Pseudomyxoma Peritonei
Pseudomyxoma Peritonei - StatPearls - NCBI Bookshelf
- mucinous abdominal cancer: “jelly belly”
- Risk factors: familial adenomatous polyposis
- omental cake
Peritoneal Carcinomatosis
Abdominal Compartment Syndrome
Acute Mesenteric Ischemia
Portal Vein Thrombosis
Pneumatosis Intestinalis
Pneumobilia
- Bad bad (normally, air in abd = perf or infection)
- Normal in RNYHJ (Roux en Y Hepaticojejunostomy) d/t new anatomy
Desmoid Tumors and FAP
Quick Reference
| Topic | Summary |
| Condition | Desmoid tumors in Familial Adenomatous Polyposis (FAP) |
| Key Association | ~10–15% of FAP patients develop desmoid tumors |
| Location | Primarily intra-abdominal (mesenteric, retroperitoneal, abdominal wall) |
| Behavior | Locally aggressive, non-metastatic |
| Risk Factors | Family history of desmoids, extracolonic manifestations, certain APC genotypes |
| Management Strategy | Multidisciplinary; non-surgical treatments preferred first-line |
| Preferred Initial Treatment | Medical: NSAIDs, anti-estrogens, TKIs (e.g., sorafenib), low-dose chemo, observation |
| Surgical Indications | 2nd line: Easily resectable abdominal wall desmoids or complications unresponsive to medical therapy |
Pathophysiology
- APC Mutations in FAP lead to dysregulated Wnt/β-catenin signaling, predisposing to both colorectal adenomas and intra-abdominal desmoid tumors.
- Desmoid tumors are fibroblastic proliferations that are locally invasive but lack metastatic potential.
- In sporadic desmoids, CTNNB1 (β-catenin) mutations drive tumorigenesis via the same Wnt pathway, and are mutually exclusive with APC mutations.
- Desmoid formation is often triggered by surgical trauma, especially post-colectomy in FAP patients.
Epidemiology
- FAP prevalence: ~1 in 8,000–10,000 individuals.
- Desmoid tumors in FAP: Occur in 10–15% of patients, often at a younger age than sporadic cases.
- Sporadic desmoid tumors: Rare, more often extra-abdominal, associated with CTNNB1 mutations.
- Desmoid-related mortality in FAP: Accounts for up to 21% of deaths.
- Additional APC-related conditions: Include gastric polyposis, duodenal polyps, hepatoblastoma, medulloblastoma (Turcot syndrome), and thyroid/adrenal tumors.
Diagnosis
- Presentation: May be asymptomatic or cause pain, bowel obstruction, or organ compromise due to local invasion.
- Timing: Frequently post-operative (e.g., post-colectomy in FAP).
- Location clues: FAP-associated = intra-abdominal; Sporadic = often extra-abdominal.
- Genetic Testing: APC mutation analysis in FAP; CTNNB1 genotyping for sporadic desmoids.
Treatment
General Approach
- Managed at specialized centers using a multidisciplinary strategy.
- Observation is appropriate for stable, asymptomatic tumors
Medical Therapy (Preferred First-line for Intra-abdominal Desmoids)
- NSAIDs
- Anti-estrogens
- Tyrosine kinase inhibitors (TKIs): e.g., sorafenib, imatinib
- Low-dose chemotherapy: methotrexate/vinblastine or anthracycline regimens
- Emerging agents: γ-secretase inhibitors (e.g., nirogacestat)
Surgery - Reserved for:
- Abdominal wall desmoids that are easily resectable
- Intra-abdominal tumors with intractable symptoms or complications unresponsive to medical therapy
References
- Poylin VY, Shaffer VO, Felder SI, et al. Diseases of the Colon and Rectum. 2024;67(2):213–227. doi:10.1097/DCR.0000000000003072
- Aoun RJN, Kalady MF. Familial Cancer. 2025;24(3):56. doi:10.1007/s10689-025-00481-9
- DE Marchis ML, Tonelli F, Quaresmini D, et al. Anticancer Res. 2017;37(7):3357–3366. doi:10.21873/anticanres.11702
- Al-Sukhni E, Shapiro J, Suraweera H, et al. Ann Surg Oncol. 2023;30(8):5142–5149. doi:10.1245/s10434-023-13675-1
- Kasper B, Baldini EH, Bonvalot S, et al. JAMA Oncol. 2024;10(8):1121–1128. doi:10.1001/jamaoncol.2024.1805
- Desurmont T, Lefèvre JH, Shields C, et al. Familial Cancer. 2015;14(1):31–9. doi:10.1007/s10689-014-9760-1
- Gounder MM, Mahoney MR, Van Tine BA, et al. N Engl J Med. 2018;379(25):2417–2428. doi:10.1056/NEJMoa1805052
- Riedel RF, Agulnik M. Cancer. 2022;128(16):3027–3040. doi:10.1002/cncr.34332
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