Desmoid tumors are locally aggressive, benign neoplasms originating in connective tissues. Although the exact pathophysiology remains unknown, antecedent trauma or surgery are believed to be important contributing factors. The occurrence of paraspinal desmoid tumor in pediatric patients is extremely uncommon. Here, we present an exceedingly rare case of a pediatric patient with no surgical or family history who developed a paraspinal desmoid tumor. A 9-year-old female patient presented with 4 months of progressive back pain, right lower extremity weakness, and numbness. Spinal imaging revealed a left epidural paraspinal mass compressing her thoracic spinal cord and extending into the left thoracic cavity. A multidisciplinary approach with neurosurgery and thoracic surgery enabled gross total resection of the lesion. The patient had complete resolution of her symptoms with no signs of residual tumor on postoperative imaging. Pathology revealed a desmoid tumor that avidly stained for beta-catenin. On her last follow-up, she developed a recurrence, to which she was started on sorafenib therapy. Desmoid tumors are rare connective tissue neoplasms that often occur after local tissue trauma, such as that caused by surgery. This report presents a rare case of a pediatric paraspinal desmoid tumor that occurred in a patient with no surgical or family history. Such tumors should undergo surgical resection for symptomatic relief and tissue diagnosis. Close clinical and radiographic surveillance are essential in these patients due to the high recurrence rates of desmoid tumor.

Cribriform-morular thyroid carcinoma is a rare type of thyroid cancer. It has a strong association with familial adenomatous polyposis (FAP), a hereditary genetic disorder that predisposes individuals to the development of numerous polyps in the colon and rectum. We describe the case of a young female patient who presented with an enlarging goiter, notably without detectable thyroid nodules or masses on ultrasound, who after total thyroidectomy was found to have cribriform-morular thyroid carcinoma. This diagnosis led to genetic testing and diagnosis of FAP syndrome. We demonstrate that this rare thyroid carcinoma may present with nonsuspicious findings on sonographic evaluation while being a valuable harbinger in the diagnosis of FAP syndrome.

UNASSIGNED: Cribriform-morular thyroid carcinoma (CMTC) was considered a variant of papillary thyroid carcinoma (PTC) but is a separate entity in the 2022 World Health Organization classification. CMTC has an association with familial adenomatous polyposis (FAP). Our objective is to report a case of CMTC who was subsequently diagnosed with FAP, to highlight these associated entities and implications for management.
UNASSIGNED: A 15-year-old female with a history of iron-deficiency anemia and alpha-gal syndrome presented with several years of goiter and dysphagia. She also noted unintentional weight loss, abdominal pain, melena and hematochezia, and symptomatic anemia. Physical examination was significant for multiple thyroid nodules. Laboratory results revealed normal thyroid function and iron deficiency. Multiple nodules were visualized on thyroid ultrasound, and fine needle aspiration biopsy was consistent with PTC. Total thyroidectomy was performed with a revised diagnosis of multifocal CMTC, with administration of adjuvant radioactive iodine due to persistent disease. Genetic testing confirmed FAP and she was referred for upper endoscopy, colonoscopy, and an evaluation for colectomy.
UNASSIGNED: There are no best practice guidelines for management of CMTC. Management of CMTC is guided by FAP status; sporadic cases can be managed with hemithyroidectomy, while FAP-associated cases are better managed with total thyroidectomy. Recurrence is usually managed with surgical resection. The decision to treat with adjuvant radioactive iodine is often extrapolated from management of classic PTC.
UNASSIGNED: Thyroid carcinoma in the setting of extensive family history of colorectal carcinoma should arouse suspicion for CMTC. Patients with CMTC should receive a referral for colonoscopy and genetic testing for FAP.

Pancreatoblastoma (PB) is a rare malignant pancreatic epithelial tumor that mostly occurs in children and occasionally occurs in adults. The tumor has acinar cell differentiation and squamous corpuscles/squamous epithelial islands, which are frequently separated by fibrous bundles. Familial adenomatous polyposis (FAP) is an autosomal dominant inherited disease characterized by the presence of numerous adenomatous polyps in the colon and rectum. Cases of pancreatoblastoma combined with familial adenomatous polyposis (FAP) are rarely reported. A review of a rare case of adult pancreatoblastoma with atypical histological morphology combined with familial adenomatous polyposis is presented herein. In this case, the patient was first diagnosed with familial adenomatous polyposis and subsequently found to have pancreatoblastoma 1 year and 3 months later. This suggests pancreatoblastoma may occur in patients with familial adenomatous polyposis or a family history of the condition, indicating a possible association between the two tumors. Therefore, pancreatoblastoma should be included in a differential diagnosis for FAP patients with a pancreatic mass. The final diagnosis of pancreatoblastoma depends on the pathological diagnosis. Acinar-like cells and squamous corpuscles/squamous epithelial cell islands under light microscopy are the key diagnostic points. This case report also can improve the awareness of clinicians, radiologists, and pathologists on the presence of rare tumor-adult pancreatoblastoma in patients with familial adenomatous polyposis.

