To Worry or Not: A Case of Nodular Pseudoangiomatous Stromal Hyperplasia of the Breast and a Review of the Literature.

Pseudoangiomatous stromal hyperplasia (PASH) is a benign mesenchymal proliferative breast lesion. It is very unusual for PASH to form a nodule on its own, in the absence of other breast lesions, an entity called "nodular PASH." Given its rarity, we present an interesting case of this poorly understood breast pathology in a 25-year-old lady who was initially diagnosed with fibroadenoma of the left breast. Breast ultrasound and mammography are the most frequently used techniques to assess breast pathologies. Fibroadenomas can clinically and radiologically mimic the appearance of nodular PASH. Therefore, due to the non-specific features of nodular PASH, histologic examination remains the gold standard for confirming this rare diagnosis and ruling out low-grade angiosarcoma. Patients with nodular PASH have an excellent prognosis after excision. PASH is a benign stromal proliferation that histologically stimulates a vascular lesion; reporting additional cases is essential to develop comprehensive guidelines for its management.