Adenocarcinoma Arising from a Gastric Duplication Cyst

Abstract

Gastric duplication cysts are rare congenital anomalies, and malignant transformation has only been reported in 11 cases. A healthy 57-year-old woman presented with abdominal discomfort, and computed tomography revealed a 5.8 × 6.6 × 8.2 cm mass at the gastric fundus. On endoscopic ultrasound, the mass was mostly hypoechoic with anechoic cystic cavities arising from the submucosal layer. Fine-needle aspiration was suspicious for adenocarcinoma. Surgical pathology confirmed high-grade adenocarcinoma, clear cell cytology arising from a foregut duplication cyst. Endoscopic ultrasound is underutilized in the evaluation duplication cysts and should be considered in routine workup.

Figure 1

Axial computed tomography showing a large mass projecting intraluminally at the posterior fundal aspect of the stomach.

Figure 2

Large, heterogeneous, hypoechoic mass with cystic cavities arising from the submucosal layer of the stomach seen on endoscopic ultrasound (EUS).

Figure 3

EUS-guided fine-needle aspiration sample showing dehisced atypical epithelium with malignant cytological features consistent with adenocarcinoma (100×).

Figure 4

Gross appearance of the transected duplication cyst, an endophytic submucosal mass comprised of thickened undulating mucosa and underlying layer of attenuated muscle.

Figure 5

(A) Surgical pathology of thickened mucosa from gastric duplication cyst showing high-grade dysplasia and adenocarcinoma arising in a background of hyperplastic changes with intestinal metaplasia. (B) Further sectioning of the lesion revealing multiple microscopic foci of invasive adenocarcinoma infiltrating submucosa (pathological stage pT1bN0) (100x).