1. Introduction

Worldwide, colorectal carcinoma represents 10-15% of all cancer and second leading cause of cancer related death. In India also, its prevalence is rising in proportion of male: female as 6.7:5.5 per 100000 populations.[1] In 2007 World Cancer Research Fund reported epidemic of colorectal cancer as a major public health problem due to adaptation of modern lifestyle. Changed dietary pattern, sedentary lifestyle, smoking, increased lifespan and genetic susceptibility are predisposing factors for development of colorectal cancer.[2] In context of location, 75% of carcinoma of colon occurs in the left colon, 22% in right and only 3% in the caecum.[3]

Patients with carcinoma of the colon have chances of synchronous multiple malignant lesions with a reported incidence ranged between 2.3-12.4%.[4] Double malignancies of the gastrointestinal tract are very rare. In a review of more than 2000 patients, Minni et al. found the incidence of a second primary tumor in the gastrointestinal tract to be 4.3%. This association most often occurs in patients with familial cancer syndromes.[5] It is a significant clinical entity and if detected early results in a better outcome. Otherwise second malignant lesion with metachronous presentation poses significant problems in management. We report a case of synchronous adenocarcinoma of caecum and sigmoid colon managed successfully at our center.

2. Case Presentation

A 58 year old man presented with complaints of pain in the abdomen and black colored stools over the last six months. Clinical examination revealed the existence of a palpable mass in right iliac fossa as well as in left iliac fossa. On acquisition of detailed history, personal and family history of malignancy of the gastrointestinal tract was not significant. Patient was pale with hemoglobin 7.2g/dL and all other biochemical and hematological parameters were within normal limit. Ultrasound sonography (Figure 1 and 2) and computed tomography revealed irregular circumferential thickening in caecum and sigmoid colon suggestive of malignancy without evidence of distant metastasis.

On colonoscopy growth in the region of sigmoid colon was observed and biopsy was taken. (Figure 3) Further colon could not be visualized because of the presence of mass. Biopsy of colonic growth revealed presence of malignant cells suggestive of moderately differentiated adenocarcinoma.

Figure 1. Ultrasound examination showing mass in right iliac region

Figure 2. Ultrasound examination showing mass in left iliac region

Tumor marker serum carcinoembryonic antigen was raised to 155 ng/ml. After careful preoperative evaluation patient was scheduled for laparotomy. On exploration, we observed synchronous double malignancies involving caecum and sigmoid colon. So with right hemicolectomy and end to end anastomosis between the ileum and transverse colon mass in caecum was excised. (Figure 4) For resection of mass in the sigmoid colon, left hemicolectomy with end to end anastomosis between transverse colon and rectum performed. Intraoperative colonoscopy revealed segment of normal colon in between two tumors.

Macroscopic examination of mass from caecum showed cauliflower like growth of size 7x4x2 cm. Histopathological examination of the tumor from caecum (Figure 5)revealed glandular structures formed by large columnar to cuboidal cells having large hyperchromatic pleomorphic nuclei. It was diagnosed as moderately differentiated adenocarcinoma invading muscle coat and serosa with stage II (T₃N₀M₀).

Figure 3. Growth observed in the sigmoid colon during colonoscopy

Figure 4. Specimen of resected growth with segments of the large bowel

Figure 5. Histological examination of moderately differentiated adenocarcinoma from caecum

Specimen of sigmoid colon had cauliflower like growth of size 6x4x2 cm and its microscopic examination (Figure 6) diagnosed it as moderately differentiated adenocarcinoma invading muscle coat and serosa with stage II (T₃N₀M₀).

Figure 6. Histological features of moderately differentiated adenocarcinoma from sigmoid colon

All 12 paracolonic lymph nodes, omentum, borders of cut margins of colon and appendix were free of tumor metastasis. Ideally immunohistochemistry analysis and molecular study of both tumors should have been performed in our case. But such facilities are not available at our center and patient was not willing for further evaluation.

