Desmoid tumors are a manifestation of familial adenomatous polyposis (FAP), associated with mutation of the APC gene. Although considered benign tumors, desmoids can be aggressive and cause considerable morbidity. Known risk factors for desmoid tumor growth include location of mutations within the APC gene, family history of desmoid tumors, previous surgery, female gender, and pregnancy. Desmoids occur at diverse sites, commonly within the abdomen or at sites of previous surgery; thoracic desmoids are relatively uncommon. Reported here is a highly desmoid tumor-prone FAP family with a truncating mutation in the APC gene at codon 1550 (c.4648G>T) in which female siblings developed remarkably similar thoracic desmoids with highly aggressive tumor behavior during the onset of puberty, throughout adolescence, and in one sibling during and following pregnancy. Both siblings had a fatal outcome. This case underscores the potential for aggressive behavior of desmoids during adolescence and the need for close vigilance during the adolescent and young adult (AYA) age range in desmoid-prone FAP kindreds.

中文翻译：

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青少年兄弟姐妹中高度侵袭性的胸椎硬纤维瘤在 FAP 亲属中具有致命结果：需要提高对高危 AYA 的警惕性和干预。

硬纤维瘤是家族性腺瘤性息肉病 (FAP) 的一种表现，与APC基因突变有关。虽然被认为是良性肿瘤，但硬纤维瘤可能具有侵袭性并导致相当大的发病率。硬纤维瘤生长的已知风险因素包括APC基因内突变的位置、硬纤维瘤家族史、既往手术史、女性和怀孕。硬纤维瘤发生在不同部位，通常在腹部或先前手术部位；胸椎硬纤维瘤相对少见。这里报道的是一个高度易患硬纤维瘤的 FAP 家族，在APC 中有一个截断突变密码子 1550 (c.4648G>T) 的基因，其中女性兄弟姐妹在青春期开始、整个青春期以及在怀孕期间和怀孕后的一个兄弟姐妹中发展出非常相似的胸椎硬纤维瘤，具有高度侵袭性的肿瘤行为。兄妹二人的结局都是惨绝人寰的。该案例强调了青春期硬纤维瘤可能出现攻击性行为，以及在青少年和青年 (AYA) 年龄范围内的硬纤维瘤易发性 FAP 家族中需要密切警惕。