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A 29-year-old woman presents to an emergency department in Riyadh, Saudi Arabia, due to progressive abdominal pain. In addition to feeling bloated and vomiting periodically, she has not had a bowel movement in 14 days. She says she has no appetite and has lost weight, although she has not been keeping a record of the details.

Her referring physician has provided the patient with a computerized tomography (CT) scan of her abdomen and pelvis and a report noting a mass obstructing her left colon. Her medical history includes breast cancer on her mother's side of the family.

Clinical Examination

The patient looks generally unwell. Clinicians note abdominal distension, tympanic by percussion, with the rectum empty of stool. The patient has tachycardia; her heart rate is up to 120 bpm. Findings of lab tests are unremarkable except for a high carcinoembryonic antigen level (218 ng/mL).

Abdominal x-rays in both the erect and supine positions reveal multiple air-fluid levels and a dilated bowel, with no air below the diaphragm.

Clinicians put the patient on NPO (nothing by mouth) status, with intravenous hydration and nasogastric tube decompression. Review of the CT abdomen and pelvic images with the radiologist identifies a circumferential descending colon mass with multiple regional lymph nodes and proximal dilatation.

After resuscitation, the gastroenterology team is consulted, and agrees on colonoscopic stenting as emergency treatment. Colonoscopy reveals a fungating descending colon mass obstructing the lumen; multiple biopsies are taken.

Under guide wire, a 9 cm uncovered stent is inserted, and stool begins to come through it. After the procedure, clinicians obtain an erect abdominal x-ray, which shows no signs of perforation. The patient returns to normal bowel movements and an oral diet, which is well tolerated.

Treatment Decisions

The pathology report from the biopsies indicates moderately differentiated adenocarcinoma with infiltration of the muscularis mucosa. To determine staging, clinicians perform CT chest and abdominal magnetic resonance imaging, which show no evidence of metastasis. The patient is scheduled for a laparoscopic left hemicolectomy.

Surgery reveals a descending mass surrounded by inflammatory tissue. The incidental finding of an appendicular mass at the base is identified with dilated appendix and signs of inflammation. The surgical team decides to proceed with laparoscopic-assisted subtotal colectomy with ligation of the left colic, middle colic, right colic, and ileocolic arteries and primary ileocolic anastomosis.

The resected large bowel is 75 cm in length with a circumferential left colon mass. The metal stent successfully identifies and stabilizes the mass. The appendix is 6×1.5 cm, with a heterogeneous yellow-tan firm mass.

The patient recovers well following the surgery, with no complications. She is discharged on the sixth postoperative day in stable condition.

Pathology

The surgical pathology report shows a moderately differentiated left colon mass measuring 11.0 cm in greatest dimension, with invasion through the muscularis propria into the pericolic tissue. Lymphovascular invasion is noted; 28 lymph nodes are identified, all of which are negative for metastases. Left colon adenocarcinoma is labeled as pT3, N0, Mx.

The mass on the appendix is a well-differentiated neuroendocrine tumor, which is positive for chromogranin and synaptophysin. There is evidence of invasion to the serosa and mesoappendix. Lymphovascular invasion is also noted, and two of the 28 lymph nodes test positive for neuroendocrine tumor. Appendicular carcinoid is labeled as pT3, N1, Mx.

Clinicians discuss the case at a multidisciplinary tumor board meeting and in consideration of the patient's high-risk status based on the octreotide scan, decide to proceed with adjuvant chemotherapy. The scan is performed and findings are negative. Based on the postoperative review of the CT abdomen scan, the radiologist labels the appendix as a borderline appendix with no obvious appendicular mass.

One year later, the patient reports that she has completed the adjuvant chemotherapy cycles with no notable complications, and is eating normally with no problems, and is moving her bowels twice daily. Findings of follow-up CT scans and colonoscopy are unremarkable.

Discussion

Clinicians presenting this rare of a patient with synchronous colorectal cancer and carcinoid tumors note that there is an ongoing debate around treating with multiple resections or an extensive resection. As well, clinicians face the challenge of finding an optimal medical or chemo­therapy strategy to manage both malignancies.

Synchronous primary tumors refers to the appearance of two or more different histological tumors in one patient at the same time or within a period of 6 months. These cancers differ from metachronous tumors, and are diagnosed after the specified period of 6 months.

Multiple primary tumors have been reported for about 100 years; malignancies with multiple growths represented 4.7% of all reported cancer cases in 1921, and the prevalence rate has increased in recent years to a reported rate of 17% in some studies. Clinicians note that advanced diagnostic methodology resulting in longer patient survival and an increase in the number of cancer survivors may account for this phenomenon.

In the U.S., colorectal cancer is the third most common cancer in males and females, as well as the third leading cause of cancer death. In Saudi Arabia, colorectal cancer is the most common malignancy among males and the third most common in females. On the other hand, synchronous colorectal cancer and carcinoid tumors are both relatively rare, with incidence rates of only 2.6% and 0.66%, respectively, according to the National Cancer Institute's Surveillance, Epidemiology, and End Results database from 1973 to 2004, which also shows that while the incidence of all other malignancies has remained fairly stable, carcinoid tumors have been steadily increasing.

Carcinoid tumors, or well-differentiated neuroendocrine tumors, are malignant solid cells derived from neuroendocrine secretory cells, and are found most often in the bronchial or gastrointestinal systems, with the gastrointestinal tract accounting for about two-thirds of cases. Of these, the most common gastrointestinal sites are the small bowel (45%), rectum (20%), appendix (17%), and stomach (9%).

Carcinoid tumors can be classified into functioning and non-functioning types. Non-functioning tumors tend to present as an incidental mass with or without compression symptoms. Functioning tumors are associated with systemic symptoms as a result of the tumor cells' secretion of vasoactive substances, such as serotonin.

Symptoms of carcinoid syndrome -- flushing, diarrhea, bronchoconstriction, and palpitation -- tend to develop after distant metastatic cells secrete these substances into the systemic circulation. The resulting excessive levels of serotonin can also lead to myocardial and valvular dam­age.

As noted in a 2010 Canadian , management of well-differentiated neuroendocrine tumors generally involves surgical removal of all tumor cells. In cases where curative surgery is not possible, symptomatic and biochemical control may be possible through debulking surgery, radiofrequency ablation, hepatic artery embolization, somatostatin analogues, or chemotherapy.

Efforts to address two different types of malignancies simultaneously involve identifying the medical or chemotherapeutic approach that will offer the greatest therapeutic effect for both malignancies with minimal adverse effects and toxicity.

The case authors note that there has been only one report in the literature of synchronous appendicular carcinoid tumor with colon adenocarcinoma -- also in a young female with an obstructive left colon mass and an incidental finding of appendicular mass. That patient was also managed with total colectomy.

A on the debate between multiple regional resections and extensive resection in synchronous colorectal cancer suggested that extensive resection is commonly used and preferred by surgeons in the case of left and right colon lesions. However, there has been ongoing controversy about the treatment of right colon and rectum synchronous lesions, with superiority of two regional resections regarding functional bowel movements.

The case authors conclude that synchronous colorectal cancer and carcinoid tumors are rare malignancies, and the challenge is to find an optimal medical or chemotherapy strategy to manage both.

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