Diffuse Pseudoangiomatous Stromal Hyperplasia of the Breast: a Case Report and a Review of the Radiological Characteristics

JBR–BTR, 2014, 97: 81-83.

DIFFUSE PSEUDOANGIOMATOUS STROMAL HYPERPLASIA OF THE BREAST: A CASE REPORT AND A REVIEW OF THE RADIOLOGICAL CHARACTERISTICS

C. Mai¹, B. Rombaut², K. Hertveldt³, B. Claikens¹, P. Van Wettere¹

Pseudoangiomatous stromal hyperplasia is a benign mesenchymal tumor of the breast. It is a rare condition and until a few years mainly described in pathological and surgical literature. Here, we provide a case report of PASH and an overview of its radiological features.

Key-word: Breast neoplasms.

Pseudoangiomatous stromal hyperplasia (PASH) is a benign entity of the breast. It is a histological diagnosis and is characterised by a network of vascular-like clefts lined by endothelial-like spindle cells, against a background of stromal hyperplasia. Previously thought to be rare with only about a hundred cases described in literature, PASH is now diagnosed with increasing frequency. The non-mass-forming or diffuse form of PASH is believed to have an incidence of 23% in breast biopsies and has been reported in 25% of cases of gynecomastia (1). The clinical spectrum varies from incidental microscopic findingsto a focal A B palpable or non-palpable mass. One Fig. 1. — Ultrasound of the breasts. A. Axial image through the supra-areolar region case of PASH presenting as a rapidly of the left breast. Presence of glandular tissue. B. Axial image through the supra-areolar growing mass has been described in region of the right breast. Confirmation of larger amount of glandular tissue in the right literature (2). Histological and radio- breast, compared with the left breast. There are no signs of mastitis. logical, we can make a distinction between diffuse non-mass forming PASH and nodular PASH, which is less frequent. However, most case reports in radiological literature is of nodular PASH, which is indistin- guishable from fibroadenoma (on mammography, ultrasound and MRI). Here, we wish to report a case of diffuse PASH with its mammographic, ultrasonographic and mag- netic resonance imaging findings.

Case report

A 33-year-old woman presented at the gynaecologist with the chief Fig. 2. — Precontrast T2-weighted axial view images. Larger right breast with diffuse complaint of a painful right breast heterogeneous T2 hyperintense signal alterations. and pain at the right axillary region. Clinical examination showed some mild redness and tenderness on the right breast. The patient was treated mal. Mammography showed a larger confirmed a larger amount of glan- with antibiotics for suspected masti- amount of dense glandular tissue in dular tissue in the right breast, com- tis. She showed some improvement, the right breast (the mammography pared with the left breast (Fig. 1). but because of remaining tender- couldn’t be retrieved for publication). There were no signs of mastitis. ness additional tests were done. There was no architectural distortion, Because of these non-specific Blood results were completely nor- nor microcalcifications. Ultrasound changes, MRI of the breast was performed. Precontrast axial view T2-weighted images showed a larger right breast with diffuse heteroge- From: 1. Department of Radiology, 2. Department of Gynaecology, 3. Department of Pathology, AZ Damiaan, Oostende. neous T2 hyperintense signal altera- Address for correspondence: Dr C. Mai, M.D., Dept of Radiology, UZ Leuven, Herestraat tions (Fig. 2). On contrast-enhanced 49, 3000 Leuven, Belgium. E-mail: [email protected] subtraction images there is a diffuse

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ma) or ILC (invasive lobular carcinoma) couldn’t be ruled out. According to the ACR BI-RADS grading system, the lesion was categorised as suspicious abnormality (category 4). Therefore, a vacuum-assisted biopsy with a 10 G needle was performed. This happened under the guidance of MRI, given the extent of the lesion and the fact it was best seen on MRI. Four biopsies of 1,5 cm length were taken in the retro-areolar region and six in the pre-pectoral space. This de- livered the pathological evidence of diffuse PASH (Fig. 5). A Discussion

Pseudoangiomatous stromal hyperplasia (PASH) is a mesenchymal tumor of the breast with benign clinical outcome. It is histologically characterised by a network of slit-like spaces lined by endothelial-like spindle cells against a background of stromal hyperplasia. It is a histological diagnosis and must be differenti- ated from a low grade angiosarco- ma, which has similar vascular clefts, but is lined by endothelial cells and contains blood cells. Also, pleomor- B phism, mitotic activity and necrosis is not present in PASH (3). Fig. 3. — T1 weighted axial view images. A. Precontrast images. B. Contrast-enhanced Because it is mainly diagnosed in subtraction images. On substraction images there is a diffuse heterogeneous contrast premenopausal women or postmeno- captation of the fibroglandular tissue in the right breast. There was no pathological pausal women under hormone re- nipple change, nor invasion in the pectoral muscle. There was no enhancement in the left breast. placement therapy, PASH is believed to be hormone-related (4). The presentation of PASH is non- non mass-like enhancement of the phase (Fig. 4). Because of the asym- specific. It can be a clinical insignifi- right breast (Fig. 3). The kinetic curve metric enhancement (only in the cant microscopic finding or a diffuse showed slow rising in the initial right breast), multicentric carcinoma, disease presenting as gynecomastia phase and a plateau on the delayed such as IDC (invasive ductal carcino- or detected coincidentally on screen-

