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Key Diagnostic Strategies

desmoid tumor tendril

Approximately 30% to 40% of desmoid tumors are initially misdiagnosed, due to their rarity and histologic mimics.1 These challenges may result in delayed diagnosis or uncertainty around treatment approaches.2,3

A Multidisciplinary Approach Is Key and Recommended by Guidelines

A multidisciplinary approach to evaluation and management of disease can help support more accurate patient assessment, the prompt initiation of treatment, and individualized management of symptoms. Ultimately, this may improve prognoses and patients’ quality of life.2,3

NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines®) and the Desmoid Tumor Working Group recommend an initial evaluation and management by a multidisciplinary team with expertise and experience in sarcoma.4,5

A multidisciplinary team may include:

Multidisciplinary
care team

  • Medical oncologist
  • Sarcoma specialist
  • Surgeon/surgical oncologist
  • Radiologist and/or radiation oncologist
  • Primary care physician
  • Pathologist
  • Nurses
  • Mental health professional

Leveraging Diagnostic Tools for Timely and Accurate Diagnosis

Evaluation for suspected desmoid tumors should include imaging4 (performed with contrast unless contraindicated) and histopathologic assessment of biopsy tissue.6 Genetic testing for CTNNB1 and APC mutations can help distinguish between sporadic desmoid tumors (85%-90%) and those arising in the context of familial adenomatous polyposis (FAP, 10%-15%).5,7

Typically in both contexts, the protein beta-catenin accumulates in the cell nucleus, leading to overexpression of key target genes that drive desmoid tumor pathogenesis.7

NCCN Guidelines® recommend the following prior to determining any specific therapeutic interventions (surgery or systemic therapy) for progressive, morbid, or symptomatic disease:4

  • CT/MRI scan
  • Core biopsy

The Desmoid Tumor Working Group consensus guideline recommends:5

  • Genetic testing for CTNNB1 or APC mutations

Diagnostic Tools

Imaging

MRI of the abdominal wall and extra-abdominal desmoid tumors is typically recommended for initial diagnosis and postsurgical recurrence. A CT scan (with contrast) is often recommended for diagnosing intra-abdominal desmoid tumors and can be used to evaluate changes in tumor size.4-6 See desmoid tumor images

Core Needle Biopsy and Nuclear Beta-Catenin Staining

Histopathologic assessment and immunostaining for beta-catenin are important for diagnosis of desmoid tumors.8 The Desmoid Tumor Working Group identifies nuclear positivity for beta-catenin as the key immunophentoypic feature of desmoid tumors.6 See staining

The presence of nuclear immunopositivity for beta-catenin has been reported in 80% to 98% of sporadic desmoid tumor cases and 60% to 100% of FAP-associated desmoid tumor cases.6

Genetic Testing

Most sporadic desmoid tumors are associated with activating mutations of the beta-catenin gene (CTNNB1). Familial desmoid tumors are associated with germline inactivating APC mutations in the context of FAP. Genetic testing can help distinguish between these 2 etiologies.5

Radiology & Pathology of Desmoid Tumors

Approximately 30%-40% of desmoid tumors are initially misdiagnosed.1

Learn more about what the guidelines recommend to help provide a timely, accurate diagnosis for your patients.

Imaging

Despite being infiltrative, many desmoid tumors may appear well-circumscribed, or entrapped and atrophied muscle may be mistaken for malignancy.9


CT is preferable for intra-abdominal desmoid tumors and associated complications9

CT scan of a desmoid tumor
Image reproduced with permission from Shinagare AB, Ramaiya NH, Jagannathan JP, et al. A to Z of desmoid tumors. AJR Am J Roentgenol. 2011;197(6):W1008-W1014.

Contrast-enhanced CT showed a large unresectable mesenteric desmoid tumor (arrowheads) closely associated with mesenteric vessels (arrow)10

The tumor was originally identified during pregnancy and suspected to be an ovarian mass prior to biopsy10

MRI can provide clues to histology and progression risk9,11

Hyperintense T2 signal is associated with high cellularity and increased risk of desmoid tumor progression9,11

MRI scan of a desmoid tumor
Image reproduced with permission from Xu H, Koo HJ, Lim S, et al. Desmoid-type fibromatosis of the thorax: CT, MRI, and FDG PET characteristics in a large series from a tertiary referral center. Medicine (Baltimore). 2015;94(38):e1547.

