The patient was a 51-year-old woman with 2-month-history of epigastric pain, dysphagia, anorexia, weight loss (4 kilos over 2 months, 7.2%), and intermittent bloody vomit. At the time of admission, patient had an acute ill-looking appearance. General examination revealed marked pallor and tenderness in the epigastric region. Most of routine laboratory parameters were found to be in normal range except for the markers of hypochromic anemia: hemoglobin 6.1 g/dl, hematocrit 19%, mean corpuscular volume 85.5 fL, iron blood level 9 µg/dl, iron-binding capacity 222 µg/dl, and erythrocyte sedimentation rate 120 mm/h. The levels of tumor markers, carcinoembryonic antigen (CEA) and carbohydrate antigen (CA 19-9) were 1.1 ng/ml and 9.7 ng/ml, respectively (normal CEA<5, CA 19-9<37).
Endoscopic examination revealed a huge ulcerative lesion that infiltrated from the antrum to the mid-body with its base covered with old blood clot. A preoperative endoscopic biopsy revealed the poorly differentiated, invasive malignant round cell neoplasm (). Howerever, it did not determined specific histologic type due to severe tissue necrosis and hemorrhage. However, no definitive diagnosis could be reached using conventional H&E staining alone. For more accurate diagnosis, additional IHC stains are required. Computed tomography detected localized wall thickening in gastric body with a few enlarged perigastric lymph nodes and there was no evidence of peritoneal seeding ().
Gastrofiberscopic examination revealed a huge ulcerofungating tumor with an extensive central ulceration and a peripheral fungating mound.
Computed tomography showed diffuse wall thickening in gastric body, with a few enlarged lymph nodes.
The patient subsequently underwent palliative subtotal gastrectomy due to seeding over peritoneum, mesentery, and transverse colon and bleeding in the tumor. Macroscopically, a specimen of 12.0×10.1 cm sized exophytic mass (Borrmann type II) was found which involved the antrum and mid-body along lesser curvature. Lesions of necrosis, hemorrhage, and focal penetrated perforation were observed in the tumor ().
Macroscopic finding is an oval, relatively well-defined, ulcerofungating tumor with an extensive, excavating central ulceration and a peripheral, fungating margin.
According to pathology report, 3 metastatic lymph nodes were identified among 35 regional perigastric lymph nodes along with peritoneal seeding. These metastatic lymph nodes harbored carcinoma component (according to 6th international Union Against Cancer TNM staging system: T4, N1, M1).
The tumor showed mixed undifferentiated carcinoma and sarcoma in conventional H&E staining (). However, for no definite diagnosis could be made using conventional H&E staining alone, IHC analysis was performed. The tumor was compatible with undifferentiated carcinosarcoma which was positive for epithelial marker (cytokeratin, epithelial membrane antigen [EMA], BerEP4) and mesenchymal marker (vimentin, CD117, S100protein, CD68, smooth muscle actin, desmin) while partially being unresponsive for mesothelial marker (calretinin) (). Carcinoma component was not involved in definite adenocarcinomatous differentiation but in neuroendocrine marker (CD56, neuron specific enolase). Sarcoma component was posivitve for neurogenic, fibroblastic, smooth muscle acting differentiation.
Biphasic tumor composed of poorly differentiated carcinoma nests (left) and sarcomatous elements (right) (H&E, ×200).
Carcinoma nests stain (×400). (A) Carcinoma nests stain positively for cytokeratin, and (B) sarcomatous elements for vimentin.
These IHC findings led to a diagnosis of gastric carcinosarcoma and post-operative course was unremarkable. The patient underwent administration of taxane-based chemotherapy (cisplatin, 5-fluorouracil and docetaxel, administered at 3 week interval). After the patient had received 9th chemotherapy and lost follow up afterwards.