|Year : 2021 | Volume
| Issue : 2 | Page : 186-189
Familial adenomatous polyposis presenting as synchronous adenocarcinoma colon
R Sathish Kumar, B Ajay Kumar
Department of General Surgery, Government Medical College, Kozhikode, Kerala, India
|Date of Submission||11-Oct-2021|
|Date of Decision||15-Oct-2021|
|Date of Acceptance||20-Oct-2021|
|Date of Web Publication||15-Nov-2021|
Dr. R Sathish Kumar
Department of General Surgery, Government Medical College, Kozhikode - 673 008, Kerala
Source of Support: None, Conflict of Interest: None
Familial adenomatous polyposis is a genetic condition. It is diagnosed when a person develops more than 100 adenomatous colon polyps. Synchronous colon neoplasia is defined as two or more primary tumors identified in the same patient and at the same time. We report a case of a 43 year old female presenting with synchronous colon cancer and multiple adenomatous polyps.
Keywords: Familial adenomatous polyposis, intestinal obstruction, laparotomy, synchronous adenocarcinoma
|How to cite this article:|
Kumar R S, Kumar B A. Familial adenomatous polyposis presenting as synchronous adenocarcinoma colon. Kerala Surg J 2021;27:186-9
| Introduction|| |
Familial adenomatous polyposis (FAP) is defined as an inheritable disorder in which the large bowel contains multiple adenomatous polyps (typically more than 100). It is an autosomal dominant inherited cancer predisposition syndrome that is cause by genetic mutation of adenomatous polyposis coli (APC) gene located in chromosome 5q21. The incidence of the disease ranges from 1 in 5000 to 1 in 17,000 live births per year. The polyps in this condition are initially benign, but in the absence of proper surgical intervention, inevitably progresses to malignancy around the mean age range of 34–43 years.
| Case Report|| |
A 43-year-old female from Wayanad came to our casualty with complaints of abdominal pain for 1½ years, which increased over the last 3 days. She had a history of constipation for the past 3 days. She had no complaints of vomiting or abdominal distension. She had no other comorbidities and no previous surgeries. Personal and family history was unremarkable. On examinations, the patient was found to be thin built, moderately nourished. On per abdominal examination, it was soft and nontender. There was a vague mass palpable over left ileac fossa.
Blood investigations were within normal limits. X-ray abdomen showed no features of dilated bowel loops or air-fluid levels. Ultrasonography abdomen showed features suggestive of bowel wall thickening over the descending colon. Contrast-enhanced computed tomography abdomen showed two focal areas of short segment bowel wall thickening in the descending colon-sigmoid colon junction (extent of 4–5 cm and thickness of 10 mm), caecum (extent of 4 cm and thickness of 12 mm). Few enlarged lymph nodes of size 10–12 mm were noted in the pericolonic regions. Colonoscopy showed multiple pedunculated polyps, around 10 in sigmoid colon and obstructing neoplasm (large circumferential ulcerated growth with luminal narrowing at 40 cm) in sigmoid colon. Rectum was normal. CEA was 3.84 ng/ml within normal limits. Biopsy from the polyp revealed tubulovillous adenoma and sigmoid growth suggestive of well-differentiated adenocarcionoma.
The patient underwent emergency laparotomy and resection of caecum and sigmoid with ileo-colic and colorectal anastomosis under GA. The intraoperative findings were lesion in the distal sigmoid measuring 4 cm × 3 cm × 2 cm with multiple polyps noted in the cut section, infiltration into the peritoneum [Figure 1] and lesion in the caecum measuring 4 cm × 2 cm × 1 cm with multiple polyps noted in cut section. The rest of the bowel was normal. The liver was normal and no metastatic deposits were noted. The patient had an uncomplicated postoperative recovery. The polypectomy specimen showed villous adenoma with mild dysplasia. The caecum with distal ileum showed moderately differentiated adenocarcinoma of size 3 cm × 3 cm × 1.2 cm with lymphovascular emboli and tumor infiltrating into pericolic fat [Figure 2]. Sigmoidectomy specimen showed well-differentiated adenocarcinoma colon with the tumor measuring 3 cm × 1.8 cm × 0.3 cm with no lymphovascular emboli, but the tumor was infiltrating into pericolic fat [Figure 3]. The proximal and distal ends were free of tumor. 6/14 lymph nodes showed metastasis from the tumor. A total of 28 polyps were noted in the resected specimen of caecum and sigmoid colon, largest measuring 3 cm × 1.8 cm × 1 cm, histologically showing features of villous adenoma with mild dysplasia. Colonoscopy - Postprocedure after 3 months showed multiple sessile polyps in transverse colon, descending colon, and rectum. The rectal polyp showed mild edema and chronic inflammation. Descending colon polyp showed mild edema with focal dysplasia, suggestive of adenomatous polyp. The transverse colon showed focal mild dysphasia with edema and chronic inflammation. Splenic flexure showed an adenomatous polyp with moderate dysplasia [Figure 4] and [Figure 5].
