Thesis
Retrospective histopathologic evaluation of fibroblastic versus myofibroblastic entities of the oral mucosa
University of Iowa
Master of Science (MS), University of Iowa
Spring 2016
DOI: 10.17077/etd.hhzib69b
Abstract
<p>The objective of this study is to use immunohistochemistry to determine whether myofibroma is a distinct entity or a variation of other fibroblastic entities. Staining patterns of vimentin, SMA and CD34 are evaluated in irritation fibromas, ulcerated fibromas, giant cell fibromas, inflammatory fibrous hyperplasias, focal keratosis and chronic mucositis, used in this study as a control group, and myofibromas. This study assesses whether myofibromas demonstrate similar staining patterns of vimentin, SMA and CD34 to the aforementioned lesions and if these stains are adequate in differentiating the entities.</p>
<p>Upon IRB approval, 46 cases of irritation fibroma, 45 cases of ulcerated irritation fibroma, 44 cases of giant cell fibroma, 47 cases of focal keratosis and chronic mucositis, and 23 cases of myofibroma were collected. Hematoxylin and eosin-stained slides were reviewed and immunohistochemistry of vimentin, SMA and CD34 was performed. Staining patterns were graded as 0, 1 and 2 (≤25%; ≤25-50%; and ≥50% respectively). Differences were analyzed by the Kruskal-Wallis exact test and Dunn's test for pairwise comparisons.</p>
<p>Vimentin demonstrated grade 2 positivity in all groups with 6.5% and 4.4% of irritation fibromas and myofibromas demonstrating grade 1 positivity, respectively. Smooth muscle actin was strongly positive in myofibroma (78.3%, grade 2, p < 0.05) but also demonstrated positivity in focal keratosis and chronic mucositis (2.1% grade 1), giant cell fibromas (4.6% grade 1, 4.6% grade 2), inflammatory fibrous hyperplasias (13.6% grade 1, 13.6% grade 2) and ulcerated irritation fibromas (6.7% grade 2, 8.9% grade 1) though this was not statistically significant. CD34 demonstrated statistically significant positivity in irritation fibromas (87% grade 2, 2.2% grade 1), ulcerated irritation fibromas (73.3% grade 2, 6.7% grade 1), and inflammatory fibrous hyperplasias (63.6% grade 2, 6.8% grade 1). CD34 also demonstrated positivity in giant cell fibromas (54.6% grade 2, 2.3% grade 1) and myofibromas (21.7% grade 2, 4.4% grade 1) though this was not statistically significant. The Dunn’s test for pairwise comparisons revealed statistically significant differences for CD34 staining between myofibroma and fibroma; myofibroma and focal keratosis and chronic mucositis; myofibroma and inflammatory fibrous hyperplasia; and between myofibroma and ulcerated fibroma.</p>
<p>The results indicate that smooth muscle actin immunohistochemistry is helpful but not definitive in delineating myofibroma as a separate entity. In addition, as other fibrous proliferations in our study also expressed smooth muscle actin, it is possible that smooth muscle actin expression correlates with the duration and chronic tissue assault associated with a lesion, thus supporting the theory that oral myofibromas are part of the spectrum of fibrous proliferations. The results also indicate that although CD34 is deemed a specific marker for solitary fibrous tumor, this marker was not reliable in distinguishing any of the entities from one another and may in fact not be specific for solitary fibrous tumor. Further studies are needed to support this claim.</p>
Details
- Title: Subtitle
- Retrospective histopathologic evaluation of fibroblastic versus myofibroblastic entities of the oral mucosa
- Creators
- Chandni Desai - University of Iowa
- Contributors
- John W. Hellstein (Advisor)Robert A. Robinson (Committee Member)Sherry Rene Timmons (Committee Member)Nidhi Q. Handoo (Committee Member)
- Resource Type
- Thesis
- Degree Awarded
- Master of Science (MS), University of Iowa
- Degree in
- Oral Science
- Date degree season
- Spring 2016
- DOI
- 10.17077/etd.hhzib69b
- Publisher
- University of Iowa
- Number of pages
- ix, 57 pages
- Copyright
- Copyright © 2016 Chandni Desai
- Language
- English
- Description illustrations
- color illustrations
- Description bibliographic
- Includes bibliographical references (pages 48-57).
- Public Abstract (ETD)
Fibrous growths are common occurrences in the mouth and are removed in order to be looked at under a microscope to make sure they are not cancerous. Sometimes stains are used to color the tissue and these stains are specific for certain diagnoses. Myofibroblastic proliferations (MFPs) are growths that may occur in the head and neck area and may look similar to other lesions under the microscope. Although there are specific stains that differentiate MFPs from other fibrous growths, many of these entities share the same cells: fibroblasts and myofibroblasts.
This study evaluated whether the stains used to distinguish MFPs are present in other fibrous growths thus raising the possibility that MFPs are not a separate entity but instead part of a spectrum of fibrous growths. Also, one of the stains used in this study is usually negative in MFPs but can help distinguish solitary fibrous tumor from other fibrous growths and was used to evaluate for its presence in these other fibrous growths.
The study found that the stains used to distinguish MFPs are helpful but not specific as these stains are present in other fibrous proliferations. The study also found that the stain used to distinguish solitary fibrous tumor is present in a majority of the fibrous growths in this study. Thus, it appears that it is not definitive whether MFPs are their own entity and the stain used to diagnosis solitary fibrous tumor may not be as helpful in doing so as once thought. Further studies are needed to support these findings.
- Academic Unit
- Oral Pathology, Radiology and Medicine
- Record Identifier
- 9983777291802771
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