Clinicopathologic and immunohistochemical features of five new cases of solitary fibrous tumor of the oral cavity

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.

Orbital solitary fibrous tumours: clinicopathological characteristics and recurrence prediction

BACKGROUND

SFTs are thought to have an unpredictable clinical course and currently have no recognized prognostic criterion. Our study aimed to determine the relationship between clinicopathological characteristics and the prognosis of patients with orbital SFTs.

METHODS

The clinicopathological features of these patients were extracted from clinical records. The relationships between these features and prognosis were analysed.

RESULTS

The positive rates of CD34, CD99, Blc2, and STAT6 expression were 90.3%, 90.3%, 83.9%, and 100%, respectively. The tumour recurrence rate was 38.7%. A higher recurrence rate was observed in patients with Ki67 index ≥ 5 (56.25% vs. 20%, P = 0.038).

CONCLUSION

A Ki67 index ≥ 5 was an effective parameter for predicting tumour recurrence of orbital SFTs. Close follow-up is needed for these patients.

A Rare Case of a Solitary Fibrous Tumor in a Child, Presenting as a Congenital Mass, Displaying NAB2ex4::STAT6ex2 Gene Fusion with an Incidental Ganglioneuroblastoma

A solitary fibrous tumor (SFT) is a ubiquitous tumor that occurs across all ages. It is rarely reported in pediatric patients, especially as a congenital mass. A 1 year 7-month old male child presented with a slow-growing gluteal mass since birth along with a recent episode of bleeding. Magnetic resonance imaging (MRI) showed a well-defined, T1-hypointense and T2-hyperintense mass in the skin and the subcutaneous plane. Subsequently, he underwent a surgical resection that revealed a 5.7 cm-sized fleshy mass. On histopathologic examination, there was a fairly well-circumscribed, cellular spindle cell tumor, with cells arranged in intersecting fascicles and hemangiopericytomatous pattern with areas of hemorrhage and fibrinoid necrosis. Cells revealed mild nuclear atypia. Mitotic figures were up to 8/10 hpf. Immunohistochemically, the tumor cells were diffusely positive for CD34 and STAT6. Furthermore, the tumor revealed NAB2 exon 4:: STAT6 exon 2 fusion by RT-PCR and Sanger sequencing. Post-excision, during follow-up, the patient developed an adrenal mass that was histopathologically proven as a neuroblastic tumor, not further specified on biopsy and finally as ganglioneuroblastoma, intermixed type on excision. This constitutes one of the rare cases of SFT in a pediatric patient, presenting as a congenital mass, confirmed by STAT6 immunostaining and further, molecular testing. A review of literature of similar cases, including treatment-related implications, is presented.

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.

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.

Transoral surgical approach to solitary fibrous tumors in buccal space with infratemporal tumor extension: A case report

A solitary fibrous tumour (SFT) is a rare spindle-cell neoplasm of mesenchymal origin usually located in the pleura. It has been recently described as occurring in various head and neck sites, including the oral cavity. The purpose of this article is to report a case of SFT originating in the buccal space and extending into the infratemporal space treated by means of transoral approach surgery. A 25-year-old female patient reported to the Department of Oral and Maxillofacial Surgery, Universitas Airlangga Hospital, chiefly complaining of a painless lump in the left cheek which had been present for nine months. The diagnosis was arrived at on the basis of a combination of clinical investigation, imaging studies and histopathological examination (biopsy). The surgical approach involved transoral incision through the buccal mucosa. An SFT of buccal space may extend to nearby structures producing the anatomical challenge of removal through a transoral approach. Excisional biopsy involving a transoral approach is, nevertheless, considered appropriate because it produces an attractive aesthetic appearance, reduces morbidity from nerve/ vascular/ gland injury and promotes more effective healing. Key words:Solitary fibrous tumor, buccal space, infratemporal space, transoral approach.

Solitary Fibrous Tumor/Hemangiopericytoma of Spinal Cord: A Retrospective Single-Center Study of 16 Cases

OBJECTIVE

In this study, we retrospectively reviewed our experience in the surgical management of solitary fibrous tumor (SFT)/hemangiopericytomas (HPCs) of the spinal cord.

METHODS

Sixteen patients with SFT/HPCs of the spinal cord were enrolled in this study. Data on clinical presentation, radiologic findings, histopathologic features, surgical treatment, adjuvant therapy, and prognosis were retrospectively reviewed. Kaplan-Meier curves and log-rank tests were used to identify the prognostic factors for recurrence and overall survival (OS).