In post-operative phase patient developed severe pneumonitis, this was managed by antibiotics and mechanical ventilatory support. Then he had diarrhea for 10-12 days leading to electrolyte imbalance, dehydration and low grade fever with weight loss. Patient developed pancytopenia with hemoglobin 3.4gm/dL, white blood cell count 3,600 cells/mm³ and platelets 46,000 and normal bone marrow cytology. In view of pancytopenia patient received two units of blood transfusion. After three weeks patient was evaluated and found to be fit for initiation of adjuvant chemotherapy and received six cycles.

3. Discussion

Multiple primary cancer is defined as occurrence of two or more different primary malignancy in same or different organs synchronously or metachronously. Phenomenon of multiple primary tumors was first described by Billroth and further by Warren and Gates.[6] Colon is the most commonly affected organ by multiple tumors. 32% of cases of multiple tumors localize in the large intestine.[7]

In our case risk factors recognized for carcinoma of colon were smoking, consumption of nonvegetarian food and Diabetes Mellitus. Personal and family history did not contribute any further information. Yuhara et al concluded in their meta-analysis Diabetes Mellitus as an independent risk factor for colorectal cancer.[8] Multiple primary colorectal cancers are predominantly observed in males. Common sites of multiple primary colorectal cancers are the sigmoid colon and rectum. The aetiopathology of coexisting multiple tumors remains unclear, but it has been hypothesized that they can arise from tissues with similar embryological origin when they get simultaneously exposed to carcinogens or hormones.[9]

Our case fulfills the criterion reported by Cunliffe et al who described synchronous adenocarcinoma as two or more in number detected either pre or intraoperatively, or postoperatively within 6 month. They should be distinctly separated by at least 4 cm distance, and they should not consist of submucosal spread or a satellite lesion of each other.[10] In the present report 58 year old man with synchronous adenocarcinoma in the caecum and sigmoid colon with the existence of normal colonic mucosa between two neoplasms is desribed. On colonoscopy visualization of bowel beyond sigmoid colon was not possible due to the presence of tumor. During laparotomy coexistence of both tumors was observed and they were excised with two segment resection.

Joo Won Yoon and colleagues identified 26 cases with multiple primary colorectal tumors among 1669 patients. Six of them with synchronous lesions were treated with two segment resection of colon as we managed our case.[11]Masatoshi Oya et al reported 4.8% cases of synchronous colorectal carcinoma predominantly in males associated with a short post operative survival compared to cases with single lesion.[4] Prognosis depends on deeper wall penetration, lymph node metastasis, distant metastasis and advanced pathological stage. Some studies reported lesions predominantly in the left colon in contrast to some studies with a predominance in the right colon.[12, 13]

Preoperative careful evaluation for the presence of multiple malignant lesions can be achieved with the help of optical colonoscopy, intraoperative palpation and colonoscopy, barium enema and colonoscopy. Intraoperative thorough examination of total colon is a crucial step to avoid missing of coexisting tumors and subsequent operative procedures. Chen et al reported 66% cases of synchronous cancers were missed in preoperative examination.[12] Po-Li Tsai and associates reported significantly higher mortality in synchronous cases than single cancer.[14] Synchronous adenocarcinoma in the colon has been described only in one case report by Gruia et al. They observed flat type of adenocarcinoma in the caecum and mucinous adenocarcinoma in the sigmoid colon.[15] Various reports described coexisting multiple tumors in colorectal region with other organs. To our best knowledge ours is the second case report of synchronous adenocarcinoma of sigmoid colon and caecum.

Thorough clinical and radiological evaluation is necessary in patients with colorectal cancer. If multiple lesions are missed, they present as early metachronous carcinoma in advanced stage. Present case report emphasizes the necessity of careful evaluation for detection of additional cancers.

Conclusion: Complete perioperative evaluation of the colon is necessary to identify multiple malignant lesions. Surgeon should be alert and always be aware of possibility of multiple tumors in the colon to avoitd he second surgery for missed lesion to secure best prognosis.

ACKNOWLEDGMENTS

The author reports no conflicts of interest in this work.