A 3 1

Fig. 4. — Dynamic contrast-enhanced MRI of the right breast. A. Point 1 and 2 are put in enhancing pathologic breast tissue and match respectively the solid line and the dashed line on the kinetic enhancement curve. Point 3 is put in normal enhancing breast tissue and matches the dotted line. B. On the kinetic enhancement curve. There is a rapid initial enhancement of the pathologic breast tissue with plateau pattern in the delayed phase (after 2 minutes). There is no wash-out B

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extent of disease, including the presence of multifocal or multicentric disease. If there are any suspicious features from sampling, further sampling is needed because PASH can coexist with malign processes. When PASH is diagnosed, no further inter- vention is needed given the benign course of PASH. A large study by Celliers et al. (4) for example investi- gated 73 patients diagnosed with PASH with a follow-up period between one and eight years. This study showed that not one patient developed cancer. But in case of co- existent malign disease or if patient prefers, PASH can be excised. In the same study there was one case of re- current disease at the same site. In Fig. 5. — Biopsy specimen 100x HE staining showing a network the literature recurrence rate after of slit-like spaces lined by endothelial-like spindle cells against a excision range from 15 to 22% (4). background of stromal hyperplasia. References

ings mammography. In rare cases it non-mass like clump of enhance- 1. Irshad A., et al.: Rare Breast Lesions: can present as a firm, painless and ment with a plateau or persistent Correlation of Imaging and Histologic mobile mass (nodular PASH) with no phase (6). In our case the distribution Features with WHO Classification. associated nipple or skin change. As pattern of non-mass like enhance- RadioGraphics, 2008, 28: 1399-1414. stated in previous studies (5), the ment is diffuse and asymmetric, 2. Teh H.-S., Chiang S.-H., Leung J., most patients with the clinical which haven’t been described be- Mancer J.: Rapidly Enlarging Tumoral Pseudoangiomatous Stromal Hyper- presentation of PASH had no mam- fore. While nodular PASH is mostly plasia in a 15-Year-Old Patient. J Ul- mographic abnormalities. The most classified in the ACR BI-RADS sys- trasound Med, 2007, 26: 1101-1106. frequent abnormalities on mam- tem as category 2 (benign findings) 3. Salvador R., Lirola J.L., Domínguez mography were of a dens homoge- or 3 (probably benign findings), dif- R., López M., Risueño N.: Pseudo-an- neous mass with smooth to partially fuse PASH is more often classified as giomatous stromal hyperplasia pre- or even ill-defined borders, and sec- category 4 (suspicious abnormali- senting as a breast mass: imaging ond as a localised increased stroma ties) (7). For detaining pathological findings in three patients. Breast, or focal asymmetric density. The evidence fine-needle aspiration cy- 2004, 13: 431-435. majority gets a score of three accord- tology is frequently unsatisfactory 4. Celliers L., Wong D.D., Bourke A.: Pseudoangiomatous stromal hyper- ing to the BI-RADS scoring system: because there is cytological overlap plasia: a study of the mammographic probably benign lesion. with fibroadenoma, there are a lot of and sonographic features. Clin Radiol, Ultrasound is normal in most dry samples (samples with no cells) 2010, 65: 145-149. cases of mammographic detected and often there could not be discrim- 5. Hargaden G.: Analysis of the Mammo PASH. The nodular form presents as inated from alternative diagnosis (4). graphic and Sonographic Features of a well-defined solid mass with hy- Often core needle biopsy is needed. Pseudoangiomatous Stromal Hyper- poechogenicity or heteroechogenici- In the late 1990s vacuum-assisted bi- plasia. Am J Roentgenol, 2008, 191: ty and with acoustic features ranging opsy came available. This sampling 359-363. from posterior enhancement to mild technique enables more accurate 6. Jones K.N., Glazebrook K.N., Reyn- olds C.: Pseudoangiomatous stromal posterior shadowing. Large lesions and larger tissue volume sampling, hyperplasia: imaging findings with can contain lace-like reticula (echo- what makes it most appropriate in pathologic and clinical correlation. genic or hypoechogenic) and areas case of microcalcifications and tis- Am J Roentgenol, 2010, 195: 1036- of scattered cystic changes or even sue distortion or asymmetry in den- 1042. central hyperechogenic areas (1, 3). sity (8). Ultrasound is the first-line 7. Agrawal G., Su M.Y., Nalcioglu O., On MRI images nodular PASH has mode for guiding breast biopsy be- Feig S.A., Chen J.H.: Significance of the same characteristics as a fibroad- cause of its availability, low cost and breast lesion descriptors in the ACR enoma, with rapid enhancement in no need for ionizing radiation. For le- BI-RADS MRI lexicon. Cancer, 2009, the two minutes after contrast injec- sions that are only visible on mam- 115: 1363-1380. 8. O’flynn E.A.M., Wilson A.R.M., tion, followed by a slowly increasing mography, like microcalcifications, Michell M.J.: Image-guided breast enhancement during the rest of the stereotactic guidance is the choice. biopsy: state-of-the-art. Clin Radiol, examination (3). While diffuse PASH MRI is increasingly used because it 2010, 65: 259-270. presents as a focal or segmental gives a precise determination of the

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