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Table of Contents
Year : 2019  |  Volume : 2  |  Issue : 1  |  Page : 22-25

Pseudoangiomatous stromal hyperplasia presenting as an enlarging breast mass: A case report

1 Department of General Surgery, Amrita Institute of Medical Sciences, Kochi, Kerala, India
2 Department of Pathology, Amrita Institute of Medical Sciences, Kochi, Kerala, India
3 Department of Radiology, Amrita Institute of Medical Sciences, Kochi, Kerala, India

Date of Web Publication26-Jun-2019

Correspondence Address:
Dr. Mala M Sharma
Department of General Surgery, Amrita Institute of Medical Sciences, Ponekkara PO, Edapally, Kochi, Kerala
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/JCO.JCO_25_18

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Pseudoangiomatous stromal hyperplasia (PASH) is an occasional histological finding in the breast tissue, which rarely presents as a clinical mass. We here report a case of progressively increasing breast lump that had radiological ambiguous findings but on excision proved to be PASH on histology and immunohistochemistry (IHC). On microscopy, PASH has to be distinguished from low-grade vascular tumors as stromal spaces in it mimic the endothelium-lined vascular spaces. In view of nonspecific radiological picture, histopathological confirmation by core needle or excision is mandatory. It may coexist with in situ or invasive breast malignancies also. IHC with stromal and vascular markers is the key to diagnosis of PASH; also these tumors show positivity with progesterone markers pointing to endocrine stimulation as a possible etiology. In asymptomatic PASH, expectant management is indicated; however, in symptomatic and enlarging masses, surgical treatment should be preferred.

Keywords: Breast mass, CD34, myofibroblastic proliferation, PASH, progesterone receptors, pseudoangiomatous stromal hyperplasia

How to cite this article:
Sharma MM, Nambiar A, Dharmarajan JP. Pseudoangiomatous stromal hyperplasia presenting as an enlarging breast mass: A case report. J Curr Oncol 2019;2:22-5

How to cite this URL:
Sharma MM, Nambiar A, Dharmarajan JP. Pseudoangiomatous stromal hyperplasia presenting as an enlarging breast mass: A case report. J Curr Oncol [serial online] 2019 [cited 2023 Oct 2];2:22-5. Available from: http://www.https://journalofcurrentoncology.org//text.asp?2019/2/1/22/261474

  Introduction Top

PASH or pseudoangiomatous stromal hyperplasia is not so rare a lesion found in microscopy of breast tissue removed or biopsied for various pathologies, but the clinical entity of a palpable breast mass with PASH histology and no other associated pathology is quite rare. In this report, we are documenting one such case. Histologically the challenge in PASH lies in differentiating it from a low-grade sarcoma that it mimics.[1] The stromal proliferations with complex anastomosing channels of PASH require to be recognized separately from the angiomatous proliferation and endothelial-lined vascular spaces of low-grade angiosarcoma, which presents as a breast mass in a similar clinical scenario.[2] This histological entity was first described in 1986 by Vuitch et al.,[3] and subsequently as an incidental microscopic finding in 40 breast biopsies by Powel in 1995.[4] Further studies have documented the presence of PASH in mastectomy specimens including those of gynecomastia.[5]

  Case Report Top

A 40-year-old lady presented with a painful lump in the right breast of 4-year duration with a recent enlargement in past 4 months. There were no other associated symptoms. She was a Para 2 with regular menstrual cycles. On clinical examination, she had a solitary 8×6cm soft-to-firm, well-defined lump in the right breast at 12 o’clock position 4cm above the areolar rim. The lump was freely mobile in the breast as well as on the pectoral muscles and the overlying skin was normal. There was no axillary lymphadenopathy. Left breast was normal. With this scenario, the patient underwent a triple assessment.

The mammogram showed extremely dense breasts with no suspicious mass, architectural distortion, or suspicious calcification. Ultrasonogram (USG) over the area of clinical concern showed a deeply located hypoechoic solid mass with indistinct margins [Figure 1]A. The mass was about 2.0×1.8×2.0cm with poor vascularity and dense posterior shadowing. A problem-solving magnetic resonance imaging (MRI) of the breast was performed on account of indeterminate features of the mass and dense breasts for better lesion characterization and accurate targeting of biopsy. On 11th day of last menstrual period, the lady underwent gadolinium-enhanced MRI Breast in a 1.5-T MRI unit with a dedicated 8-channel breast coil. The right breast was larger in size as compared to left. A T2 bright heterogeneous area in upper quadrant middle third measuring approximately 6.3×5.3cm showed no increased vascularity on postcontrast sequences or restriction in diffusion-weighted sequences [Figure 1]B. A USG-guided biopsy with a 14-G needle was taken from the area of concern. The core biopsy showed normal breast lobules and parenchyma with PASH-like foci.
Figure 1: (A) Ultrasound showing deeply located irregular hypoechoic area with indistinct margins having poor vascularity and posterior shadowing. (B) Magnetic resonance imaging shows right breast larger than left, T2 sequence with fat saturation shows no abnormal enhancement or diffusion restriction

