Pseudoangiomatous stromal hyperplasia: A clinical perspective and a brief review.

Pseudoangiomatous stromal hyperplasia (PASH) is a benign entity of the breast and typically found incidentally or as a palpable mass. It usually affects women in the reproductive age group. In men, it is associated with gynecomastia. While the exact etiology is unknown, PASH is considered hormonally responsive. The mammography and ultrasonography findings are nonspecific. Grossly, PASH is a well-circumscribed, firm, rubbery mass with solid, homogenous, gray-white cut surface. On histologic examination, it is characterized by the presence of open slit-like spaces in dense collagenous stroma. The spindle cells express progesterone receptors and are positive for vimentin, actin, and CD34. PASH lesions should be surgically excised if increasing in size or associated with symptoms, also in cases of suspicious imaging findings or other lesions are synchronously diagnosed that require excision. In other small incidentally detected asymptomatic cases observation with clinicoradiological follow-up can be considered. It is associated with a good prognosis with no increased risk to develop breast cancer. Hence, the operating surgeon and pathologist should be aware of this not so uncommon entity so that patients are not subjected to unnecessary excision and subsequent physical and mental morbidity associated with it. In this article, we present a case report and also provide a brief review of the sparse literature on PASH, discussing clinical presentation, etiology and pathogenesis, radiopathological features, differential diagnosis, and the implications for further patient management and prognosis.