Molecular breast imaging (MBI) is a novel nuclear medicine imaging tool that detects uptake of technetium 99m sestamibi in breast lesions. We present the imaging findings of pseudoangiomatous stromal hyperplasia (PASH) on magnetic resonance imaging (MRI) and MBI.

Molecular Breast Imaging in Pseudoangiomatous Stromal Hyperplasia

Judy C. Boughey, MD,¹ Cindy Tortorelli, MD,^2‚ Carrie Hruska, PhD,² Michael O’Connor, PhD,^2‚ and Deborah Rhodes, MD³

Contact: Aikaterini Leventi, Surgical Oncology Clinic, Heraklion University Hospital, Faculty of Medicine, University of Crete, 1352 Voutes, Heraklion, Crete, Greece. E-mail: This e-mail address is being protected from spambots. You need JavaScript enabled to view it , Fax: 00302810392382.

Citation: Boughey JC, Tortorelli C, Hruska C, O’Connor M, Rhodes D. Molecular breast imaging in pseudoangiomatous stromal hyperplasia. J Surg Radiol. 2010 Jul 1;1(1). Download PDF Molecular Breast Imaging in Pseudoangiomatous Stromal Hyperplasia 1397 Kb Received: May 2, 2010; Accepted: May 31, 2010; Published: May 31, 2010 Copyright: © 2010 Surgisphere Corporation. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Contents - Introduction - Case Report - Discussion - References

Introduction

Molecular breast imaging (MBI) is a novel nuclear medicine imaging technique used to image breast lesions. Technetium 99m (Tc99m) sestamibi is injected intravenously and is taken up by breast tumors. MBI detects this Tc99m sestamibi uptake using dual head Cadmium-Zinc-Telluride (CZT) semiconductor detectors. MBI is being studied extensively in screening for and detection of invasive breast cancer and ductal carcinoma in situ.^1,2 Pseudoangiomatous stromal hyperplasia (PASH) is a benign condition of the breast which frequently presents as a palpable mass. The sonographic, mammographic and magnetic resonance imaging (MRI) characteristics of PASH have been previously described in several reports.³ We present a case report where MBI was critical in the diagnosis of PASH and present the imaging findings.

Case Report

A 35 year old woman presented with a palpable abnormality in the right breast on routine clinical examination. At age 16 (nineteen years prior to this presentation), she was treated for left breast rhabdomyosarcoma with mastectomy, implant reconstruction, adjuvant chemotherapy (vincristine, Adriamycin, cisplatin and Cytoxan) and radiation to the left chest wall, supraclavicular lymph nodes, and axillary lymph nodes. She subsequently underwent right breast reduction twice. In the current presentation, physical examination revealed a palpable thickening at the 10 o’clock position of the right breast. On questioning, the patient had experienced some tenderness in this area associated with her menstrual cycle. Mammography showed no abnormalities. Focused ultrasound of the area revealed normal breast parenchyma and no focal masses. The patient continued with clinical observation and repeat screening mammogram one year later also showed no areas of concern. The patient participated in a research study and underwent MBI with 20mCi technetium 99m sestamibi. MBI revealed a 2.3 x 2.2 cm focus of uptake in right upper outer quadrant of the breast (Figure 1).

Figure 1. Molecular breast imaging CC (left) and MLO (right) views showing 2.2 by 2.3 cm area of focal uptake of technetium 99m sestamibi in the upper outer quadrant of the right breast.

As a result of the MBI, diagnostic mammography and repeat ultrasound were completed for additional imaging. Spot compression magnification views of the right breast upper outer quadrant revealed a 2 cm vague focal asymmetry with partial effacement. Ultrasound of this area revealed no focal masses. The area of palpable concern correlated with a ridge of breast parenchyma, but no associated mass was seen. MRI demonstrated a segmental area of clumped, persistent enhancement measuring 4.1 x 2.5 x 2.0 cm (Figure 2). MRI-guided biopsy revealed PASH. One year later, the patient elected to undergo nipple sparing mastectomy with immediate reconstruction. Pathology revealed florid PASH forming an ill-defined mass in the upper outer quadrant measuring 3.6 x 2.5 x 2.3 cm.