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Keeping in mind the large and increasing size, the patient was offered the option of surgery. The patient underwent a wide local excision (WLE) of the lesion through a transverse supra areolar incision and the specimen was marked [Figure 2]A and [B].
Figure 2: (A) Tumorous lesion been excised from right breast by transverse incision. (B) Surgical specimen

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On histopathology, the specimen was a 5.5cm × 5.8cm × 4cm lesion, which was fibrotic and gray on cutting. On microscopy, the stromal cells were seen forming a complex network of anastomosing spaces [Figure 3]A and [B]. These pseudovascular spaces were lined by myofibroblasts with attenuated nuclei, which stained positive for vimentin and CD34 [Figure 3]C and [D]. There was no evidence of ductal carcinoma in situ (DCIS) or malignancy. Immunohistochemistry further showed progesterone receptor positivity and absence of endothelial markers thus clinching the diagnosis of PASH.
Figure 3: (A) Slit-like spaces lined by stromal cells in a hyalinized stroma (×100). (B) High-power photo showing pseudovascular slit-like spaces lined by myofibroblasts (H and E, ×400). (C) CD34-positive myofibroblasts lining the slit-like spaces. (D) Myofibroblasts lining pseudovascular spaces are positive for CD34

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The point worth noting, in this case, is that imaging findings on mammography were nonspecific and USG of breast showed an indeterminate mass with size much smaller than what was felt clinically and later confirmed on histology. However, MRI breast showed an accurate representation of the size.

  Discussion Top

PASH though a frequent histological finding in the breast is a rare clinical entity.[6] When it presents, it has been described as a firm, painless, well-circumscribed, and freely mobile mass mimicking fibroadenoma. However, cases have been reported of rapidly growing masses raising suspicion of malignancy and rarely giving rise to massive lesions causing cosmetic disfigurement and warranting mammoplasty or even mastectomy in adolescent girls.[7],[8],[9]

On imaging, PASH may or may not show as calcification. USG findings range from well-circumscribed hyperechoic to ill-defined hypoechoic appearance. On MRI, T1-weighted images may show isointense mass and T2 images may show linear reticular “lacelike” pattern with slit-like spaces within the lesion.[10] Tumorous PASH, however, does not have any distinctive features. Hence, for confirmation of diagnosis and exclusion of malignancy, histology is mandatory.

It has also been observed in many studies that PASH, when detected in mammographic screening, is usually seen as solitary calcified mass. However, in patients presenting as a palpable mass, the mammogram showed normal findings.[11] This difference in radiological features in asymptomatic screen-detected individuals and symptomatic patients has been shown to be statistically significant as also seen in our case where radiological findings were much understated compared to clinical. The aforementioned fact also underlines the importance of histological confirmation.

The pathogenesis of PASH is uncertain but studies have suggested an exogenous or endogenous endocrine stimulation leading to aberrant myofibroblastic proliferation. This fact is well supported by the presence of estrogen and progesterone receptors in a large number of tumors. An additional fact is that PASH usually presents in premenopausal women and postmenopausal women on hormone supplementation.[10] Also, the size of the tumor is much larger in younger women. Reports of PASH in breast tissues of male patients with gynecomastia and transgenders on exogenous hormones also substantiate the same.[2] In further support is the fact that PASH has shown a favorable response to antihormone manipulation like tamoxifen.[12],[13]

Though PASH is a benign entity, from histological point two aspects need to be paid attention to. First, it needs to be differentiated from low-grade angiosarcoma, which also clinically presents in premenopausal women with a breast mass and histologically shows slit-like vascular spaces lined by endothelium. In angiosarcoma, the anastomosing vascular channels contain red blood cells and invade the surrounding breast tissue with no associated collagen stroma. IHC will show positive for vascular markers such as CD31 and factor VIII,[1] whereas PASH tissue shows positivity for CD34 consistent with a myofibroblastic stromal origin of the tumor. The presence of progesterone receptors also favors PASH.[10],[14]

The second aspect to be kept in mind in cases of PASH is that these lesions are quite often co-detected with DCIS and invasive tumors. This frequent association mandates full evaluation and multidisciplinary approach to all cases with clinical and radiological suspicion even in presence of PASH because the association has proved to be mostly coincidental with no direct correlation. PASH is not premalignant and only one single report of malignant transformation has been documented.[15] Actually, a study had shown that the risk of developing malignancy is less in women with PASH than without.[16]

Surgical management of PASH is indicated in cases of large palpable masses or rapidly enlarging masses and other cases where other malignant pathologies cannot be ruled out. In large PASH tumors, the surgery may range from a simple WLE to mastectomy or mammoplasty, depending on the age, size, and patient preferences. Simple excision should be discouraged as recurrence has been documented especially because the hormonal stimulatory environment persists even after. Small incidental lesions can be carefully selected and kept on clinical and radiological follow-up.

