Abstract
Background: Tumors of the oral cavity must be differentiated into benign and malignant. Rare tumors must also be considered throughout the differential diagnosis when dealing with pathologic changes in the oral mucosa. Examples of rare benign tumors within the oral cavity are solitary fibrous tumors (SFTs). In recent years, individual case reports of SFTs in the oral cavity have been published showing a rising incidence of this rare entity. Case Report: The present case report describes the occurrence of a subtype of SFT in the right buccal mucosa, the so-called giant cell angiofibroma (GCA). Histopathologically, GCA are distinguishable from SFT (NOS) by pseudovascular spaces lined by multinucleated giant cells. GCA generally shows a benign tumor behavior. The treatment of choice was surgical excision through an intraoral approach. Conclusion: To the best of our knowledge, this is one of a few reports of GCA arising in the buccal mucosa.
Many consultations in a Department for Oral and Maxillofacial surgery are made to clarify various pathological changes and/or diseases of the oral mucosa. Here, the differentiation between benign and malignant processes of the oral mucosa is particularly essential. The malignant processes of the oral mucosa include, for example, squamous cell carcinoma, malignant adenoid-cystic carcinoma originating from the small salivary glands, or mucodermoid carcinoma (1, 2). Examples of benign changes in the oral cavity are adenomas, papillomas, hemangiomas and, among other things, solitary fibrous tumors (SFTs) (3, 4). In particular, SFTs represent a rare entity. Nevertheless, increased case reports of SFTs have been published in recent years, especially those in the head and neck area (5, 6). The present case report describes another occurrence of a solitary fibrous tumor (SFT) in the oral cavity and underlines the increasing incidence of this rare entity.
Case Report
This case report describes a 47-year-old male who attended the Department of Oral and Maxillofacial Surgery with a swelling in the right buccal plane. The patient noticed the indolent swelling six months earlier. However, he noticed an intermittent feeling of pressure in this area. The patient did not notice fever, night sweats or weight loss. The only preexisting illness was arterial hypertension. During the physical examination, the right cheek was slightly enlarged. No cervical or nuchal lymph nodes could be palpated. Intraoral examination revealed a pink indolent non-displaceable nodule 2 cm in diameter in the right buccal mucosa. A sonography of the head and neck region showed no evidence of enlarged lymph nodes. The enoral mass could not be determined through sonography.
An adenoma of the small salivary glands was assumed as differential diagnosis. For further diagnostics and simultaneous therapy, the nodule was surgically removed through an intraoral approach. Here, the histopathological tissue processing revealed the rare finding of a benign SFT within the oral mucosa. Histologically, a well circumscribed predominantly cell-poor fibroblastic proliferation with broad collagen bands without specific arrangement was seen. About 30% of the tumor was more cell-rich. Furthermore, not endothelium-lined clefts were seen being demarcated by multinucleated giant cells (Figure 1A and B). More giant cells lied in the interstitial stroma. Mitoses or necrosis could not be identified. Immunohistochemical studies revealed a strong CD34 positivity of the neoplastic fibroblasts (Figure 1C). S100, alpha-actin and Desmin showed no reactivity. Ki-67 indicated a proliferative activity of <5%.
Immunohistochemical images. A) Fibroblastic proliferation with collagenous background and pseudovascular spaces lined by multinucleated giant cells, partially strung like a pearl string (HE, 400×). B) Well circumscribed predominantly cell-poor fibroblastic proliferation with broad collagen bands without specific arrangement was seen. About 30% of the tumor was more cell-rich. Furthermore, not endothelium-lined clefts were seen being demarcated by multinucleated giant cells (HE, 400×). C) Strong diffuse cytoplasmic and membranous positivity of neoplastic fibroblasts for CD34 with cutout of the non-neoplastic histiocytic cell elements (400×).
The diagnosis was that of a completely resected giant cell-rich SFT/giant cell angiofibroma (GCA) with very low risk of progression or metastasis (according to the 3- and 4-variable risk models proposed by WHO for solitary fibrous tumors). No abnormalities were found during the postoperative healing process. At the time of follow-up after four weeks, the patient was symptom-free with no evidence of recurrence. Despite the benign tumor, further follow-ups are planned in the long term. Written informed consent was obtained from the patient.
Discussion
GCA, as well as SFTs, are mesenchymal neoplasms and are generally referred to as benign tumors (7). They were first described in the area of the pleura at the beginning of the 20th century (8). However, in recent years there have also been reports of SFTs in the head and neck area (5, 6). Due to the variable localization, SFTs usually do not show any “classical” symptoms. SFTs as well as GCA show a slow, indolent growth, with subsequent displacement of neighboring structures and thus leading to functional limitations in various anatomical regions (9). In the area of the oral cavity, they can stand out as an indolent mass. In addition to persistent swelling, other symptoms in the head and neck region can also include dysesthesia in the facial region (10). In the further course, imaging methods such as sonography, computed tomography and/or magnetic resonance imaging can offer added value in diagnostics of SFT (11). Definitive diagnosis is achieved through histopathological processing. Histologically, GCA can be distinguished from SFT (NOS) by the presence of multinucleated giant cells alongside pseudovascular spaces (12).
Nevertheless, the histopathological differentiation between SFT, GCA and other benign mesenchymal neoplasms is challenging. The therapy of choice for both SFT and GCA consists of complete surgical removal of the tumor with a safety margin. Publications on recurrences of the GCA are rare. In some case reports, local recurrences were described after a period of 5 years (13). Incomplete tumor resections in particular favor the tendency to recurrences (14, 15). In general, GCA shows benign tumor behavior such as SFTs. However, due to the low number of cases of this entity, no reliable statement can be made about the long-term behavior and/or possible malignant course variants especially in the area of the oral cavity. Due to the reduced study situation, long-term clinical follow-ups are required to identify recurrences as well as potential malignant transformation.
Conclusion
GCA in the oral cavity is an absolute rarity. Nevertheless, it should be included in the differential diagnostic considerations in the case of persisting swellings in the buccal mucosa. To the best of our knowledge this case report is one of a few that shows the GCA localized within the oral cavity. Surgical tumor removal and long-term clinical follow-ups represent the therapeutic concept for this rare entity.
Footnotes
Authors’ Contributions
KOH, FB and FD treated the patient and revised the article. FD, TT and FB researched the scientific literature. AZK provided histopathological findings. FD and FB wrote the article. All Authors gave final approval for publication.
Conflicts of Interest
The Authors have no relevant financial or non-financial interests to disclose in relation to this study.
- Received January 23, 2023.
- Revision received February 2, 2023.
- Accepted February 3, 2023.
- Copyright © 2023 International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.
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