Tumorous PASH presenting as rapid unilateral breast enlargement.

36-year-old woman presented with a 3-month history of progressive, rapid enlargement of the right breast. She had no family history of breast diseases and had not been taking any medications. On examination, the right breast was dramatically enlarged when compared with the left (Figure 1). We obtained a bilateral diagnostic mammogram, ultrasonography, core biopsies (Figure 2 ,A ), and magnetic resonance imaging (Figure 2 ,B ) of the right breast. Pathologic examination revealed pseudoangiomatous stromal hyperplasia (PASH), with no evidence of malignancy. The patient underwent a bilateral mastectomy with immediate breast reconstruction, and the tumor resected from the right breast measured 11.0 8.5 6.0 cm and weighed 666.0 g. The final pathologic findings were consistentwithtumorousPASH. 1 Thisisamong thelargestPASHtumorsreportedinthemedical literature. The patient had an excellent clinical and cosmetic outcome. An incidental finding of microscopic PASH