columnar epithelium (x200). d) Immunostaining of beta-catenin showed intranuclear expression in the fibromatosis cells (x200).
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The mass adhered strongly to the gastroduodenal anatomy and pancreatic parenchyma, measuring 75 mm in size (Fig. 5a). Histopathology showed spindle cell proliferation in the background of abundant collagenous stroma (Fig. 5b) and epithelial cells lining the cyst (Fig. 5c). An immunohistochemical study showed the tumor cells to be positive for cytoplasmic muscle specific actin (MSA) and intranuclear beta-catenin (Fig. 5d) but negative for CD34 and S-100.