Adenocarcinosarcoma at the esophagogastric junction with long esophageal invasion: a case report

BACKGROUND: Carcinosarcoma of the esophagus or esophagogastric junction (EGJ) is a rare malignancy with both carcinomatous and sarcomatous components. There is no report of carcinosarcoma arising from the EGJ wherein the carcinomatous element was adenocarcinoma. We describe a patient with carcinosarcoma of the EGJ in which the carcinomatous element was adenocarcinoma. CASE PRESENTATION: A 52-year-old man was diagnosed with carcinoma on his EGJ after complaining of appetite loss. All tumor markers (carcinoembryonic antigen, squamous cell carcinoma antigen, alpha-fetoprotein, and carbohydrate antigen 19-9) were within the respective normal ranges. Esophagogastroduodenoscopy showed a 150-mm (100 mm esophageal side and 50 mm gastric side) type 1 tumor on his EGJ. A histopathological examination of a biopsy specimen revealed well-differentiated tubular adenocarcinoma at the gastric side; however, only necrotic tissue was noted on the esophageal side. Contrast-enhanced computed tomography did not reveal any invasion of the adjacent structures; however, it did show five swollen regional lymph nodes. (18)F-Fluorodeoxyglucose positron emission tomography with computed tomography did not reveal distant metastases. We performed thoracic subtotal esophagectomy, total gastrectomy, and two-field plus left cervical paraesophageal lymphadenectomy. Macroscopically, the lesion consisted of two components: a 7.5-cm type 2 tumor and a 9-cm type 1 tumor at the proximal end of the type 2 tumor. Microscopically, the type 2 tumor showed predominantly solid or cribriform proliferation of tumor cells with clear cytoplasm, which was moderately differentiated adenocarcinoma with enteroblastic-like differentiation. The tumor cells of the adenocarcinoma component had periodic acid-Schiff (PAS)-positive globules and were positive for sal-like protein 4 (SALL 4) and negative for α-fetoprotein (AFP) or human epidermal growth factor receptor type 2 (HER2). The type 1 tumors consisted of the adenocarcinoma-like type 2 tumor and spindle cells (sarcomatous component). Part of the sarcomatous component showed cartilage differentiation. The type 2 and type 1 lesions were continuous lesions. The epicenter of the tumor was located at the EGJ. The adenocarcinoma component was present in 10 of 27 resected lymph nodes. The tumor was diagnosed as carcinosarcoma of the EGJ. CONCLUSIONS: We report a rare patient with carcinosarcoma of the EGJ wherein the carcinomatous element was adenocarcinoma.