Isolated Splenic Metastasis With Perisplenic Artery Lymph Node Involvement More Than 10 Years After Curative Resection of Ascending Colon Cancer: A Case Report.

Splenic metastasis from colorectal cancer (CRC) is extremely rare, particularly as an isolated lesion, and most recurrences occur within five years. The presence of concurrent perisplenic artery lymph node metastases is unusual. A 71-year-old male who underwent right hemicolectomy for ascending colon adenocarcinoma (pT4aN0M0, Stage II) presented with elevated CA19-9 levels and a splenic tumor 10 years and 5 months after surgery. Imaging revealed a 9 × 8 cm splenic mass with suspected gastric wall invasion and swelling of the lymph node along the splenic artery. Positron emission tomography/computed tomography (PET/CT) confirmed high uptake in both lesions, and endoscopic ultrasound-guided fine-needle aspiration diagnosed adenocarcinoma. An open splenectomy with en bloc resection of the invaded gastric wall and No. 11p lymphadenectomy was performed. Pathology revealed a moderately differentiated adenocarcinoma in the spleen with gastric invasion and metastasis in the No. 11p lymph node. The patient recovered well after the surgery and completed adjuvant capecitabine chemotherapy. The patient remained recurrence-free six months postoperatively. This case highlights the exceptional rarity of isolated splenic metastasis appearing after more than 10 years of disease-free status, accompanied by perisplenic artery lymph node involvement. Splenic metastasis is believed to be prevented by anatomical and immunological mechanisms; however, splenectomy has demonstrated survival benefits. Concomitant lymph node metastasis suggests a potential lymphatic route of spread, and this postulated mechanism is supported by recent multicenter mapping of splenic flexural colon cancers. Splenic metastasis may occur even after long disease-free intervals, and splenectomy with lymphadenectomy can be both therapeutic and informative. Therefore, vigilance among long-term CRC survivors is warranted.