Clusterin expression in elastofibroma dorsi

Ariane Aigelsreiter¹, Martin Pichler², Thomas Pixner¹, Elke Janig³, Monika Schuller¹, Carolin Lackner¹, Susanne Scheipl⁴, Alfred Beham¹ and Sigrid Regauer<sup>1

1</sup>Institute of Pathology, Medical University of Graz, Austria, ²Department of Internal Medicine, Division of Oncology, Medical University of Graz, Austria, ³Department of Dermatology and Venerology, Medical University of Vienna, Austria and ⁴Department of Orthopaedics and Orthopaedic Surgery, Division of Surgery, Medical University of Graz, Austria.

Offprint requests to: Dr. Ariane Aigelsreiter, Institute of Pathology, Medical University of Graz, Auenbruggerplatz 35, 8036 Graz, Austria. e-mail: ariane.aigelsreiter@klinikum-graz.at


Summary. Background: Elastofibroma dorsi is a benign soft tissue lesion composed of abnormal elastic fibers. Degenerated elastic fibers in skin and liver are associated with clusterin, an apoprotein that shares functional properties with small heat shock proteins. We evaluated the staining pattern and possible role of clusterin in elastofibroma dorsi. Material and methods: Twenty-one subcutaneous elastofibromas from the scapular region were evaluated with Elastica van Gieson and Orcein stains, immunohistochemically with antibodies to clusterin, smooth muscle actin, S-100, vimentin and CD34 and correlated with clinical data with respect to physical trauma. Results: Clusterin correlated with the staining pattern of Elastica van Gieson and labelled abnormal broad coarse fibrillar and globular elastic fibers in all elastofibromas. Orcein stains additionally identified fine oxytalan fibers which were not stained by clusterin. Clusterin staining was observed only on the outside of the elastin fibers, while the cores of fibers and globules were unstained. 4/21 elastofibromas showed cellular nodules with a myxoid/collagenous stroma. The round to oval cells showed cytoplasmic staining with vimentin and clusterin; CD34 labelled mostly cell membranes. The cells lacked SMA and S-100 expression. The central areas of the nodules were devoid of elastic fibers, but the periphery contained coarse fibers and globules. 9/11 patients, for whom clinical data were available, reported trauma to the scapular region. Conclusion: Many investigated ED were associated with trauma, which supports a reactive/degenerative etiology of ED. The abnormal large elastic fibers in all ED were enveloped by clusterin. Clusterin deposition may protect elastic fibers from degradation and thus contribute indirectly to the tumor-like presentation of ED. Histol Histopathol 28, 597-603 (2013)

Key words: Tumorigenesis, Immunohistochemistry, Elastic fibers, Heat shock protein

DOI: 10.14670/HH-28.597