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.

Adult pancreatoblastoma (PBL) is a rare pancreatic malignancy, with recent evidence suggesting a possible link to familial adenomatous polyposis (FAP). This study aims to review the latest evidence and explore a possible association between adult PBL and FAP.
Two independent literature reviews were conducted: (1) on PBL and FAP, and (2) on PBL in the adult population not diagnosed with FAP.
Out of 26 articles on PBL and FAP screened, 5 were selected for systematic review, including 1 additional case. We identified eight FAP-related PBL cases, with a median age of 40 (IQR: 34-50). Of these, seven (87%) occurred in adults. We found 65 cases of adult PBL not FAP-related; thus, 7 out of 65 cases (10.7%) of adult PBL reported in the literature are associated with a clinical diagnosis of FAP or were carriers of APC germline pathogenic variants (GPVs).
Data suggest a non-random association between adult PBL and FAP. Further research is essential to optimise surveillance protocols and develop more effective treatment strategies.

Genetic testing of the APC gene by sequencing analysis and MLPA is available across commercial laboratories for the definitive genetic diagnosis of familial adenomatous polyposis (FAP). However, some genetic alterations are difficult to detect using conventional analyses. Here, we report a case of a complex genomic APC-TP63 rearrangement, which was identified in a patient with FAP by a series of genomic analyses, including multigene panel testing, chromosomal analyses, and long-read sequencing. A woman in her thirties was diagnosed with FAP due to multiple polyps in her colon and underwent total colectomy. Subsequent examination revealed fundic gland polyposis. No family history suggesting FAP was noted except for a first-degree relative with desmoid fibromatosis. The conventional APC gene testing was performed by her former doctor, but no pathogenic variant was detected, except for 2 variants of unknown significance. The patient was referred to our hospital for further genetic analysis. After obtaining informed consent in genetic counseling, we conducted a multigene panel analysis. As insertion of a part of the TP63 sequence was detected within exon16 of APC, further analyses, including chromosomal analysis and long-read sequencing, were performed and a complex translocation between chromosomes 3 and 5 containing several breakpoints in TP63 and APC was identified. No phenotype associated with TP63 pathogenic variants, such as split-hand/foot malformation (SHFM) or ectrodactyly, ectodermal dysplasia, or cleft lip/palate syndrome (EEC) was identified in the patient or her relatives. Multimodal genomic analyses should be considered in cases where no pathogenic germline variants are detected by conventional genetic testing despite an evident medical or family history of hereditary cancer syndromes.

Desmoid fibromatosis (DF) is a clonal proliferative disorder of myofibroblasts, which arises, with a low incidence, in soft tissue, including within the abdomen. The incidence of DF is associated with familial adenomatous polyposis (FAP), and is more common following FAP surgery. It is rare for a patient to make his/her first visit to hospital due to DF symptoms associated with FAP. In the present report, a case of mesenteric DF associated with FAP is described. This case also had incomplete intestinal obstruction due to DF. By summarizing previous studies examining DF and FAP treatment, combined with the disease characteristics of this patient, the clinical treatment strategy for DF associated with FAP was explored.

Familial adenomatous polyposis (FAP) is characterized by hundreds of colonic adenomatous polyps and extraintestinal manifestations beginning in adolescence and early adulthood. It is also one of the most common hereditary colorectal cancer syndromes. In this case study, a rare phenotype of FAP associated with diffuse gastric polyposis, colon oligo-polyposis, and a massive retroperitoneal mass is described. The results expand on the current body of knowledge of FAP and may represent a new phenotypic expression of FAP. Accurate evidence-based surveillance and management recommendations for this disease require further research and evaluation.

Hepatocellular adenoma is a benign liver tumor often diagnosed incidentally in women of reproductive age who are taking oral contraceptives. In this study, we present a unique case of an 18-year-old man with known familial adenomatous polyposis who presented with sepsis in the setting of a recent total proctocolectomy and was incidentally found to have multiple large hepatic lesions. A biopsy of a liver lesion confirmed the diagnosis of a beta-catenin-activated hepatic adenoma. To the best of our knowledge, this is the first known case of beta-catenin-activated hepatic adenoma in a patient with a known familial adenomatous polyposis mutation. Beta-catenin is one of the many subtypes of hepatocellular adenomas, which carries a high risk of malignant transformation.