Stormorken Astrid Tenden, Berg Thomas, Norum Ole-Jacob, Hølmebakk Toto, Aaberg Kristin, Steigen Sonja E, Grindedal Eli Marie
Section of Inherited Cancer, Department of Medical Genetics, Oslo University Hospital, Oslo, Norway.
Clinical Pathology, University Hospital of North Norway, Tromsø, Norway.
Fam Cancer. 2018 Oct;17(4):539-543. doi: 10.1007/s10689-018-0072-8.
Familial adenomatous polyposis (FAP) is usually caused by germline mutations in the adenomatous polyposis coli (APC) gene. The classic form is characterized by hundreds to thousands of adenomas in the colorectum and early onset colorectal cancer (CRC) if left untreated. FAP is also associated with multiple extra-colonic manifestations such as gastroduodenal polyps, osteomas, epidermoid cysts, fibromas and desmoids. Most desmoid tumours in FAP patients occur intra-abdominally. Approximately 15-20% of the APC mutations are de novo mutations. Somatic mosaicism has been reported in some sporadic cases of polyposis but is probably an underestimated cause of the disease. This case report presents the detection of a mosaic APC mutation in a 26-year-old woman who as a child had been diagnosed with desmoid type fibromatosis. FAP was suggested when she presented with extensive extra abdominal fibromatosis. Our findings indicate that APC mutations may be suspected in patients presenting with a desmoid regardless of its location. If there is clinical evidence that the patient has FAP, adenomas and colonic mucosa in addition to leukocyte DNA should be included in the screening, preferably using methods that are more sensitive than Sanger sequencing.
家族性腺瘤性息肉病（FAP）通常由腺瘤性息肉病 coli（APC）基因的种系突变引起。经典形式的特征是结肠直肠中有数百至数千个腺瘤，如果不治疗，会早期发生结直肠癌（CRC）。FAP还与多种结肠外表现有关，如胃十二指肠息肉、骨瘤、表皮样囊肿、纤维瘤和硬纤维瘤。FAP患者的大多数硬纤维瘤发生在腹腔内。大约15%-20%的APC突变是新发突变。在一些散发性息肉病病例中曾报道过体细胞镶嵌现象，但这可能是该疾病一个被低估的病因。本病例报告介绍了一名26岁女性的镶嵌APC突变检测情况，该女性儿童时期被诊断为硬纤维瘤型纤维瘤病。当她出现广泛的腹部外纤维瘤病时，怀疑患有FAP。我们的研究结果表明，无论硬纤维瘤位于何处，出现硬纤维瘤的患者都可能怀疑存在APC突变。如果有临床证据表明患者患有FAP，除白细胞DNA外，腺瘤和结肠黏膜也应纳入筛查，最好使用比桑格测序更敏感的方法。
