IS Case 147: Pseudoangiomatous Stromal Hyperplasia
Imaging Sciences URMC 2008
Publication Date: 2009-05-21
The patient is an otherwise healthy 28-year-old with a lump in her right breast. She had not been aware of it prior to a physician examination. She describes the mass as about the size of the nickel and slightly tender. It has not changed since she was first made aware of it. She has never had any previous breast problems or breast surgeries.
Imaging Findings: Mammogram findings: At the site of the radiopaque marker superior lateral to the right nipple, there is an non-calcified oval superficial well-circumscribed mass measuring up to 2.4 cm.
Ultrasound findings:Ultrasound of the palpable lump superior and lateral to the right nipple reveals a superficial oval well circumscribed benign appearing hypoechoic mass measuring 2.4 x 2.6 x 0.8 cm. There is some vascularity of the mass. There is no posterior enhancement or shadowing.
Pseudoangiomatous Stromal Hyperplasia
Pseudoangiomatous stromal hyperplasia is a benign proliferation of breast stromal cells. The condition was first described in 1986 by Vuitch, et al . The characteristic histology is a complex pattern of anastomosing channels lined by fibroblasts cells simulating endothelial cells. The pseudovascular spaces seen with the lesion is thought to arise from separation of stromal collagen fibers. There is no evidence of mitoses, atypia, or pleomorphism. A similar histology is seen in normal mammary stroma during the luteal phase of the menstrual cycle, suggesting that PASH may arise as a response to progesterone in estrogen activated tissue. Other studies have been able to label the stromal cells of PASH with progesterone receptor antibodies further supporting the theory of a hormonal etiology. It is rare for PASH to manifest itself as a palpable nodule. The mammographic features of PASH have been described as a round or oval isodense mass with margins that may be circumscribed, indistinct or obscured that may show a halo of compressed fat and almost never calcifies. The sonographic findings have been described as hypoechoic or slightly heterogeneous macrolobulated mass. There are currently no scientifically derived standards for management for PASH. A management similar to a fibroadenoma has been proposed where small lesions are managed conservatively with observation (usually 6 months follow-up) and large or growing lesions are excised with a wide margin. Local recurrence is common if excision is not complete.
- Vuitch MF, Rosen PP, Erlandson RA. Pseudoangiomatous hyperplasia of mammary stroma. Hum Pathol. 1986 Feb;17(2):185-91. [PMID: 3949338]
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