T2-weighted MRI scan showed hyperintensity and ill-defined margins (white arrows) of a progressing axilla desmoid tumor12

This tumor was initially misdiagnosed as a sarcoma on preoperative CT but correctly diagnosed by MRI12

Core Needle Biopsy and Nuclear Beta-Catenin Staining

The heterogeneous morphology of desmoid tumors can make diagnosis challenging13

  • On average, desmoid tumors have 2 distinct histologic patterns, but some may demonstrate up to 5 patterns, with intra-abdominal tumors having the greatest variability13
  • The 3 most common histologic patterns, any of which may be observed in a single tumor, are shown below:13
Conventional histologic pattern
Image reproduced with permission from Zreik RT, Fritchie KJ. Morphologic spectrum of desmoid-type fibromatosis. Am J Clin Pathol. 2016;145(3):332-340.

Conventional
100% of cases—sweeping fascicles of uniform spindle fibroblasts with little cell-to-cell contact, abundant collagen and blood vessels13
Mitoses and atypia are rarely seen13,14

Hypocellular/hyalinized histologic pattern
Image reproduced with permission from Zreik RT, Fritchie KJ. Morphologic spectrum of desmoid-type fibromatosis. Am J Clin Pathol. 2016;145(3):332-340.

Hypocellular/hyalinized
28% of cases—decreased cellular density and increased stromal hyalinization13

Although fibroblasts are still present, they are typically widely spaced and set in a densely eosinophilic matrix13

Staghorn vessel histologic pattern
Image reproduced with permission from Zreik RT, Fritchie KJ. Morphologic spectrum of desmoid-type fibromatosis. Am J Clin Pathol. 2016;145(3):332-340.

Staghorn Vessel
21% of cases—thin-walled branched blood vessels lined by a single layer of flat to ovoid endothelial cells that appear hyperchromatic relative to the lighter staining stromal cells13

In addition to heterogeneous morphology, accurate diagnosis is also complicated due to histologic mimics1

Low-grade sarcomas, GIST, nodular fasciitis, and other histologic mimics can often be differentiated from desmoid tumors through a combination of histologic findings and ancillary testing, with examples below:13,15,16

Fibromyxoid sarcoma with focal nuclear atypia
Image reproduced with permission from Li M, Chen H, Shi D, Chen M, Zhang Z, Zhang H. Low-grade fibromyxoid sarcoma: a clinicopathologic and molecular study of 10 genetically confirmed cases. Int J Clin Exp Pathol. 2018;11(12):5860-5868.

Low-grade fibromyxoid sarcoma with focal nuclear atypia that is rare in desmoid tumors13,17

Absence of nuclear beta-catenin staining and positivity for MUC4 by immunohistochemistry, and FUS gene rearrangements, can help distinguish low-grade fibromyxoid sarcomas from desmoid tumors13,18

Desmoid tumor with nuclear beta-catenin staining
Image reproduced with permission Kasper B, Baumgarten C, Garcia J, et al. An update on the management of sporadic desmoid-type fibromatosis: a European Consensus Initiative between Sarcoma PAtients EuroNet (SPAEN) and European Organization for Research and Treatment of Cancer (EORTC)/Soft Tissue and Bone Sarcoma Group (STBSG). Ann Oncol. 2017;28(10):2399-2408. Reused under Creative Commons License CC BY-NC 4.0. https://creativecommons.org/licenses/by-nc/4.0/

Desmoid tumor with characteristic nuclear beta-catenin staining1

Presence of CTNNB1 or APC mutations can help confirm a desmoid tumor diagnosis13,15

GIST with DOG1 staining
Image reproduced with permission from PathologyOutlines.com. Small intestine & ampulla; other malignancies; GIST. Accessed October 25, 2022. https://www.pathologyoutlines.com/topic/smallbowelGIST.html.

GIST with diffuse DOG1 staining that is not observed in desmoid tumors19,20

Absence of nuclear beta-catenin and positivity for CD117 (c-kit) can help distinguish GIST from desmoid tumors13,15

alt="Nodular fasciitis with USP6 gene rearrangement"
Image reproduced with permission from Emori M, Shimizu J, Murahashi Y, et al. Nodular fasciitis involving the palm. Ann R Coll Surg Engl. 2018;100(5):e128-e131.

Nodular fasciitis with USP6 gene rearrangement by FISH (separation of red and green dots)21

A high mitotic index and absence of nuclear beta-catenin can help distinguish nodular fasciitis from desmoid tumors13,16,18

Next: Management

CT, computed tomography; FDA, Food and Drug Administration; FISH, fluorescence in situ hybridization; GIST, gastrointestinal stromal tumor; IV, intravenous; MRI, magnetic resonance imaging; NCCN, National Comprehensive Cancer Network® (NCCN®).

SpringWorks is providing this link to assist patients in finding a specialist by region, but had no role in developing the list and inclusion does not represent an endorsement or a recommendation from SpringWorks for any center or physician.

