Differential Diagnosis for a Breast Mass

Single most likely diagnosis

• Fibroadenoma: A common benign breast tumor, especially in young women, characterized by a firm, mobile, and palpable mass, which matches the description provided.

Other Likely diagnoses

• Cyst: A fluid-filled sac that can present as a firm, palpable mass, especially if it is near the surface and not fully filled with fluid, making it feel more solid.
• Lipoma: A benign tumor composed of fat tissue, which can be firm and mobile, although it is less common in the breast compared to other parts of the body.
• Hamartoma: A benign growth that can contain a mixture of glandular, fibrous, and fatty tissues, presenting as a firm, mobile mass.

Do Not Miss (ddxs that may not be likely, but would be deadly if missed)

• Breast Cancer: Although less likely given the description of the mass being mobile and having no overlying skin changes, breast cancer must always be considered, especially in older patients or those with risk factors. It's crucial to not miss this diagnosis due to its potential severity.
• Phyllodes Tumor: A rare tumor of the breast that can be benign, borderline, or malignant, presenting as a firm, mobile mass, but can grow quickly and have a potential for malignancy.

Rare diagnoses

• Pseudoangiomatous Stromal Hyperplasia (PASH): A rare benign condition that can mimic a tumor, presenting as a firm mass, but is less common and might not be initially considered without further diagnostic workup.
• Granular Cell Tumor: A rare tumor that can occur in the breast, usually benign, but can be mistaken for a malignant process due to its potential for local invasion and rare metastatic potential.