|Year : 2012 | Volume
| Issue : 2 | Page : 101-104
Familial adenomatous polyposis coli and adenocarcinoma of the colon: A silent synchronous presentation
M Srinivasamurthy, K Geethamala, B Deepak Kumar, M Sudharao
Department of Pathology, ESIC Medical College and PGIMSR, Rajajinagar, Bengaluru, Karnataka, India
|Date of Web Publication||3-Apr-2013|
Department of Pathology, ESIC Medical College and PGIMSR, Rajajinagar, Bengaluru, Karnataka
Source of Support: None, Conflict of Interest: None
Familial adenomatous polyposis (FAP) coli is an autosomal dominant syndrome characterized by germline mutation of adenomatous polyposis coli (APC) gene resulting in intestinal adenomatous polyposis and a very high incidence of transformation to colorectal adenocarcinoma. A 57-year-old male presented with watery diarrhea, pain abdomen and weight loss since 2 years. A clinical diagnosis of malabsorption syndrome was made. Upper gastrointestinal endoscopy did not reveal any lesions. Colonoscopy showed numerous polyps throughout the colon without any evidence of malignancy. Total proctocolectomy with ileostomy was done. Excised specimen showed APC with two foci of invasive adenocarcinoma in the transverse and descending colon. Studies indicate that FAP coli can transform to adenocarcinoma and hence we go by the fact that same is the scenario in our case. We present this interesting case with clinical and pathological findings.
Keywords: Adenocarcinoma, colon, familial adenomatous polyposis coli
|How to cite this article:|
Srinivasamurthy M, Geethamala K, Kumar B D, Sudharao M. Familial adenomatous polyposis coli and adenocarcinoma of the colon: A silent synchronous presentation. Arch Int Surg 2012;2:101-4
|How to cite this URL:|
Srinivasamurthy M, Geethamala K, Kumar B D, Sudharao M. Familial adenomatous polyposis coli and adenocarcinoma of the colon: A silent synchronous presentation. Arch Int Surg [serial online] 2012 [cited 2020 Feb 20];2:101-4. Available from: http://www.archintsurg.org/text.asp?2012/2/2/101/110029
| Introduction|| |
Colorectal carcinoma (CRC) is the fourth leading cause of cancer related deaths globally.  Among the inherited CRC, Familial adenomatous polyposis coli (FAP) and hereditary non polyposis colorectal cancer (HNPCC) account for 5%. FAP is an autosomal dominant disease characteried by numerous polyps in the epithelium of intestine. These polyps are benign to start with, and if no proper surgical intervention done malignant transformation is inevitable around the mean age range of 34-43 years. 
| Case Report|| |
A 57-year-old male patient presented with abdominal pain, watery diarrhea and weight loss on and off that worsen since 2 years. Past medical history of the patient revealed similar complaints since 10 years, for which he was treated symptomatically without any investigations, presuming his illness will resolve. Patient was poorly built, malnourished Body Mass Index (BMI - 18.26) and pale looking. Abdominal examination revealed vague tenderness in lower abdomen, no palpable mass or hepatosplenomegaly. There was no bleeding or mass on rectal examination. Clinical diagnosis of malabsorption syndrome was made. Laboratory examination revealed microcytic hypochromic anemia (Hemoglobin 6.8 gm%). Liver and kidney function tests were within normal limits. Serological tests for human immunodeficiency virus, hepatitis B surface antigen (HBsAG) and Venereal Disease Research Laboratory test (VDRL) were negative. Upper gastrointestinaltract endoscopy showed normal esophagus, gastric and duodenal mucosae. Colonoscopy detected numerous sessile polyps involving the entire colon extending from rectum to caecum. Hence provisional diagnosis of FAP was considered without any evidence of malignancy. Computed tomography (CT) scan showed no metastatic deposits. Detailed family history revealed no such illness in near kins. Total proctocolectomy with ileostomy was done after procurement of informed consent. Counseling for the family members regarding the hereditary nature of illness was explained.
Histopathological examination of total proctocolectomy specimen measured 100 cm with terminal part of ileum measuring 10 cm and appendix 6 cm in length. Cut surface - caecum, ascending, transverse, descending, sigmoid colon and rectum are studded with numerous sessile and pedunculated polyps numbering more than 4000, largest measuring 2 cm. Also seen were two ulcerative growths, largest of size 2.5 cm × 1.5 cm and smaller measuring 1.5 cm × 1 cm in transverse and descending colon respectively [Figure 1] and [Figure 2]. Multiple H and E stained sections showed numerous adenomatous polyps with mild to moderate dysplasia and invasive well differentiated adenocarcinoma in the transverse and descending colon extending up to serosa. Ileal surgical margin and anal verge were free of tumor infiltration. Base of appendix showed tubular adenoma [Figure 3], [Figure 4], [Figure 5]. A final diagnosis of FAP coli with synchronous invasive adenocarcinoma colon pT3cpNOpM0 American Joint Committee on Cancer (AJCC) was made. The postoperative period was uneventful and completed two cycles of chemotherapy. Follow-up of patient for 6 months and check CT scan and positron emission tomography (PET) scan showed no metastasis.
