Tiger-Striped PASH: Recognition of a Unique Morphology Allows for a Zippered-Up Diagnosis of Pseudoangiomatous Stromal Hyperplasia of Breast

Pseudoangiomatous stromal hyperplasia (PASH) of the breast is histologically characterized by anastomosing and slit-like spaces invested by collagenous stroma and lined by flattened, spindle cells. These clear spaces that may mimic microscopic vascular channels do not contain red blood cells. Immunohistochemistry (IHC) studies may also help to confirm a diagnosis of PASH, with the spindled cells marking positively with CD34 and PR while demonstrating no reactivity with more specific endothelial antigens such as CD31 and ERG. In the current case, a 39-year-old female was diagnosed with cellular PASH of the right breast with unique histological patterns showing “tiger-striped” and “zippered” histologies. To our knowledge, this is the first report of these unique variant PASH morphologies.

Pseudoangiomatous stromal hyperplasia of thebreast: a rare condition – from diagnosis to treatment

Pseudoangiomatous Stromal Hyperplasia (PASH) of the breast is a rare condition that consists of the proliferation of the breast myofibroblastic stromal cells, lining anastomosing vascular slit-like spaces. This condition is not considered a pre-malignant lesion and affects mainly premenopausal women. Its etiology is still uncertain, but its behavior points to a hormonal cause. It has a varied clinical presentation and can be diagnosed as an incidental finding of biopsies or with the manifestation of clinical signs and symptoms. As for the diagnosis, it can be performed with the correlation between clinical data, imaging and histopathological analysis. Due to its rare nature, there are still no prospective studies regarding treatment, but, in most cases, clinical and radiological follow-up is a safe strategy. The aim of this paper is to synthesize the data available in the literature about this condition, which, although benign in nature, can bring important aesthetic, musculoskeletal and psychological repercussions.