Introduction

Colorectal carcinoma is a common malignancy worldwide. Thus metastasis of colorectal carcinoma are the most common cause of mortality. Most cases are asymptomatic and the diagnosis is usually made by postoperative imaging methods.¹ Most site of metastasis for colorectal carcinoma are liver, lungs and peritoneum.² Less commonly brain, bone and adrenals are effected organs. Isole splenic involvement as metastasis is very rare for colorectal cancers.³ Berge¹ reported the incidence of splenic metastasis as 7.1% in 7165 autopsy cases with various cancers although the incidence of splenic micrometastasis arising from colorectal carcinomas is reported as 6% (4.4%-colon, 1.6%-rectal) in 1019 colorectal tumors.⁴ Splenic tumors whether primary or metastatic, are unusual.⁵ Splenic metastasis arises about 1% of all metastasis and their most common primary sources are breast, lung, colorectal and ovarian carcinomas.⁶

Case Report

In 2011 a 63 year old man was referred to our surgery department because of abdominal pain and weight loss. There was a history of constipation, abdominal pain and weight loss for 3 months. Hemoglobin level was 13 and carcinoembryonic antigen (CEA) (3.09) and cancer 19.9 levels and other laboratory levels were in normal limits. Colonoscopy and computerized tomography (CT) showed us a polypoidal growth in sigmoid colon. The colonoscopic biopsy result was moderately differentiated adenocarcinoma. There was no distant metastasis in tomographic examination. We performed a left hemicolectomy in September 2011. Histopathological examination of the resected tumor was moderately adenocarcinoma extended up to pericolic lipoid tissue. There were no lymphatic or perinoural invasion. Sixteen reactional lymph nodes were found. Adjuvan chemotheraphy was given with regimen 5-florourasil for 6 months. He was followed every 3 months for the first year and every 6 months up to date. The patient has been disease-free for 5 years. Between 2011 and 2016 further imaging studies such as CT, abdominal ultrasonography and colonoscopy were normal yearly. But in 2016 a rising level of CEA (11.21) and a hyperdense solid mass (32*28 mm) in the spleen were found by CT. Any other remote organ metastases were not found both by CT and positron emission tomography scanning (PET) (Figure 1, 2).

Upon this a percutan tru-cut biopsy was performed to the splenic massand confirmed the diagnosis. Histopathological examination of the specimen showed that the tumor within the spleen was a metastasis of a adenocarcinoma. Tumor cells was CK20 and CDX2 positive and CK7 negative. A splenectomy was performed in 2016. Histopathological examination of the gross specimen showed a tumor within the spleen that a metastasis of a moderately differentiated adenocarcinoma with 3*2.5 cm dimensions. At laparatomy no recurrence and any other metastasis of solid organs and lymphadenopathy identified.

Discussion

Colorectal cancer is a common malignancy worldwide. Thus metastasis of colorectal carcinoma are the most common cause of mortality. Most site of metastasis for colorectal carcinoma are liver, lungs and peritoneum.² Less commonly brain, bone and adrenals are effected organs. Isole splenic involvement as metastasis is very rare for colorectal cancers.³ Although the spleen is one of the most vascular organ and largest organ of the reticuloendothelial system; paradoxically metastasis to the spleen is very rare.⁷ The sharp angle of the splenic artery with the celiac axis, the rhytmic contraction by the sinusoidal splenic architecture, absence of afferent lymphatics and good immunosurveillance were speculated as limiting factors of metastasis.⁸ Experimental studies have shown that when the same adenocarcinoma cells are injected into the spleen, the growth rate of these cells is much lower in the spleen in comparison to the liver. Splenic tumors whether primary or metastatic are unusual.⁵ Splenic metastases arise in less than 1% of all metastases.⁹ Berge¹ reported the incidence of splenic metastasis as 7.1% in 7165 autopsy cases with various cancers although the incidence of splenic micrometastasis arising from colorectal carcinomas is reported as 6% (4.4%-colon, 1.6%-rectal) in 1019 colorectal tumors.⁴ Careful autopsy examinations revealed microscopic splenic metastases upto 7-34% in cancer subjects.¹⁰

Diagnosis of splenic metastasis can be made by help of any current imaging studies such as ultrasonography, CT, PET scanning and magnetic resonance imaging.¹¹ CEA is the tumor marker most used in the follow up of patients with colorectal cancer.¹²

Most previously described patients with splenic metastasis from colorectal carcinoma had a disease-free survival of 3-144 months after the primary tumor.¹³ Prognosis of isolated splenic metastasis and long term survival rate is still unknown in this patients.¹¹ Splenectomy and adjuvant chemotheraohy seems to be the preferred treatment of isolated splenic metastases from colorectal carcinoma. However definitive conclusions cannot be drawn from the small number of case reports available. The present case is disease free during the 6 months of follow up. We therefore recommend clinicians pay close attention to the spleen for the early diagnosis of isolated splenic metastasis.

Ethics

Peer-review: Internal peer-reviewed.