RESULTS

Our series included 6 men and 10 women, with a male/female ratio of 1:1.7. Magnetic resonance imaging (MRI) showed slightly hyperintense lesions on T2-weighted images for all 16 patients. All tumors showed positive immunohistochemical staining for signal transducer and activator of transcription 6. Statistical analysis of clinical data showed that age, gender, tumor location, tumor size, medullary compartment location, and Ki-67 index were not associated with recurrence and OS (P > 0.05). However, World Health Organization grade III was significantly associated with recurrence (P < 0.01). Gross total resection (GTR) and postoperative radiotherapy significantly reduced recurrence (P < 0.01 and P < 0.05), but only GTR showed remarkable benefits to improve OS (P < 0.05).

CONCLUSIONS

SFT/HPCs of spinal cord are rare neoplasms with a propensity to recur. Hyperintensity on T2-weighted magnetic resonance imaging combined with positive immunohistochemical staining for signal transducer and activator of transcription 6 are important clues for classification and differentiation of these tumors. The extent of resection, World Health Organization grade, and postoperative radiotherapy might be predictive factors for recurrence. Complete tumor resection should be sought whenever possible, and adjuvant radiotherapy is recommended after surgical resection. Moreover, regular and long-term follow-up is mandatory to monitor recurrence.

Solitary fibrous tumor of the floor of the mouth

BACKGROUND

A solitary fibrous tumor (SFT) of the oral cavity is an extremely rare entity. Its diagnosis is complicated because of its diverse morphology and similarity to other mesenchymal diseases.

CASE REPORT

A rare case of SFT involving floor of the mouth is presented. The tumor was well circumscribed and almost spherical, measuring approximately 3 cm in diameter. Patient was submitted to biopsy and histopathologic examination showed a tumor composed of spindle to epithelioid cells showing pale to eosinophilic cytoplasm, oval or elongated nuclei with inconspicuous nucleoli. Tumor cells showed strong positivity for CD34, vimentin and Bcl-2. SFTs may present as a diagnostic challenge. The patient was followed for 8 years without recurrences.

RESULTS

SFT is an uncommon disease in maxillofacial region; however it should be considered in the differential diagnosis of spindle cell neoplasms with oral manifestation. Only a few cases have been reported in the floor of mouth. We describe a new case of SFT arising at this location. Key words:Solitary fibrous tumors, mouth floor, oral diagnosis.

STAT6 Reliably Distinguishes Solitary Fibrous Tumors from Myofibromas

Solitary fibrous tumors (SFT) and myofibromas (MF) historically have belonged to the same morphologic spectrum and have been lumped together under the nonspecific umbrella term, "hemangiopericytoma" along with other pericytic/myoid tumors. While current evidence shows clear distinction between the two entities, they frequently remain in the same histopathologic differential diagnosis. This diagnostic dilemma especially is common for smaller incisional biopsies from the oral cavity. STAT6 immunohistochemistry (IHC) recently was established as a reliable method to detect solitary fibrous tumor; however, the literature is sparse regarding STAT6 reactivity in MFs. The authors report ten new cases of oral solitary fibrous tumor, discuss histopathologic similarities and differences between the two tumors, and list respective STAT6 IHC expressivity. After IRB approval, 10 cases diagnosed as SFT and 24 cases of MF were collected from the University of Florida Oral and Maxillofacial Pathology Biopsy Service between the years 1994 and 2016. The original hematoxylin and eosin slides and related IHC were reviewed. IHC with STAT6 antibody was performed on all 34 samples, and the findings were analyzed. All cases were from the oral cavity or perioral regions. 10/10 SFTs expressed STAT6 nuclear reactivity, while no cases of MF showed nuclear expression of STAT6. STAT6 is a dependable marker to differentiate SFTs from MFs.

An Unusual Clinical Presentation of Solitary Fibrous Tumor in the Oral Cavity

Solitary fibrous tumor is a rare neoplasm of mesenchymal origin that usually affects the pleura. This rarity becomes more relevant in the oral cavity since the clinical features are nonspecific. A 66-year-old female patient presented with a 3-month history of a swelling in the floor of the mouth, measuring 2 cm in greatest diameter, and pain symptomatology. Occlusal and panoramic radiographs showed no bone involvement. Ultrasonography of the submandibular and parotid salivary glands revealed normal morphology, dimensions, and echogenicity. During this exam, a nodular image of low echogenicity measuring about 2.7 × 1.8 cm was detected. An excisional biopsy was performed and histopathological analysis revealed a well-defined tumor-like lesion with alternation between hypercellular areas without a defined pattern and hypocellular areas. On immunohistochemistry, the tumor was positive for CD34 and CD99 and negative for α-SMA, S-100, and bcl-2. Combining the histopathological and immunohistochemical features, the diagnosis was solitary fibrous tumor. The patient is under periodical clinical follow-up and shows no signs of recurrence 7 months after surgical excision of the tumor. The combination of clinical-pathological and immunohistochemical features is necessary for the diagnosis.