Pseudoangiomatous stromal hyperplasia is a condition that affects the breast tissues, and may or may not be painful. It is benign but may cause masses that need to be removed in some cases.
Pseudoangiomatous stromal hyperplasia (PASH) is a benign (noncancerous) breast lesion. It can present as a dense mass that may or may not be felt when palpating the breast. No mass is present in some cases, but other tissue changes may signal the condition.
The breast mass in PASH is caused by an overgrowth of myofibroblastic cells. These are a cross between cells found in connective tissues and cells found in smooth muscles. While not very common, PASH may also manifest itself with severe breast enlargement.
Even when PASH does produce a palpable mass, it’s often painless. That’s why the condition is usually found incidentally, such as during a routine mammogram.
PASH can occur at any age, but it’s generally more likely to develop in women in premenopausal or perimenopausal years and men with hormonal imbalances that lead to gynecomastia (enlarged breast tissue).
PASH may manifest as a non-mass lesion. In most cases, when masses are present, these are microscopic and cause no symptoms. A doctor may find the mass during a diagnostic test for another condition, like a mammogram.
However, PASH can also present as a larger mass. When you feel a PASH mass in the breast, it’s usually firm and moveable.
Breast masses in PASH are typically firm, but move under the tissue. They can be palpable during a breast exam. In rare cases, PASH causes breasts to become larger and may cause more than one mass. Pain is usually not a symptom of PASH, but it is possible, especially in cases of breast enlargement.
In many cases, PASH is an incidental diagnosis. It often occurs during a routine mammogram or breast biopsy for another breast condition, like fibroadenoma. (Fibroadenoma is another type of painless breast lump that can be confused with PASH.)
Checking in with a doctor whenever a breast lump is palpable is highly advised. They may order additional imaging tests, like an ultrasound or MRI. They may also suggest you undergo a core needle biopsy.
This procedure is usually done using a local anesthetic to numb the area. A doctor inserts a hollow needle into the breast to remove tissue for sampling. The sample is then sent to a lab for evaluation and a definitive diagnosis.
The exact causes of PASH remain undetermined.
Experts suspect that hormonal influences, especially progesterone imbalances, may play a role since the condition is most likely to develop in women of premenopausal age and men with enlarged breast tissue.
Experts have also associated PASH with the use of hormonal birth control and hormone replacement therapy.
PASH is not cancer, and research has not indicated a connection between having PASH and developing breast cancer or malignancies. In other words, having PASH does not increase your chances of breast cancer.
PASH masses do not become cancerous, although they may sometimes co-exist with malignant growths.
A doctor may recommend monitoring PASH masses that are not causing symptoms. The masses do tend to grow over time, and regular follow-up (often with mammography) is advised.
Some people may prefer having the mass removed. This may be a good option if you have a family history of breast cancer, if the mass is large and causing symptoms, or if it’s just generally making you uneasy.
Removing a PASH mass can be done via a lumpectomy, a breast lump removal. The procedure is performed under general anesthesia, usually in an outpatient center, and doesn’t require removing surrounding tissue, as in a cancer removal surgery. Doctors may call this an excisional biopsy.
Even with removal, PASH can return. In rare cases, a doctor may recommend a mastectomy and breast reconstruction if PASH has resulted in massive breast enlargement, and pain or persistent discomfort.
PASH is a benign condition. No complications or deaths have been associated with PASH, and medical intervention usually looks to relieve discomfort and rule out other conditions.
Because the condition can mimic breast cancer as well as noncancerous breast lumps like fibroadenomas, investigation, evaluation, and follow-up are highly advised.