Solitary fibrous tumour of the oral cavity: An update

Solitary fibrous tumors of the oral and maxillofacial region: a case series from a single-center

BACKGROUND

Solitary fibrous tumor (SFT) is a rare mesenchymal lesion that has a wide anatomic distribution. However, this lesion rarely occurs in the oral or maxillofacial region.

METHODS

A retrospective review was performed to evaluate the clinical symptoms, radiological images, pathology and immunohistochemistry results of 9 patients with SFTs treated between January 2015 to April 2024 in our institute. Surgical tumor resection was administered to all patients. Follow-up for these patients spanned until the conclusion of April 2024.

RESULTS

The series contained 3 males and 6 females, with the mean age 50.6 years (range: 25 to 73 years). The tumors were distributed at six different sites, including the tongue, submandibular region, cheek, sublingual gland, mandible, and hard palate. Clinically, the mass grew gradually and usually without obvious clinical symptoms. On imaging examination, the boundaries of all the tumors were clear, except for one patient with a mandibular tumor. Surgical excision was performed in all patients. Histological characteristics and positive immunostaining for STAT6, CD99, CD34 and Bcl-2 were the most important criteria for a final diagnosis. All tumors were positive for CD34 and Bcl-2. Only one tumor was negative for STAT6. While CD99 was negative in one case and weakly positive in two cases. All patients had no local recurrence during the follow-up period ranging from 1 to 100 months (mean 41.4 months).

CONCLUSIONS

Benign SFTs occurring in the oral and maxillofacial region are rare, and surgery is the primary treatment for this tumor. It usually presents as a distinctly bordered heterogeneous mass on imaging. The tumors can compress surrounding bone tissue leading to bone resorption, and in rare cases, it may exhibit invasive resorption. SFTs should be included in the differential diagnosis of lesions in the oral and maxillofacial region.

Oral solitary fibrous tumors: A collaborative clinicopathologic study of 19 cases

OBJECTIVE

To report the clinicopathologic features of 19 oral solitary fibrous tumors (SFTs).

METHODS

Clinical data were collected from the records of seven pathology services. All cases were re-evaluated by HE staining and confirmed by immunohistochemistry.

RESULTS

The series comprised 11 females (57.9%) and 8 males (42.1%), with a mean age of 47.3 ± 14.7 years (range: 22-71 years) and a 1.3:1 female-to-male ratio. Most tumors affected the buccal mucosa (n = 7; 36.8%) and presented clinically as an asymptomatic solitary submucosal well-circumscribed nodule with coloration similar to the oral mucosa. Morphologically, most SFTs (n = 10; 52.6%) exhibited a classic hybrid pattern characterized by a well-circumscribed proliferation of densely cellular areas alternating with hypocellular areas in a variably collagenous vascular stroma. Remnants of accessory salivary glands were observed in two cases (n = 2; 10.5%). All tumors were positive for STAT6 and CD34 (n = 19; 100%). Outcome information was available from 6 patients (31.6%), with clinical follow-up ranging from 6 to 24 months (mean ± SD, 9.5 ± 6.8 months), and none developed local recurrence.

CONCLUSIONS

Oral SFTs are rare and often clinically misdiagnosed. Pathologists should consider SFT in the differential diagnosis of oral spindle cell tumors. Accurate diagnosis requires careful morphological evaluation supported by immunohistochemical analysis.

Atypical Tongue Abscesses Mimicking Submucosal Malignancies: A Review of the Literature Focusing on Diagnostic Challenges

Tongue abscesses are rare conditions that usually follow mucosal disruption due to mechanical trauma or foreign body impaction. They typically manifest abruptly as a rapidly growing, hard mass or swelling in the context of tongue muscles; the patient frequently complains of pain, difficulties in swallowing or speaking, and fever. Nonetheless, the features of its presentation, together with accurate clinical evaluation, blood tests, and appropriate imaging tests, are usually sufficient to easily discern a tongue abscess from a malignancy. However, in rare cases, they may occur with slowly progressing and subtle symptoms, nuanced objective and laboratory findings, and inconclusive radiological evidence, leading to difficult differential diagnosis with submucosal malignancy. Herein, we review the literature, available on Pubmed, Embase, and Scopus, on publications reporting tongue abscesses, with atypical presentation suggesting an oral tumor. Our review confirms that tongue abscesses may manifest as a slowly growing and moderately painful swelling without purulent discharge and minimal mucosal inflammation; in this case, they may constitute an actual diagnostic challenge with potentially severe impact on correct management. Atypical tongue abscesses must therefore be considered in the differential diagnosis of tongue malignancy with submucosal extension, even when other diagnostic elements suggest a neoplasia; in this case, a deep biopsy under general anesthesia is essential for differential diagnosis, and simultaneous drainage of the necrotic and abscessual material may resolve the condition.

