1708
A mammary stromal tumor with myofibroblastic differentiation.
Pseudoangiomatous stromal hyperplasia (PASH) is frequently a microscopic incidental finding in breast biopsies performed for benign or malignant disease.
It may also produce a mass lesion.
The mass, typically unilateral, was usually diagnosed clinically as a fibroadenoma.
Most lesions have a well-circumscribed tumor with a firm white-gray cut surface.
Microscopically, there was a spectrum of pathological stromal changes.
The spindle cells present are vimentin and CD34 positive and factor VIII negative.
In more cellular fascicular lesions, the stromal cells acquired desmin and actin positivity.
Immunohistochemical features are consistent with myofibroblastic histogenesis of PASH.
Progesterone receptor (PR) activity typically exceeded estrogen receptor (ER) in the nuclei of stromal and glandular cells.
In most lesions, the nuclei of stromal spindle cells are ER negative.
The majority of patients are treated by excisional biopsy.
Myofibroblasts play a major role in the histogenesis of PASH, but the pathogenesis remains uncertain.
Ab2242ant reactivity of myofibroblasts to endogenous or exogenous hormones is likely to be important factors.
Simple excision is adequate treatment in most cases
Occasionally presents a difficult management problem that may necessitate mastectomy. Ready for site