背景:家族性腺瘤性息肉病(FAP)是一种由种系APC突变引起的结直肠癌(CRC)易感综合征,其特征是CRC和结肠息肉的风险增加,在某些形式上,特定的突出肠外表现,即骨瘤,软组织肿瘤和牙齿异常。腓骨厚皮骨形成是一种罕见的临床实体,由腓骨远端部分的单侧弯曲和整个骨骼的伸长所定义。不影响胫骨。
方法:我们报告了一名17岁的男性,在18个月大的时候发现了由腓骨畸形(后来被描述为肥厚性骨病)和左桡骨大的外生性骨瘤引起的右腿非进行性弯曲,在15岁时注意到,没有胃肠道症状。没有相关的家族史。详细表征显示多发性骨瘤,皮肤损伤和牙齿异常,提出了FAP的假设。通过基因检测[c.4406_4409dupp.(Ala1471Serfs*17)APC基因的从头突变]和内窥镜检查(整个结肠的多个腺瘤,回肠和胃)。
结论:该病例报告提请注意FAP的骨骼表现的表型谱:该患者患有先天性腓骨畸形,以前与这种综合征无关,但这可能是该患者的首次表现。这个临床病例也说明了FAP早期诊断的挑战,尤其是没有家族史,并强调了多学科方法和对罕见骨骼异常进行充分研究的重要性。
BACKGROUND: Familial Adenomatous Polyposis (FAP) is a colorectal cancer (CRC) predisposition syndrome caused by germline APC mutations and characterised by an increased risk of CRC and colonic polyps and, in certain forms, of specific prominent extraintestinal manifestations, namely osteomas, soft tissue tumours and dental anomalies. Pachydysostosis of the fibula is a rare clinical entity defined by unilateral bowing of the distal portion of the fibula and elongation of the entire bone, without affectation of the tibia.
METHODS: We report a 17-year-old male, who presented with a non-progressive bowing of the right leg detected at 18 months of age caused by a fibula malformation (later characterized as pachydysostosis) and a large exophytic osteoma of the left radius, noticed at the age of 15 years, without gastrointestinal symptoms. There was no relevant family history. Detailed characterisation revealed multiple osteomas, skin lesions and dental abnormalities, raising the hypothesis of FAP. This diagnosis was confirmed by genetic testing [c.4406_4409dup p.(Ala1471Serfs*17) de novo mutation in the APC gene] and endoscopic investigation (multiple adenomas throughout the colon, ileum and stomach).
CONCLUSIONS: This case report draws attention to the phenotypic spectrum of skeletal manifestations of FAP: this patient has a congenital fibula malformation, not previously associated with this syndrome, but which is likely to have been its first manifestation in this patient. This clinical case also illustrates the challenges in the early diagnosis of FAP, especially without family history, and highlights the importance of a multidisciplinary approach and the adequate study of rare skeletal abnormalities.