Diagnostics and Treatment of Extrameningeal Solitary Fibrous Tumors

Solitary fibrous tumors (SFT) are rare mesenchymal neoplasms that account for less than 2% of all soft tissue masses. In the latest WHO 2020 Classification of Soft Tissue Tumors, extrameningeal SFT was listed as intermediate (rarely metastasizing) or malignant neoplasms. Due to the lack of characteristic clinical features, their diagnosis and treatment remain challenging. The pathogenesis of SFT is often associated with the presence of fusions of the NAB2-STAT6 gene on the 12q13 chromosome. Cytoplasmic CD34 positive staining is considerably characteristic for most SFTs; less frequently, factor XII, vimentin, bcl-2, and CD99 are present. A key factor in the diagnosis is the prevalent nuclear location of STAT6 expression. Radical resection is the mainstay of localized SFTs. In the case of unresectable disease, only radiotherapy or radio-chemotherapy may significantly ensure long-term local control of primary and metastatic lesions. To date, no practical guidelines have been published for the treatment of advanced or metastatic disease. Classical anthracycline-based chemotherapy is applicable. The latest studies suggest that antiangiogenic therapies should be considered after first-line treatment. Other drugs, such as imatinib, figitumumab, axitinib, and eribulin, are also being tested. Definitive radiotherapy appears to be a promising therapeutic modality. Since standards for the treatment of advanced and metastatic diseases are not available, further investigation of novel agents is necessary.

Primary angiomatoid fibrous histiocytoma of the mandible with EWSR1-ATF1 fusion in an adult patient: case report and review of literature

OBJECTIVE

We report our diagnosis of a rare case of primary angiomatoid fibrous histiocytoma in the mandible of a 42-year-old male using next-generation sequencing to detect disease-specific EWSR1-ATF1 fusion.

STUDY DESIGN

After the initial cone beam computerized tomography scan and reconstruction, we performed immunohistochemical staining and fluorescence in situ hybridization analysis on tissue samples to detect EWSR1 gene rearrangement. For the final diagnosis, we performed next-generation sequencing to detect disease-specific EWSR1-ATF1 fusion.

RESULTS

FISH analysis showed approximately 55% of tumor cells with mostly isolated red signals, as well as several split red-green signals, indicating the presence of EWSR1 gene rearrangement. Next-generation sequencing analysis identified an EWSR1 exon9-ATF1 exon4 fusion, a diagnostic biomarker of angiomatoid fibrous histiocytoma (AFH). Based on the findings, we diagnosed primary AFH derived from the mandible.

CONCLUSIONS

Next-generation sequencing is a powerful methodology for detecting disease-specific EWSR1-ATF1 fusion and diagnosing primary angiomatoid fibrous histiocytoma.

Metastasis of a Solitary Fibrous Tumor in the Mandible: A Case Report

BACKGROUND/AIM

The solitary fibrous tumor (SFT) is a mesenchymal neoplasm and belongs to the group of soft tissue sarcomas. The SFT is characterized by indolent, slowly progressive growth and manifests itself clinically by compression of neighboring structures. The treatment of choice is surgical removal of the tumor. In advanced stages, there is also the possibility of chemotherapy, systemic therapy, or immunotherapy, as well as radiotherapy. Depending on their location and severity, SFTs show different recurrence rates and survival functions.

CASE REPORT

The present case report shows an extremely rare localization of a low-risk SFT in the floor of the mouth. Despite complete surgical removal of the SFT, the patient showed a metastasis of the SFT in the mandible two years postoperatively. Therefore, this case report shows that even a low-risk SFT in the localized stage can metastasize despite of total surgical removal. Consequently, SFTs of the head and neck region require close clinical and imaging follow-up.

CONCLUSION

Although the localization of the SFT in the oral cavity is a rarity, this entity should be included in the differential diagnosis in the case of long-term space-occupying processes in the head and neck region. This report is the first regarding metastasis of a SFT to the mandible.