Figure 2. Sagittal (left) and axial (right) post-contrast T1 MRI images showing clumped segmental enhancement in the upper outer right breast.

Discussion

PASH is an unusual benign disease of the breast. It is usually diagnosed on percutaneous biopsy for a palpable abnormality or an imaging abnormality. PASH classically presents in patients in their late 30s or early 40s with an age range of 14-67 years. PASH is a common entity that presents with benign imaging features without evidence of malignant potential. The rate of recurrence of PASH after excision ranges from 2% to 22%.^3-5

Sonographically, PASH usually appears as a well-circumscribed mass, either hypoechoic or isoechoic. On MRI, PASH can present as a mass, similar to a fibroadenoma⁷ or clumped enhancement^6,8 that exhibits either a rapid or persistent kinetic pattern.⁷ In this case, MRI revealed a clumped segmental persistent enhancement.

Mammographic characteristics of PASH include a non-calcified, circumscribed mass or a focal asymmetry,^3,6 although no diagnostic findings may be present on mammography. When calcifications are seen with PASH, it may be due to a concomitant ductal carcinoma in situ or atypical ductal hyperplasia. PASH can co-exist with a malignant process, so any suspicious features on imaging should prompt further work up and a possible excisional biopsy.

This is the first report of MBI findings of PASH. PASH does demonstrate uptake of Tc99m. MBI can be useful in problem solving, particularly in the workup of questionable palpable lesions when initial imaging studies are negative. MBI plays a useful role in the work up of palpable abnormalities in the breast, especially for problem solving in the presence of negative imaging on mammography and ultrasound. In this case of PASH, MBI detected focal uptake of Tc99m. When focal uptake is seen on MBI and biopsy reveals PASH, these findings can be concordant and may not necessarily require excision. Radiologic and pathologic correlation remains important.

References

1. Hruska CB, Boughey JC, Phillips SW, et al: Scientific Impact Recognition Award: Molecular breast imaging: a review of the Mayo Clinic experience. Am J Surg 196:470-6, 2008. | CrossRef | PubMed |
2. Hruska CB, Phillips SW, Whaley DH, et al: Molecular breast imaging: use of a dual-head dedicated gamma camera to detect small breast tumors. AJR Am J Roentgenol 191:1805-15, 2008. | CrossRef | PubMed |
3. Hargaden GC, Yeh ED, Georgian-Smith D, et al: Analysis of the mammographic and sonographic features of pseudoangiomatous stromal hyperplasia. AJR Am J Roentgenol 191:359-63, 2008. | CrossRef | PubMed |
4. Vuitch MF, Rosen PP, Erlandson RA: Pseudoangiomatous hyperplasia of mammary stroma. Hum Pathol 17:185-91, 1986. | CrossRef |
5. Powell CM, Cranor ML, Rosen PP: Pseudoangiomatous stromal hyperplasia (PASH). A mammary stromal tumor with myofibroblastic differentiation. Am J Surg Pathol 19:270-7, 1995. | CrossRef | PubMed |
6. Leung JW, Sickles EA: Developing asymmetry identified on mammography: correlation with imaging outcome and pathologic findings. AJR Am J Roentgenol 188:667-75, 2007. | CrossRef | PubMed |
7. Cardenosa G, Shaw J: Radiology-pathology correlation of some uncommon breast lesions. Semin Breast Dis 4:100-115, 2001.
8. Jones K, Glazebrook K: Mammographic, sonographic and MRI findings of pseudoangiomatous stromal hyperplasia with pathologic and clinical correlation. AJR Am J Roentgenol 190:A79-A86, 2008.