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Incidental Mammary Fibromyoblastoma on 82Rb Myocardial Perfusion Imaging Matthieu Pelletier-Galarneau, MD, MSc,* Patrick Martineau, MD, PhD,* and Ross A. Davies, MD, FRCPC, FACC† Abstract: 82Rb is frequently used in PET myocardial perfusion imaging to detect ischemia. We present the case of a 64-year-old man referred for PET myocardial perfusion imaging to rule out ischemia. On PET images, an abnormal focus of uptake was present in the subcutaneous soft tissue overlying the right chest, which corresponded to a soft-tissue nodule on CT. This lesion was biopsied and proved to be a mammary fibromyoblastoma, an extremely rare and benign lesion. This case is presented to emphasize the importance of reviewing extracardiac structures on PET/CT myocardial perfusion studies. (Clin Nucl Med 2015;40: 343–344)
Received for publication June 26, 2014; revision accepted October 24, 2014. From the *Division of Nuclear Medicine, University of Ottawa; and †Division of Cardiology, University of Ottawa Heart Institute, Ottawa, Ontario, Canada. Conflicts of interest and sources of funding: none declared. Reprints: Matthieu Pelletier-Galarneau, MD, MSc, Division of Nuclear Medicine, Ottawa Hospital, University of Ottawa, General Campus, 501 Smyth Rd, Ottawa, Ontario, Canada K1H 8 L6. E-mail: [email protected]. Copyright © 2014 Wolters Kluwer Health, Inc. All rights reserved. ISSN: 0363-9762/15/4004–0343
REFERENCES 1. Baggish AL, Boucher CA. Radiopharmaceutical agents for myocardial perfusion imaging. Circulation. 2008;118:1668–1674. 2. Sehweil AM, McKillop JH, Milroy R, et al. Mechanism of 201Tl uptake in tumours. Eur J Nucl Med. 1989;15:376–379. 3. Carli MFD, Dorbala S, Meserve J, et al. Clinical myocardial perfusion PET/CT. J Nucl Med. 2007;48:783–793. 4. Mirpour S, Khandani AH. Extracardiac abnormalities on rubidium-82 cardiac positron emission tomography/computed tomography. Nucl Med Commun. 2011;32: 260–264. 5. Wargotz ES, Weiss SW, Norris HJ. Myofibroblastoma of the breast. Sixteen cases of a distinctive benign mesenchymal tumor. Am J Surg Pathol. 1987;11:493–502. 6. Kataria K, Srivastava A, Singh L, et al. Giant myofibroblastoma of the male breast: a case report and literature review. Malays J Med Sci. 2012;19:74–76. 7. Klocke FJ, Baird MG, Lorell BH, et al. ACC/AHA/ASNC guidelines for the clinical use of cardiac radionuclide imaging—executive summary: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (ACC/AHA/ASNC Committee to Revise the 1995 Guidelines for the Clinical Use of Cardiac Radionuclide Imaging). Circulation. 2003;108: 1404–1418. 8. Strauss HW, Miller DD, Wittry MD, et al. Procedure guideline for myocardial perfusion imaging 3.3. J Nucl Med Technol. 2008;36:155–161.
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Pelletier-Galarneau et al
Clinical Nuclear Medicine • Volume 40, Number 4, April 2015
FIGURE 1. A 64-year-old man underwent 82Rb PET/CT myocardial perfusion imaging (MPI) for atypical chest pain. Besides moderate ischemia (not shown), abnormal 82Rb uptake in the right breast was also present. Axial image of the 82Rb PET (A) and corresponding axial CT image (B) show a focus of abnormal 82Rb uptake in the right breast (arrow), corresponding to a soft tissue nodule in the retroareolar region on CT. There is otherwise physiological myocardial and lung uptake.
FIGURE 2. Ultrasound (A) and mammogram (B) of the right breast demonstrate a well-defined retroareolar solid nodule that measures 1.2 0.9 cm. On ultrasound of the right axillary region (C), an abnormal lymph node measuring 1.3 0.3 cm was identified. The patient subsequently underwent ultrasound-guided core biopsy of the right breast nodule and abnormal axillary lymph node. The right breast nodule sample demonstrated a moderately cellular spindle cell lesion consistent with mammary myofibroblastoma. Biopsy results of the right axillary lymph node were consistent with a benign lymph node. 82Rb is a PET isotope with half-life of 76 seconds and is frequently used in PET MPI.1 It is a monovalent cationic analog of potassium sharing similar biological properties with 201Tl. Like 201Tl, 82Rb accumulates in myocardial tissue and extracardiac tissue through active transport via the NaK ATP transporters with uptake proportional to blood flow.2,3 Accumulation of 82Rb has previously been described in various malignancies including breast cancer, lung cancer, lymphoma, and multiple myeloma as well as in several benign lesions.4 First described by Wargotz et al5 in 1987, myofibroblastoma is a rare benign mesenchymal tumor arising from fibroblasts, affecting predominantly middle-aged men. Fewer than 100 cases have been reported in the literature to date.6 Besides the breast, it has been described in the popliteal fossa, head, neck, and genitals of both men and women.6 Radiological findings are consistent with a well-circumscribed lesion without calcifications. Review of raw data to identify attenuation artifacts and extracardiac uptake is recommended in current guidelines for SPECT MPI.7,8 However, with PET/CT perfusion imaging, assessment of raw data is not routinely done. This case reinforces the importance of reviewing extracardiac structures for incidental findings. 344
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2014 © Wolters Kluwer Health, Inc. All rights reserved. Copyright © 2015 Wolters Kluwer Health, Inc. All rights reserved.