Solitary fibrous tumor of the tongue

Solitary fibrous tumor (SFT) is a benign mesenchymal neoplasm originally described in pleura with a rare presentation in the oral cavity. Herein, we report a case of a 28-year-old male patient who presented an asymptomatic slow-growing mass in the anterior part of the tongue. Intraoral examination revealed a well-circumscribed mass covered by normal mucosa with a fibrous consistency. Due to non-specific clinical findings, the initial diagnostic hypotheses include benign submucosal neoplasms such as leiomyoma, neurofibroma, SFT, and others. An excisional biopsy was performed. Microscopically, the tumor was surrounded by a thick fibrous capsule; hypo and hypercellular areas were arranged in a storiform pattern with a stroma formed by collagen and abundant vascularization. Tumor cells showed immunopositivity for CD34 and STAT-6 and no expression of CD99, AML, S-100, and Ki-67. According to these findings, the diagnosis of SFT was established. After 24 months, the patient is asymptomatic and has no evidence of recurrence. Although oral involvement is rare, SFT should be included in the differential diagnosis of oral submucosal lesions.

Malignant solitary fibrous tumor of the floor of the mouth in a 71-year-old male: A case report

Solitary fibrous tumors are rare mesenchymal tumors originally described in the pleura that infrequently metastasize. We present a 71-year-old male complaining of hemoptysis and a mass with the characteristic appearance of a hemangioma in the floor of the mouth. The mass had nonspecific imaging features on CT and MRI. After unsuccessful fine needle aspiration, surgical excision and biopsy with histological analysis revealed a solitary fibrous tumor, high risk variant. CT Imaging and lymph node biopsy showed gross total resection and no metastatic adenopathy. Given the high risk for malignancy, the patient received adjuvant radiation without subsequent clinical or imaging signs of recurrence. This case report demonstrates the presentation of this rare entity that can often be confused with other tumors in this region, given its nonspecific clinical and imaging findings.

Histopathological findings and immunohistochemical expression of the stem cell markers CD44, ALDH1, Bmi-1, and Nanog in oral solitary fibrous tumors

OBJECTIVES

The aim of this study was to evaluate the histomorphologic presentation and the expression of stem cell-related markers in a series of oral solitary fibrous tumors (SFTs).

STUDY DESIGN

Histopathological variables and the expression of the standard stem cell markers CD34 and CD99, used for SFT diagnosis, as well as STAT6 were evaluated in 13 oral SFTs. The expression of the cancer stem cell markers CD44, ALDH1, Bmi-1, and Nanog and the tumor suppressor gene p16^Ink4a were also investigated.

RESULTS

The majority of oral SFTs were circumscribed and characterized by a proliferation of spindle cells arranged in a hyalinized stroma. Only 2 oral SFTs showed >4 mitoses/10 high-power fields. Hypercellularity as well as nuclear and cellular pleomorphism were classified as low and moderate in most of the oral SFTs. All oral SFTs were positive for CD34, STAT6, CD44, ALDH1, Bmi-1, and p16^Ink4a. CD99 and Nanog expression was observed in 11 and 10 oral SFT cases, respectively.

CONCLUSION

We suggest that STAT6 and ALDH1 have relevant diagnostic value. The expression of CD44, ALDH1, Bmi-1, and Nanog, which is observed in cancer stem cells, may confer advantages to oral SFT cells.

Oral Solitary Fibrous Tumor: A Retrospective Clinico-Pathological Study and Long-Term Follow-Up

Background and Objectives: This was a retrospective single-center study to analyze and describe the clinical and histological features of all cases of oral solitary fibrous tumor (SFT). Study design: the study included all consecutive cases of oral SFT diagnosed between 2008-2018 at a single tertiary center. Materials and Methods: Clinical data was retrieved from medical charts. The diagnosis of oral SFT was based upon the morphologic features of the lesions, in routine hematoxylin and eosin (H&E) stained sections and confirmed by immunohistochemical analyses including CD34, CD99, Bcl2, and stains for STAT6. Results: Seven cases of oral SFT were found. Of these, three (42%) were in males and four (58%) in females. The age range was 24-63 years (mean 47 ± 13). Four (58%) lesions were located in the buccal mucosa, two (28%) in the labial mucosa and one (14%) on the floor of the mouth. The diameter ranged between 3-50 mm (mean 22 ± 14 mm). All patients were treated with local excision. Follow-up periods were between 2-74 months (mean 41 ± 27). No recurrences were reported. Conclusions: We present a series of oral SFT, which were all non-aggressive in presentation and did not recur after conservative surgery (local excision) over a relatively long follow-up period.