|Figure 1: Resected specimen showing numerous sessile and pedunculated polyps|
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|Figure 3: (a, b) Polyp showing tubular structure lined by epithelium with mild atypia– Adenomatous polyp (H and E, ×4)|
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|Figure 4: (a, b) Adenocarcinoma – colon, showing infi ltrating malignant glands in the muscularis externa and the subserosal layer (H and E, ×4)|
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|Figure 5: Adenocarcinoma – colon, showing infi ltrating malignant glands ×40|
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| Discussion|| |
First description of FAP was given by Chargelaigne in 1859 and its mendelian dominant trait was recognized and reported by Harrison Cripps during 1882.  In 1890 Handford mentioned the association of intestinal cancers with FAP.  Extraintestinal manifestation of subcutaneous tumors related with FAP was noted by Davic and Bussy in 1912 but later in 1953 Gardner and Richards reported the syndrome commonly known as Gardner's syndrome.  No such extraintestinal manifestations noted in our patient.
Majority of CRCs are sporadic accounting for 75% followed by inherited genetic mutations in 25%. Among inherited CRCs, FAP and HNPCC account for 5%. FAP is an autosomal dominant disease that results from mutations in adenomatous polyposis coli gene located on chromosome 5q21.22. One third of all cases of FAP have no family history of FAP and these cases are thought to be caused by new germ line mutations. 
The incidence of FAP ranges from 1 in 6000-1 in 12000 births with both sexes being equally affected. By the age of 35 years, 95% of individual with FAP have >100 adenomatous polyps. Without colectomy, colon cancer is inevitable in 100% by the mean age range of 34-43 years. , In 80% of patients with FAP there is family history of polyps and or CRC, while 20% occurrence is due to new germline mutations without prior family history, as noted in our case. ,
Osuagwu, et al. reported a case of FAP in 40 year old Nigerian with synchronous invasive colonic carcinomas and metastatic jejunal adenocarcinoma.  A similar presentation of FAP with invasive CRC was reported in a 26 year old Nigerian male by Nzegwu, et al. A rare case of advanced synchronous colorectal cancer along with liver metastasis was diagnosed concurrently with FAP involving whole of large intestine by Lakatos, et al. After an extensive review of literature a case of FAP with poorly differentiated adenocarcinoma in transverse colon in a 49 year old farmer from the valley of Kashmir was reported by Sameer, et al.
Most of the young patients present with non-specific abdominal pain, palpable abdominal mass or mass per rectum, whereas change in bowel habits, chronic bloody diarrhoea and unexplained rectal bleeding are the symptoms in elderly patients. Chronic bloody diarrhoea and rectal bleeding are associated with anemia, whereas hypoproteinemia is a late manifestation due to protein losing enteropathy and malnutrition. Therefore, clinically malabsorption syndrome is usually suspected, which was also seen in our case. Most patients are asymptomatic until colorectal cancer develops. 
Making the diagnosis of FAP before the development of CRC is important for the patient as well as his family members who may be affected. Colonoscopy and sigmoidoscopy plays an important role in diagnosing the condition, but in our case, the patient kept delaying the investigation hoping for a spontaneous resolution of the disease. Ultrasound of the abdomen, liver function tests and CT scan aids in ruling out liver metastasis and other extraintestinal manifestations, which was carried out in our case.  Genetic testing provides ultimate diagnosis in 95% of cases but the same was not carried out in our case due to financial constraints.  Counseling for the family members regarding the hereditary nature of illness was explained.
Most common surgical interventions are total proctocolectomy with ileostomy and subtotal colectomy with repeated postoperative proctoscopy. Since our patient had rectal polyps too, the earlier procedure was considered to be the best. Mostly patients with FAP are diagnosed earlier and prophylactic colectomy with repeated monitoring is done to avoid complications due to malignancy. Among them, many present with invasive carcinomas from the residual polyps or from the stumps. , In our case, since patient refused to undergo further investigations, he presented with synchronous FAP with invasive adenocarcinoma colon. The authors followed-up the patient for 6 months and check CT scan and PET scan showed no metastasis.
| Conclusion|| |
The dictum that "prevention is better than cure" and "early prevention and treatment" can be aptly applied to this entity and is remarkably expressed in the present case. With the bare fact that most of the patients harboring FAP present with non-specific abdominal symptoms and are clinically diagnosed as malabsorption syndrome. High index of suspicion and perseverant early investigations are required to avoid delay in diagnosis and treatment of FAP and its subsequent complications as exemplified in our case.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5]