Desmoid-Type Fibromatosis of the Breast Mimicking Carcinoma in a 26-Year-Old Female: A Case Report and Discussion of Β-Catenin Negative Diagnostic Challenges

Badria Aljohani, Fatima Ali, Entisar Mohieldeen, Ayman Ali and Malik Alrashedi

King Salman bin Abdulaziz Medical City, KSA Breast Center, Sudan National University, Sudan King Salman bin Abdulaziz Medical City, Histopathological Department, Sudan

^*Correspondance to: Fatima Ali 

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Abstract:

Desmoid-Type Fibromatosis (DTF) is a rare, non-metastasizing, but locally aggressive soft tissue tumor developing from monoclonal myofibroblast growth. It is generally connected to mutations in the CTNNB1 gene (encoding β-catenin) or, less commonly, the APC gene in Familial Adenomatous Polyposis (FAP) patients. While lacking metastatic potential, DTF produces severe morbidity due to infiltrative development, high recurrence rates, and an unpredictable clinical outcome that might include spontaneous remission or chronic progression. It most usually affects young adults (peak age 30-40), with a slight female predominance, and can arise in practically any anatomical place, albeit it is unusual in the breast. We report a case of a 26-year-old Saudi female who came with a solid, painless lump in the left inframammary fold. Initial imaging and core biopsy were inconclusive. Although immunohistochemistry was negative for nuclear β-catenin, a subsequent excisional biopsy confirmed the diagnosis based on conventional morphological characteristics and a low proliferative index. We aimed to highlight the diagnostic challenges of β-catenin-negative breast fibromatosis through a case analysis supported by immunohistochemical and morphological evidence. This example underscores the diagnostic difficulties of breast DTF, particularly in β-catenin negative cases. It underlines the requirement of a multidisciplinary approach and complete histological examination to avoid misdiagnosis, overtreatment, and to minimize unnecessary invasive operations.

Keywords:

Desmoid-type fibromatosis; Breast; β-catenin negative; Diagnostic; Case report

Cite the Article:

Aljohani B, Ali F, Mohieldeen E, Ali A, Alrashedi M. Desmoid-Type Fibromatosis of the Breast Mimicking Carcinoma in a 26-Year-Old Female: A Case Report and Discussion of Β-Catenin Negative Diagnostic Challenges. Clin Oncol. 2025; 10: 2128..