Desmoplastic fibroma of the Mandible with unusual histopathological features

Desmoplastic fibroma (DF) is a rare myofibroblastic primary tumor of bone that histologically and biologically mimics the extra-abdominal desmoid tumor of soft tissue. The surgical management of this tumor has been a matter of controversy and its recurrence has been a matter of clinical relevance. In this case report, we describe an unusual case of DF in a 15-year-old male patient who presented with a slow-growing mass in the right posterior mandibular region of 2 years duration. The presence of areas mimicking Giant cell angiofibroma (GCA) is the highlight of the case. The possibility of misdiagnoses is more in early lesions since the available literature shows that immunohistochemistry (IHC) is not of much benefit while differentiating DFs from other spindle cell lesions.

Inflammatory Variant of Atypical Lipomatous Tumor/Well-Differentiated Liposarcoma of the Buccal Mucosa: An Overview and Case Report with a 10-Year Follow-Up

Liposarcomas of the oral cavity are rare. Those originating in the buccal mucosa cause challenging diagnostic and therapeutic issues since less than 40 cases of liposarcomas of the buccal mucosa and cheek have been reported in the worldwide literature. Herein, we present a case of atypical lipomatous tumor/well-differentiated liposarcoma affecting a 45-year-old female patient. Ultrasonography and magnetic resonance imaging confirmed a well-defined mass located in the right buccal mucosa, extending to the submucosal layers of the cheek. Histopathologically, a well-differentiated fatty neoplasm with presence of prominent stromal inflammatory cells was observed. Multifocally scattered bizarre hyperchromatic stromal cells, some of which multinucleated, were also observed. An immunohistochemical panel comprising vimentin, S-100, CD10, CD34, CD20, CD3, CD68, CD138, MDM2, Ki-67, and P53 was employed to better characterize the lesion. A local recurrence event occurred during a 10-year follow-up period. Surgical resection was performed during both episodes. We also provided an overview of demographic and clinicopathological characteristics, immunohistochemical features, imaging findings, and the differential diagnosis of liposarcoma of the oral cavity. Knowledge of the etiopathological and clinical aspects of this rare neoplasm is fundamental in order to rule out other conditions, including lipomatous lesions that affect the buccal mucosa.

Oral focal mucinosis: A multi-institutional study and literature review

BACKGROUND

Oral focal mucinosis (OFM) is a rare benign condition of unknown etiology, considered the oral counterpart of cutaneous focal mucinosis. We report the clinicopathologic features of 21 cases of OFM in conjunction with a review of the literature.

METHODS

Clinical data were collected from the records of five oral and maxillofacial pathology services. All cases were evaluated by hematoxylin and eosin staining, histochemistry, and immunohistochemistry (vimentin, S-100, α-SMA, CD34, and mast cell).

RESULTS

The series comprised 14 females (66.7%) and seven males (33.3%), with a mean age of 48.2 ± 20.7 years (range: 8-77 years) and a 2:1 female-to-male ratio. Most of the lesions affected the gingiva (n = 6, 28.6%) and presented clinically as asymptomatic sessile or pedunculated nodules with fibrous or hyperplasic appearance. All cases were negative for S-100 protein, CD34, and α-SMA and positive for Alcian blue staining. Conservative surgical excision was the treatment in all cases, and there was only one recurrence.

CONCLUSION

OFM is a rare benign disorder that is often clinically misdiagnosed as reactive lesions or benign proliferative processes. Dermatologists and pathologists should consider OFM in the differential diagnosis of soft tissue lesions in the oral cavity, mainly located in the gingiva.

Clinicopathologic Analysis of Oral and Maxillofacial Solitary Fibrous Tumor

OBJECTIVES

The aim of this systematic review was to provide an overview of the oral and maxillofacial solitary fibrous tumor (SFT) in order to determine its clinicopathologic characteristics and biological behavior.

METHODS

We conducted a systematic review in May 2019 in multiple databases. Cases diagnosed as SFT in the oral cavity and maxillofacial complex were included.

RESULTS

Seventy-three published articles were included in our systematic review, corresponding to a total of 154 cases. SFT showed a slight female predilection (53.2%), and the cheek mucosa/cheek, tongue, and palate were the most affected anatomical sites. The mean size of SFT in the oral cavity and maxillofacial region at diagnosis was 1.4 cm. Histologic features of malignancy by morphologic analysis (P < .001) were significantly associated with a larger tumor size. Surgical excision was the most frequent therapeutic modality. Recurrence and metastasis were uncommon findings in our sample.

CONCLUSIONS

Histologic features of malignancy can be important parameters of tumor behavior. Adequate surgical treatment and long-term follow-up are required for these cases.