An 84-year-old Japanese male patient was referred to our hospital for detailed examination for gastric cancer diagnosed at a routine medical check-up. Upper endoscopy was performed and an approximately 5-cm wide type 1 tumor was detected in the cardiac region of the stomach. (Fig. 1)
Biopsy showed moderately differentiated adenocarcinoma (tub2). No distant metastatic lesions were identified on enhanced abdominal computer tomography (CT) or chest CT. Laboratory data showed that tumor markers such as carcinoembryonic antigen (CEA) and carbohydrate antigen 19-9 (CA19-9) were within the normal limits. Accordingly, based on the Japanese gastric cancer treatment guideline15, total gastrectomy with D2 lymph node dissection was indicated. However, considering his older age, total gastrectomy with D1+ regional lymph node dissection was performed. The resected specimen revealed that the tumor was 48×28 mm in diameter. Histological examination showed moderately differentiated adenocarcinoma infiltrating the subserosa with metastasis to 1 of 37 regional lymph nodes (a lymph node along the short gastric artery was positive) and slight lymphatic invasion; however, no venous invasion was identified.
According to the Japanese classification of gastric carcinoma 3rd English edition16, the patient was diagnosed with pT3N1M0, ly1, v0, pStage IIB. Postoperative course was uneventful, and the patient was discharged on postoperative day 17. Adjuvant chemotherapy with oral TS-1 was recommended, according to the Japanese gastric cancer treatment guideline.15 However, considering his older age this regimen was not performed and the patient was followed-up in the outpatient clinic.
The patient was assessed according to the Japanese gastric cancer treatment guideline, which was comprised of routine physical examinations, measurements of serum tumor markers such as CEA and CA 19-9 (every three months during the five years after the surgery), thoracoabdominal computed tomography (every six months during the first three years after the surgery and once every 12 months from the fourth year onward), and upper endoscopy (one, three, and five years after the surgery).
Eighteen months later, a 2-cm solitary hypodense lesion was detected in the spleen on CT, but serum tumor markers remained within the normal limits. Twenty-three months later, serum CEA elevated to 19.9, and an abdominal CT revealed that the splenic lesion increased in size to about 5 cm. (Fig. 2)
Splenic metastasis was suspected, and 18F-2-deoxy-2-fluoro-glucose (FDG) positron emission tomography–CT (PET/CT) was scheduled to identify other metastatic sites besides the spleen. The PET-CT revealed intense FDG uptake in the spleen without involvement of other organs. (Fig. 3) Upper endoscopy and colonoscopy were also performed, and no abnormalities were identified.
We diagnosed the patient with solitary splenic metastatic tumor from gastric cancer and thought the splenectomy could be an effective treatment to eliminate the tumor even though his age was 86 at that time. Therefore, the splenectomy was performed 26 months after the first surgery.
Resected specimen showed a well-circumscribed, white, 57×51 mm in size, solid tumor located in the splenic parenchyma on cross-section. The tumor was demarcated from the splenic parenchyma without any capsule invasion. (Fig. 4) Histological examination revealed that the splenic tumor was a moderately differentiated adenocarcinoma, which was very similar to the primary gastric cancer. The immunohistochemistry result of both the gastric cancer and the splenic tumor showed positive for cytokeratin 7, CEA, and negative for cytokeratin 20, p53. These histological and immunochemical findings were consistent with primary gastric cancer and splenic tumor. Therefore, the lesion was diagnosed as metastasis from the previous gastric carcinoma.
The postoperative course was uneventful, and the patient was discharged on postoperative day 21 after the splenectomy. No chemotherapy was administered considering his age, and he was followed-up in the outpatient clinic. The patient remains well to date without recurrence and achieved five years of recurrence-free survival after splenectomy for solitary splenic metastatic lesion from gastric cancer.