How a 59-Year-Old Patient’s Vigilant Surveillance Led to Timely Intervention

A 59-year-old female with synchronous stage IV rectal cancer underwent an extensive treatment plan that included perioperative chemotherapy, neoadjuvant chemoradiotherapy, low anterior resection, total abdominal hysterectomy with bilateral salpingo-oophorectomy, and partial hepatectomy. After five years of routine follow-up, a surveillance CT scan revealed a new 5.8 cm × 3.5 cm hypodense lesion in the inferior pole of her spleen. Subsequent PET imaging showed FDG avidity, suggesting metastatic disease, even though her carcinoembryonic antigen (CEA) levels remained normal.

Given these findings, a laparoscopic splenectomy was performed. Pathological examination confirmed that the splenic lesion was indeed a metastatic, moderately differentiated adenocarcinoma originating from her colorectal primary. Remarkably, splenic metastases account for fewer than one percent of all metastatic lesions, making this discovery highly unusual. This rarity is often explained by the spleen’s anatomical, histological, and immunological properties, including rhythmic sinusoid contractions, a sharp arterial angle, and robust immune surveillance that collectively hinder tumor implantation.

Six months after her splenectomy, a follow-up CT scan detected a new hypoenhancing lesion measuring 9 mm × 8 mm in the dome of the liver, and an MRI confirmed a 1.3 cm × 1.2 cm T2 hyperintense lesion concerning for metastasis. She is currently undergoing further evaluation to determine the appropriate next steps in her treatment plan, which may include surgery, chemotherapy, targeted therapies, or a combination thereof.

The case underscores the critical role of vigilant long-term surveillance in patients with a history of advanced colorectal cancer. Timely imaging allowed for the early detection of isolated splenic metastasis—a rare but significant clinical challenge. When caught early, laparoscopic splenectomy can offer a viable treatment option, with the potential to prolong survival and maintain a good quality of life.