PMC4908310_01
Series of abdominal computed tomography scans of the gastric duplication cyst. A cystic lesion was located between the stomach and the spleen in 2009. It expanded slightly in 2011. In 2012, some nodules emerged. In 2013, the number of nodules had increased (red arrows) and the wall was thickened with calcification (blue arrows).
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Computed tomography also revealed the cyst, which was well-defined and had a homogeneous density (Fig. 1a). We followed up this large cyst every 6 months with computed tomography because the patient was asymptomatic (Fig. 1b). At 47 years of age, she was still asymptomatic, but computed tomography revealed mural nodules in the cyst (Fig. 1c) and an increased CA19-9 concentration of 167.1 U/ml. Computed tomography and ultrasonography showed an increased number of mural nodules containing calcification, but the cystic lesion had slightly decreased in size (Fig. 1d).
Complete resection of the duplication cyst and wedge resection of the stomach. The cyst was attached to the greater curvature of the stomach (blue arrows) and was 10 cm in diameter. The cyst had a granular lumen (red arrows) and variable wall thickness with calcification.
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Gross pathology showed a 10.0 x 9.5 x 8.0 cm unilocular cystic mass adherent to the greater curvature of the stomach (Fig. 2a). The cyst was granular and had a relatively uniform thickness except for six mural nodules that projected into the cystic lumen (Fig. 2b).
Microscopic examination of the duplication cyst. (a, b) The mural nodule comprised an adenocarcinoma and atypical epithelium proliferating in a tubular or papillary pattern. (c) The surface of the cyst was also covered by hyperchromatic adenocarcinoma cells (red arrows). Just beneath the surface, however, there were a few non-neoplastic gastric glands consisting of columnar cells with mucin-containing pale cytoplasm and bland nuclei (blue arrows). (d) The glands were immunohistochemically positive for MUC6. No heterotopic tissues such as pancreas, ciliated epithelium, or cartilage were detected. Scale bars represent 5 mm in (a), 500 mum in (b), and 100 mum in (c) and (d).
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Microscopic examination showed that the cyst was located in the muscularis propria of the stomach and that the mural nodules were composed of moderately differentiated adenocarcinoma (Fig. 3a and b). The adenocarcinoma cells invaded the whole thickness of the cyst wall and serosa of the stomach and extended laterally on the surface of the cyst (Fig. 3c, red arrows). However, a few non-neoplastic gastric glands were found in a small part of the cyst wall (Fig. 3c, blue arrows). Immunohistochemical studies revealed that MUC expression in the epithelium was consistent with that of the gastric glands: positive for MUC5AC and MUC6 and negative for MUC2 (Fig. 3d).