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PASH mastopathy refers to a diffuse and exaggerated form of Pseudoangiomatous stromal hyperplasia (PASH), presenting as massive, often bilateral breast enlargement, usually in adolescents or young women.
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It represents the extreme end of the PASH spectrum, mimicking gigantomastia (galactomastia) but with a characteristic histologic appearance.
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PASH mastopathy is a rare, hormonally sensitive, benign condition involving:
Diffuse stromal proliferation
Histologic features of PASH: dense collagenous stroma with pseudoangiomatous slit-like spaces </aside>
Believed to be a hormone-driven proliferation of breast stromal myofibroblasts
Progesterone sensitivity is most strongly implicated
Often seen in:
| Feature | Description |
|---|---|
| Breast enlargement | Diffuse, massive, and often rapid |
| Laterality | Bilateral, though can be asymmetric |
| Palpable nodularity | Diffuse firmness or “lumpy” texture throughout the breast |
| Skin tension | May cause discomfort, back pain, or postural issues |
| Psychosocial distress | Especially in adolescents |
Bilateral galactomastia and histological examination in a patient with pseudoangiomatous stromal hyperplasia. (a) Bilateral galactomastia. After bilateral mastectomy, (b) the right breast specimen weighed 5275 g and (c) the left breast specimen weighed 6493 g. (d) Histological examination of the tissue revealed stromal hyperplasia and slit-like spaces (marked with arrows) lined by endothelial-like spindle cells.
Lian Z, Chen X, Liu C. Pseudoangiomatous stromal hyperplasia causing bilateral galactomastia with short-term recurrence after surgery: a case report. Journal of International Medical Research. 2024;52(11). doi:10.1177/03000605241293684
| Modality | Imaging features |
|---|---|
| US | • Diffuse heterogeneous parenchyma: Often hyperechoic or mixed echotexture |
| • No discrete mass: Widespread stromal proliferation | |
| • No suspicious vascularity: No solid mass or nodular enhancement | |
| Mammography | Findings are nonspecific |
| • Very dense breast tissue: May obscure assessment in large breasts | |
| • No focal mass or calcification | |
| MR | Preoperative planning or exclusion of hidden malignancy |
| • Diffuse homogeneous enhancement; no suspicious focal lesions |
Mammography findings in a patient with pseudoangiomatous stromal hyperplasia. Mammography of the (a) right breast and (b) left breast showed diffuse enlargement without clear calcifications, and multiple masses appeared to be present.
Lian Z, Chen X, Liu C. Pseudoangiomatous stromal hyperplasia causing bilateral galactomastia with short-term recurrence after surgery: a case report. Journal of International Medical Research. 2024;52(11). doi:10.1177/03000605241293684