Pseudoangiomatous stromal hyperplasia (PASH) is a benign proliferative lesion of mammarian stroma that presents as a localized mass. We describe the clinical, radiologic, cytologic, and histopathologic features of a case of PASH with giant cells that presented as a rapidly growing localized mass in the breast in a 32-year-old woman. An unusual feature of our case was the presence of multinucleated giant cells lining pseudovascular spaces and dispersing in collagenous stroma. To the best of our knowledge, this is the second case in the English literature and PASH with predominance of multinucleated giant cells has never been described previously in a female patient.