# Gardner syndrome initially misdiagnosed as bilateral breast malignancy: a case report and literature review

## TL;DR

A 27-year-old woman with Gardner syndrome was initially misdiagnosed with breast cancer, highlighting the need for multidisciplinary evaluation in rare genetic disorders.

## Contribution

This case highlights the atypical breast presentation of Gardner syndrome and the importance of systematic multidisciplinary diagnosis.

## Key findings

- Bilateral breast fibromatosis mimicked invasive breast carcinoma in imaging and histopathology.
- Systemic evaluation revealed craniofacial osteomas, soft tissue tumors, and colorectal polyps consistent with Gardner syndrome.
- Multidisciplinary collaboration was essential for accurate diagnosis and management of this rare hereditary condition.

## Abstract

To report a rare case of Gardner syndrome (GS) initially presenting with bilateral breast masses, emphasizing the diagnostic challenges of atypical manifestations and the importance of multidisciplinary collaboration.

A retrospective analysis was conducted using clinical data, multimodal imaging (ultrasound, mammography, magnetic resonance imaging, and computed tomography), histopathological evaluation via core needle biopsy, and multidisciplinary team (MDT) consultation. Colonoscopy was performed to confirm systemic involvement.

A 27-year-old woman presented with bilateral breast masses that were initially suspected to be malignant. Imaging revealed irregular spiculated lesions mimicking invasive carcinoma. Histopathological examination confirmed the presence of fibromatosis in both breasts and the right interpectoral region. Systemic evaluation revealed craniofacial osteomas, subcutaneous/muscular soft tissue tumors, left adrenal adenoma, and multiple colorectal polyps (superficial serrated adenomas). MDT review confirmed GS based on intestinal polyposis, osteomas, soft-tissue tumors, and histopathological criteria.

This case underscores the critical role of multimodal imaging, histopathology, and MDT collaboration in clinical diagnosing GS with rare breast involvement. A systematic evaluation of extracolonic manifestations (e.g., adrenal adenomas) and the recognition of fibromatosis mimicking malignancy are essential for early diagnosis. Genetic evaluation and interdisciplinary management optimize the outcomes of complex hereditary syndromes.