|Figure 2: Cut section of caecum specimens showing lesion with multiple polyps and appendix. Largest polyps measuring 3 cm × 1.8 cm × 1 cm consistent with features of villous adenoma|
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|Figure 3: Cut section of sigmoid colon showing lesion with multiple polyps|
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| Discussion|| |
Colorectal carcinomas are mostly sporadic; only 25% are hereditary. FAP and Hereditary Non Polyposis Colorectal Carcinomas (HNPCC) account for 5% of inherited cases. Only 1% of colorectal carcinomas have an origin from FAP. Estimates of the prevalence of FAP range from 1 in 6850 to 1 in 31250 live births (2.29–3.2 cases per 100,000 individuals) with equal incidence in men and women. The first description of FAP was rendered by Chargelaigne in 1859 and its Mendelian dominant trait was documented by Harrison Cripps in 1882. The association of intestinal cancers with FAP was revealed in 1890 by Handford.
Three variants are known to occur, classical FAP, attenuated FAP, and autosomal recessive FAP or MYH associated polyposis. Classical FAP and attenuated FAP (originally called hereditary flat adenoma syndrome) are initiated by APC gene defects on Chromosome 5 while autosomal recessive FAP is caused by faults in MUTYTH gene on chromosome 1. While classic FAP presents with >100 adenomas arising in late teens or early twenties, AFAP is defined by <100 adenomas at presentation and arising in an older age group, typically between 40 and 70 years of age.,
The molecular basis of FAP is the mutation of the APC gene of the WNT signaling pathway. APC gene is located in 5q21 comprising of 15 exons coding for 310 k damultidomain protein. APC is a tumor suppressor protein which regulates transcription of a number of cell proliferation genes through its interaction with β-catenin. Germ-line mutations in APC gene, mostly nonsense or frameshift mutations resulting in a truncated protein product with abnormal function have been detected in around 80% of FAP patients, while in 20% of cases it occurs as a spontaneous mutation without prior family history., In the present case, there was no significant family history.
The most common clinical symptoms in FAP are bleeding per rectum, abdominal pain, tensesmus, and diarrhea. Anemia resulting from blood loss may be present. Our patient presented with long-standing abdominal pain. Diagnosing FAP before the development of colorectal cancer (CRC) is important for the patient as well as his family members, who may be affected and colonoscopy/sigmoidoscopy is a helpful means in doing so. In addition to numerous colonic polyps, the phenotype of FAP includes benign and malignant neoplasms in other organs. Other organs commonly involved include the stomach (fundus polyps), thyroid (papillary cancer), adrenals (nonfunctional adenomas), small intestine (adenomas or carcinomas), bones (osteomas), retinal (congenital hypertrophy of retinal pigmental epithelium), and skin (epidermoid cysts). However, the most frequent causes of death in FAP and CRC are duodenal or ampullary cancer and desmoid disease.,
Similar to cases reported by Osuagwu et al., Nzegwu et al., and Sameer et al., in our case, synchronous invasive colorectal cancer was present along with polyposis. In FAP, adenomatous polyps are usually strewn evenly throughout the colon, with slight distal colonic excess. The size of the polyps is variable, 90% adenomas are <0.5 cm in diameter and <1% of polyps are >1 cm. In our case, a total of 28 polyps were noted in the resected specimen of caecum and sigmoid colon largest measuring 3 cm × 1.8 cm × 1 cm, histologically showing features of villous adenoma with mild dysplasia. Morphologically, these polyps are mostly tubular adenomas, as in our case, indistinguishable from common or sporadic adenomas, less commonly villous, and tubulovillous adenoma. A unique histologic feature of FAP not observed in the general population is dysplastic or adenomatous epithelial cells in single crypts or even portions of single crypts designated as microadenoma.
The most common surgical intervention for FAP is proctocolectomy with ileoanal anastomosis. If FAP is associated with adenocarcinoma, the treatment is surgical resection with chemotherapy and radiotherapy depending on the stage the disease. Adenomas may develop in the ileal pouch after colectomy or small segment of the remaining rectal epithelium/anal transition zone after restorative proctocolectomy and studies reveal minor risk for cancer in these sites. So, even after surgery, endoscopic surveillance of the rectum or ileal pouch should continue yearly.
The generally accepted colon screening guideline for children at risk for classic FAP is every 1–2 years and sigmoidoscopy beginning at 10–12 years of age. However, nowadays, genetic tests have been developed where genomic DNA is isolated from the tissue/blood of the potential high-risk patients (relatives of a known case of FAP) which is then subjected to analysis of APC gene mutations. Studies are being carried out on the role of chemopreventive drugs such as Celecoxib and Sulindac for helping in regression and prevention of colonic and rectal adenomas.,
| Conclusion|| |
Hereditary cancer syndromes like FAP are rare events affecting few unfortunate families. However, early diagnosis through active surveillance in high-risk cases and timely treatment can help in avoiding subsequent complications as exemplified by our case and reducing morbidity.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient has given her consent for her images and other clinical information to be reported in the journal. The patient understands that name and initials will not be published and due efforts will be made to conceal identity, but anonymity cannot be guaranteed.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5]