In conclusion, it is important to emphasize that the diagnosis of PASH may not be a rarity from the point of view of a pathologist, it being an occasional incidental finding in breast tissue. However, for a clinician, in a patient presenting with a palpable mass, when there is discordance in clinical imaging and pathological findings, ultrasound-guided core biopsy may not all the time be the conclusively given diagnosis. In these circumstances, after excluding the presence of more worrisome occult lesions on excision biopsy specimen, it is the pathologist alone who with the help of IHC can provide the final diagnosis. Management of these patients must be performed with a multidisciplinary approach keeping in mind the symptoms of the patient and the coexistence of PASH with other pathologies.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

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Conflicts of interest

There are no conflicts of interest.

  References Top

Ibrahim RE, Sciotto CG, Weidner N. Pseudoangiomatous hyperplasia of mammary stroma. Some observations regarding its clinicopathologic spectrum. Cancer 1989;63:1154-60.  Back to cited text no. 1
Bowman E, Oprea G, Okoli J, Gundry K, Rizzo M, Gabram-Mendola S, et al. Pseudoangiomatous stromal hyperplasia (PASH) of the breast: A series of 24 patients. Breast J 2012;18:242-7.  Back to cited text no. 2
Vuitch MF, Rosen PP, Erlandson RA. Pseudoangiomatous hyperplasia of mammary stroma. Hum Pathol 1986;17:185-91.  Back to cited text no. 3
Powell CM, Cranor ML, Rosen PP. Pseudoangiomatous stromal hyperplasia (PASH). A mammary stromal tumor with myofibroblastic differentiation. Am J Surg Pathol 1995;19:270-7.  Back to cited text no. 4
Milanezi MF, Saggioro FP, Zanati SG, Bazan R, Schmitt FC. Pseudoangiomatous hyperplasia of mammary stroma associated with gynaecomastia. J Clin Pathol 1998;51:204-6.  Back to cited text no. 5
Vasuki R, Thanmaran NB, Devi AKK, Moothedath RM, Satheesh Kumar M. Tumour forming pseudoangiomatous stromal hyperplasia: A case report. Int Surg J 2017;4:2854.  Back to cited text no. 6
Testori A, Alloisio M, Errico V, Bottoni E, Voulaz E, Fernandez B, et al. Pseudoangiomatous stromal hyperplasia—a benign and rare tumor of the breast in an adolescent: A case report. J Med Case Rep 2017;11:284.  Back to cited text no. 7
Sng KK, Tan SM, Mancer JF, Tay KH. The contrasting presentation and management of pseudoangiomatous stromal hyperplasia of the breast. Singapore Med J 2008;49:e82-5.  Back to cited text no. 8
Solomou E, Kraniotis P, Patriarcheas G. A case of a giant pseudoangiomatous stromal hyperplasia of the breast: Magnetic resonance imaging findings. Rare Tumors 2012;4:e23.  Back to cited text no. 9
Virk RK, Khan A. Pseudoangiomatous stromal hyperplasia: An overview. Arch Pathol Lab Med 2010;134:1070-4.  Back to cited text no. 10
Celliers L, Wong DD, Bourke A. Pseudoangiomatous stromal hyperplasia: A study of the mammographic and sonographic features. Clin Radiol 2010;65:145-9.  Back to cited text no. 11
Pruthi S, Reynolds C, Johnson RE, Gisvold JJ. Tamoxifen in the management of pseudoangiomatous stromal hyperplasia. Breast J 2001;7:434-9.  Back to cited text no. 12
Seltzer MH, Kintiroglou M. Pseudoangiomatous hyperplasia and response to tamoxifen therapy. Breast J 2003;9:344.  Back to cited text no. 13
Anderson C, Ricci A Jr, Pedersen CA, Cartun RW. Immunocytochemical analysis of estrogen and progesterone receptors in benign stromal lesions of the breast. Evidence for hormonal etiology in pseudoangiomatous hyperplasia of mammary stroma. Am J Surg Pathol 1991;15:145-9.  Back to cited text no. 14
Jaunoo SS, Thrush S, Dunn P. Pseudoangiomatous stromal hyperplasia (PASH): A brief review. Int J Surg 2011;9:20-2.  Back to cited text no. 15
Degnim AC, Frost MH, Radisky DC, Anderson SS, Vierkant RA, Boughey JC, et al. Pseudoangiomatous stromal hyperplasia and breast cancer risk. Ann Surg Oncol 2010;17:3269-77.  Back to cited text no. 16


  [Figure 1], [Figure 2], [Figure 3]


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