Abstract
We report a case of pseudoangiomatous stromal hyperplasia (PASH) of the breast. During a medical checkup 6 years ago, a 51-year-old woman was diagnosed with a mass in her left breast, which was suspected to be fibroadenoma according to the findings from the aspiration biopsy cytology ; she was recommended to undergo observation to monitor her progress. The patient visited our hospital because, as assessed by mammography, the mass continued to grow in size. A 23-mm movable mass was located in the A area of the left breast. Although mammography and ultrasonography revealed no malignant findings, we performed an excisional biopsy because the mass increased in size. The tumor was a solid, grayish-white, elastic-hard lesion measuring 35×24×15 mm. Pathological examination revealed a collection of glands in an increased amount of stroma. The stroma around the glands exhibited slit-like spaces lined with spindle cells. These stromal spindle cells were immunohistochemically positive for CD34 and vimentin and negative for Factor VIII, thus leading to the histopathological diagnosis of the lesions as PASH.