Incidental Mammary Fibromyoblastoma on 82Rb Myocardial Perfusion Imaging Matthieu Pelletier-Galarneau, MD, MSc,* Patrick Martineau, MD, PhD,* and Ross A. Davies, MD, FRCPC, FACC† Abstract: 82Rb is frequently used in PET myocardial perfusion imaging to detect ischemia. We present the case of a 64-year-old man referred for PET myocardial perfusion imaging to rule out ischemia. On PET images, an abnormal focus of uptake was present in the subcutaneous soft tissue overlying the right chest, which corresponded to a soft-tissue nodule on CT. This lesion was biopsied and proved to be a mammary fibromyoblastoma, an extremely rare and benign lesion. This case is presented to emphasize the importance of reviewing extracardiac structures on PET/CT myocardial perfusion studies. (Clin Nucl Med 2015;40: 343–344)
Received for publication June 26, 2014; revision accepted October 24, 2014. From the *Division of Nuclear Medicine, University of Ottawa; and †Division of Cardiology, University of Ottawa Heart Institute, Ottawa, Ontario, Canada. Conflicts of interest and sources of funding: none declared. Reprints: Matthieu Pelletier-Galarneau, MD, MSc, Division of Nuclear Medicine, Ottawa Hospital, University of Ottawa, General Campus, 501 Smyth Rd, Ottawa, Ontario, Canada K1H 8 L6. E-mail: [email protected]. Copyright © 2014 Wolters Kluwer Health, Inc. All rights reserved. ISSN: 0363-9762/15/4004–0343
REFERENCES 1. Baggish AL, Boucher CA. Radiopharmaceutical agents for myocardial perfusion imaging. Circulation. 2008;118:1668–1674. 2. Sehweil AM, McKillop JH, Milroy R, et al. Mechanism of 201Tl uptake in tumours. Eur J Nucl Med. 1989;15:376–379. 3. Carli MFD, Dorbala S, Meserve J, et al. Clinical myocardial perfusion PET/CT. J Nucl Med. 2007;48:783–793. 4. Mirpour S, Khandani AH. Extracardiac abnormalities on rubidium-82 cardiac positron emission tomography/computed tomography. Nucl Med Commun. 2011;32: 260–264. 5. Wargotz ES, Weiss SW, Norris HJ. Myofibroblastoma of the breast. Sixteen cases of a distinctive benign mesenchymal tumor. Am J Surg Pathol. 1987;11:493–502. 6. Kataria K, Srivastava A, Singh L, et al. Giant myofibroblastoma of the male breast: a case report and literature review. Malays J Med Sci. 2012;19:74–76. 7. Klocke FJ, Baird MG, Lorell BH, et al. ACC/AHA/ASNC guidelines for the clinical use of cardiac radionuclide imaging—executive summary: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (ACC/AHA/ASNC Committee to Revise the 1995 Guidelines for the Clinical Use of Cardiac Radionuclide Imaging). Circulation. 2003;108: 1404–1418. 8. Strauss HW, Miller DD, Wittry MD, et al. Procedure guideline for myocardial perfusion imaging 3.3. J Nucl Med Technol. 2008;36:155–161.
Clinical Nuclear Medicine • Volume 40, Number 4, April 2015 Copyright © 2015 Wolters Kluwer Health, Inc. All rights reserved.
www.nuclearmed.com
343
Pelletier-Galarneau et al
Clinical Nuclear Medicine • Volume 40, Number 4, April 2015
FIGURE 1. A 64-year-old man underwent 82Rb PET/CT myocardial perfusion imaging (MPI) for atypical chest pain. Besides moderate ischemia (not shown), abnormal 82Rb uptake in the right breast was also present. Axial image of the 82Rb PET (A) and corresponding axial CT image (B) show a focus of abnormal 82Rb uptake in the right breast (arrow), corresponding to a soft tissue nodule in the retroareolar region on CT. There is otherwise physiological myocardial and lung uptake.
FIGURE 2. Ultrasound (A) and mammogram (B) of the right breast demonstrate a well-defined retroareolar solid nodule that measures 1.2 0.9 cm. On ultrasound of the right axillary region (C), an abnormal lymph node measuring 1.3 0.3 cm was identified. The patient subsequently underwent ultrasound-guided core biopsy of the right breast nodule and abnormal axillary lymph node. The right breast nodule sample demonstrated a moderately cellular spindle cell lesion consistent with mammary myofibroblastoma. Biopsy results of the right axillary lymph node were consistent with a benign lymph node. 82Rb is a PET isotope with half-life of 76 seconds and is frequently used in PET MPI.1 It is a monovalent cationic analog of potassium sharing similar biological properties with 201Tl. Like 201Tl, 82Rb accumulates in myocardial tissue and extracardiac tissue through active transport via the NaK ATP transporters with uptake proportional to blood flow.2,3 Accumulation of 82Rb has previously been described in various malignancies including breast cancer, lung cancer, lymphoma, and multiple myeloma as well as in several benign lesions.4 First described by Wargotz et al5 in 1987, myofibroblastoma is a rare benign mesenchymal tumor arising from fibroblasts, affecting predominantly middle-aged men. Fewer than 100 cases have been reported in the literature to date.6 Besides the breast, it has been described in the popliteal fossa, head, neck, and genitals of both men and women.6 Radiological findings are consistent with a well-circumscribed lesion without calcifications. Review of raw data to identify attenuation artifacts and extracardiac uptake is recommended in current guidelines for SPECT MPI.7,8 However, with PET/CT perfusion imaging, assessment of raw data is not routinely done. This case reinforces the importance of reviewing extracardiac structures for incidental findings. 344
www.nuclearmed.com
2014 © Wolters Kluwer Health, Inc. All rights reserved. Copyright © 2015 Wolters Kluwer Health, Inc. All rights reserved.
