HEREDITARY NONPOLYPOSIS COLORECTAL CANCER (HNPCC) - CASE REPORT

Case Presentation A 25-year-old female patient, with no comorbidities, was admitted to a tertiary unit reporting altered bowel habits and reduced stool volume. She disclosed a family history of colorectal cancer, including her mother diagnosed at 38 years, an uncle diagnosed at 54 years, and two cousins diagnosed at 40 and 32 years, all on the maternal side. A colonoscopy revealed a vegetative lesion in the splenic flexure, ulcerated with areas of necrosis, causing approximately 80% luminal narrowing, rendering the lesion impassable. Contrast-enhanced abdominal computed tomography showed a segmental annular wall thickening at the splenic flexure, significantly narrowing the intestinal lumen, with associated densification of the pericolic fat plane, without significant thickening of the left laterocoronal fascia, and an extension of approximately 7.0 cm. On physical examination, the abdomen was slightly distended, with no palpable mass. The histopathological diagnosis of the splenic flexure lesion confirmed invasive adenocarcinoma. Considering the diagnosis of Hereditary Nonpolyposis Colorectal Cancer (HNPCC), the patient underwent a total colectomy with terminal ileorectal mechanical anastomosis and retroperitoneal lymphadenectomy without complications. The postoperative period was uneventful, and histopathological analysis of the surgical specimen revealed invasive adenocarcinoma with staging of pT3; pN0, with 42 lymph nodes evaluated. Immunohistochemistry (IHC) results were positive for CDX2, CK20, CK7, chromogranin, synaptophysin, and CD56. The patient was referred to oncology for joint follow-up.

Discussion HNPCC is characterized by reduced or absent activity of mismatch repair (MMR) proteins. Its diagnosis is predominantly clinical, relying on detailed assessment of a positive family history and the use of Amsterdam criteria, with genetic testing less commonly applied in clinical practice. This genetic syndrome is associated with a higher incidence of metachronous and synchronous tumors compared to sporadic colorectal cancer, often necessitating total colectomy as the treatment for patients diagnosed with HNPCC.

Conclusion Characterizing the clinical-epidemiological aspects is crucial for clinical suspicion and early diagnosis of hereditary nonpolyposis colorectal cancer, enabling effective family monitoring and appropriate treatment.

 

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No conflict of interest has been declared by the author(s).

Publication History

Article published online:
25 April 2025