  1. Kasper B, Baumgarten C, Garcia J, et al. Desmoid Working Group. An update on the management of sporadic desmoid-type fibromatosis: a European Consensus Initiative between Sarcoma PAtients EuroNet (SPAEN) and European Organization for Research and Treatment of Cancer (EORTC)/Soft Tissue and Bone Sarcoma Group (STBSG). Ann Oncol. 2017;28(10):2399-2408.
  2. Husson O, Younger E, Dunlop A, et al. Desmoid fibromatosis through the patients’ eyes: time to change the focus and organisation of care? Support Care Cancer. 2019;27(3):965-980.
  3. Joglekar SB, Rose PS, Sim F, Okuno S, Petersen I. Current perspectives on desmoid tumors: the Mayo Clinic approach. Cancers (Basel). 2011;3(3):3143-3155.
  4. Referenced with permission from the NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines®) for Soft Tissue Sarcoma V.2.2022. © National Comprehensive Cancer Network, Inc. 2022. All rights reserved. Accessed May 23, 2022. To view the most recent and complete version of the guideline, go online to NCCN.org. NCCN makes no warranties of any kind whatsoever regarding their content, use or application and disclaims any responsibility for their application or use in any way.
  5. Gronchi A, et al. Desmoid Tumor Working Group. The management of desmoid tumours: a joint global consensus-based guideline approach for adult and paediatric patients. Eur J Cancer. 2020;127:96-107.
  6. Gronchi A, et al. Desmoid Tumor Working Group. The management of desmoid tumours: a joint global consensus-based guideline approach for adult and paediatric patients [supplementary appendix]. Eur J Cancer. 2020;127:96-107.
  7. Penel N, Chibon F, Salas S. Adult desmoid tumors: biology, management and ongoing trials. Curr Opin Oncol. 2017;29(4):268-274.
  8. Carlson JW, Fletcher CDM. Immunohistochemistry for β-catenin in the differential diagnosis of spindle cell lesions: analysis of a series and review of the literature. Histopathology. 2007;51(4):509-514.
  9. Rosa F, Martinetti C, Piscopo F, et al. Multimodality imaging features of desmoid tumors: a head-to-toe spectrum. Insights Imaging. 2020;11(1):103.
  10. Shinagare AB, Ramaiya NH, Jagannathan JP, et al. A to Z of desmoid tumors. AJR Am J Roentgenol. 2011;197(6):W1008-W1014.
  11. Cassidy MR, Lefkowitz RA, Long N, et al. Association of MRI T2 signal intensity with desmoid tumor progression during active observation: a retrospective cohort study. Ann Surg. 2020;271(4):748-755.
  12. Xu H, Koo HJ, Lim S, et al. Desmoid-type fibromatosis of the thorax: CT, MRI, and FDG PET characteristics in a large series from a tertiary referral center. Medicine (Baltimore). 2015;94(38):e1547.
  13. Zreik RT, Fritchie KJ. Morphologic spectrum of desmoid-type fibromatosis. Am J Clin Pathol. 2016;145(3):332-340.
  14. Soft Tissues: Desmoid-type fibromatosis. Atlas of Genetics and Cytogenetics in Oncology and Haematology website. Written 2013. Accessed October 25, 2022. https://atlasgeneticsoncology.org/solid-tumor/5179/soft-tissues-desmoid-type-fibromatosis.
  15. Huss S, Nehles J, Binot E, et al. β-catenin (CTNNB1) mutations and clinicopathological features of mesenteric desmoid-type fibromatosis. Histopathology. 2013;62(2):294-304.
  16. Sbaraglia M, Bellan E, Dei Tos AP. The 2020 WHO Classification of Soft Tissue Tumours: news and perspectives. Pathologica. 2021;113(2):70-84.
  17. Li M, Chen H, Shi D, Chen M, Zhang Z, Zhang H. Low-grade fibromyxoid sarcoma: a clinicopathologic and molecular study of 10 genetically confirmed cases. Int J Clin Exp Pathol. 2018;11(12):5860-5868.
  18. Bhattacharya B, Dilworth HP, Iacobuzio-Donahue C, et al. Nuclear beta-catenin expression distinguishes deep fibromatosis from other benign and malignant fibroblastic and myofibroblastic lesions. Am J Surg Pathol. 2005;29(5):653-659.
  19. PathologyOutlines.com. Small intestine & ampulla; other malignancies; GIST. Accessed October 25, 2022. https://www.pathologyoutlines.com/topic/smallbowelGIST.html.
  20. West RB, Corless CL, Chen X, et al. The novel marker, DOG1, is expressed ubiquitously in gastrointestinal stromal tumors irrespective of KIT or PDGFRA mutation status. Am J Pathol. 2004;165(1):107-113.
  21. Emori M, Shimizu J, Murahashi Y, et al. Nodular fasciitis involving the palm. Ann R Coll Surg Engl. 2018;100(5):e128-e131.