Supplementary Material for: Delayed Presenting Gastric Duplication Cyst Mimicking a Left Adrenal Cyst in a Young Female: A Case Report with a Literature Review

Gastric duplication cyst (GDC) is a rare congenital anomaly of the gastrointestinal tract (GIT). Its misdiagnosis with different diseases is common, however, mimicking or misdiagnosing a GDC as an adrenal cyst has rarely been reported. We report a case of GDC in a young female that was mimicking an adrenal cyst. A 17-year-old female presented with chronic epigastric pain, nausea, and intermittent vomiting. Physical examinations revealed mild tenderness in the epigastric region without abdominal distention, organomegaly, or striae. Oesophagogastroduodenoscopy showed non-significant findings. Transabdominal ultrasound revealed a well-defined, hypoechoic left adrenal cystic lesion. A contrast-enhanced computed tomography scan of the abdomen and pelvis showed an oval-shaped left adrenal cystic lesion measuring 33 x 26 mm. A magnetic resonance imaging scan also confirmed the previous findings. Preoperative blood investigations and hormonal assessment were normal. Laparoscopy was performed and the surgeon intraoperatively noticed that the cyst was originating from the greater curvature of the stomach. The left adrenal gland was normal. An intra-operative consultation with a gastrointestinal surgeon was done, and wedge resection of the cyst was performed. Histopathology confirmed the gastric duplication cyst. The major characteristics for diagnosing GDC include the following: The cyst wall is continuous with the stomach; the cyst is surrounded by a smooth muscle shared with the stomach; both share the same blood supply; and the cyst wall is lined by a benign epithelium. GDCs are rare congenital malformations that may become symptomatic during adulthood. They can mimic adrenal cysts, which may lead to misdiagnosis.

胃重复囊肿（Gastric duplication cyst, GDC）是一种罕见的胃肠道（gastrointestinal tract, GIT）先天性畸形。该病常被误诊为多种不同疾病，但将其误诊为肾上腺囊肿（adrenal cyst）的案例鲜有报道。本文报告1例表现为肾上腺囊肿的胃重复囊肿病例。

患者为17岁女性，因慢性上腹痛、恶心及间歇性呕吐就诊。体格检查显示上腹部轻度压痛，无腹胀、器官肿大或皮纹异常。食管胃十二指肠镜（Oesophagogastroduodenoscopy）检查未见明显异常。经腹超声可见边界清晰的左侧肾上腺低回声囊性病变。腹部及盆腔增强计算机断层扫描（contrast-enhanced computed tomography, CT）显示大小为33×26mm的椭圆形左侧肾上腺囊性病变。磁共振成像（magnetic resonance imaging, MRI）亦证实了上述影像学表现。术前血液检查及激素评估结果均正常。

遂行腹腔镜手术（Laparoscopy），术中医师发现该囊肿起源于胃大弯（greater curvature of the stomach），左侧肾上腺外观正常。术中邀请胃肠外科医师（gastrointestinal surgeon）会诊，并行囊肿楔形切除术（wedge resection）。术后组织病理学（Histopathology）检查确诊为胃重复囊肿。

诊断胃重复囊肿的核心特征包括：囊肿壁与胃组织延续；囊肿被与胃共有的平滑肌包绕；二者具有相同的血供；囊肿壁衬有良性上皮。胃重复囊肿为罕见先天性畸形，可在成年后出现症状，其影像学表现可与肾上腺囊肿相似，从而导致误诊。