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The mass was extirpated by a round block incision, although the nipple-areola complex had a large diameter (7 cm), and a vertical prolongation had to be done to allow the extraction of the giant tumor (13 cm × 14 cm; 740 g). Pathologic examination revealed a breast hamartoma.

Breast hamartomas are uncommon benign lesions. They are well-circumscribed tumors composed of a variable mixture of epithelial elements, fat, and fibrous tissue.¹ As it did in our case, a hamartoma may appear as a homogeneously dense, well-circumscribed mass, which can vary in appearance from a classically described mass to an encapsulated, mixed, fatty-fibroglandular mass.² The role of fine-needle aspiration cytology and core-needle biopsy in making the diagnosis is limited and requires clinical and radiologic correlation to avoid underdiagnosis. In our case, the histologic diagnosis by core-needle biopsy was pseudoangiomatous stromal hyperplasia; this histologic feature needs to be distinguished from another benign and malignant lesion, which sometimes has a similar cytologic apperance.³ The incidence rate of pseudoangiomatous stromal hyperplasia in hamartomas ranges from a high incidence of 71%⁴ to a low incidence of 16%.⁵ Hamartomas with associated pseudoangiomatous stromal hyperplasia may show marked vascularity; this was clearly demonstrated in magnetic resonance imaging.^4,6 Magnetic resonance imaging of the breast hamartoma revealed a tumor with intermediate signal intensity on both T1- and T2-weighted images, and showed a time-signal intensity curve with a slow and progressive enhancement; dynamic contrast enhancement suggested a benign lesion.⁷ Usually hamartomas are described as slow-growing lesions; in our case, the mass doubled its size in 10 months. In this situation we had to make a differential diagnosis of a malignant mass; other possible diagnoses included a circumscribed fibrocystic lesion, fibroadenoma, and cystosarcoma phyllodes. The size and weight of the tumor in our case led us to determine it was a giant hamartoma.⁸ Three months after the removal of the tumor the healthy breast tissue expanded and the breast recovered its usual appearance.

Correspondence: Pilar Alonso-Bartolomé, MD, Radiology Division, Hospital Universitario Marqués de Valdecilla, Avenida Valdecilla, Santander, Spain 39008 (mpalonso@humv.es).

Accepted for Publication: January 31, 2006.

Author Contributions:Study concept and design: Hernanz, Alonso-Bartolomé, Garijo, Vega, Alvarez, and Gómez-Fleitas. Acquisition of data: Hernanz, Alonso-Bartolomé, and Ortega. Analysis and interpretation of data: Hernanz, Alonso-Bartolomé, and Ortega. Drafting of the manuscript: Hernanz and Alonso-Bartolomé. Critical revision of the manuscript for important intellectual content: Hernanz, Alonso-Bartolomé, Garijo, Vega, Ortega, Alvarez, and Gómez-Fleitas. Administrative, technical, and material support: Hernanz, Alonso-Bartolomé, Garijo, Vega, Ortega, and Alvarez. Study supervision: Gómez-Fleitas.

Financial Disclosure: None reported.