Solitary fibrous tumor of the oral cavity: the need for an extensive sampling for a correct diagnosis

Solitary fibrous tumor occurring at unusual sites: A clinico-pathological series of 31 cases with emphasis on its wide morphological spectrum

Solitary fibrous tumor (SFT) is a relatively rare mesenchymal fibroblastic tumor occurring most commonly in adults with no gender predilection. Although the pathological diagnosis of SFT is usually straightforward, some difficulties may occasionally arise mainly due to the wide morphological spectrum exhibited by this tumor. In the present paper we aimed to evaluate the unusual clinicopathological features in a series of 31 SFTs arising from parenchymal organs, superficial soft tissues and deep soft tissues. Our results emphasize that SFTs may occur anywhere, including unusual sites such as periosteum of the thoracic spine, mesorectal tissue, hepatic hilum, paravescial space, kidney and breast. Moreover, a wide morphological spectrum was observed in tumors included in our series. The most striking morphological features observed included: extensive lipomatous component, myxoid stromal changes, epithelioid cell component, metaplastic mature bone, neurofibroma-like, myxofibrosarcoma-like and pseudoalveolar-like areas. Additionally, multinucleated giant cells and sarcomatous dedifferentiation were also identified. Our paper emphasizes that SFT may occur in unusual anatomical locations and exhibits a wide morphological spectrum. Pathologists must be aware of these features to avoid confusion with other benign and malignant neoplasms that may show overlapping morphological features.

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.

Clinical management of extrapleural septal solitary fibrous tumor: A case report

Solitary fibrous tumor (SFT) is a rare neoplasm arising from the pleura, although it can sometimes affect extrapleural sites, including the head and neck. The sinonasal involvement is exceptional. Recent literature defines the SFT as a single spectrum of mesenchymal tumors, including hemangiopericytoma, which is currently considered a cellular phenotypic variant. The current case describes a rare case of a nasal septal SFT. The mass was embolized and then removed through endonasal endoscopic surgery. Histopathologic examination demonstrated positive immunoreactivity for CD34, and negative for keratin and S100 protein confirming the diagnosis of benign nasal SFT. After two years of follow-up, no relapse was observed. Diagnostic assessment of SFT requires nasal endoscopy, imaging and histopathological examination and a long time follow up is mandatory.

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.

Suprarenal solitary fibrous tumor associated with a NF1 gene mutation mimicking a kidney neoplasm: implications for surgical management

Solitary fibrous tumor (SFT) is a rare spindle cell neoplasm, usually occurring in the pleura. Pararenal SFT, mimicking an adrenal gland or renal tumor, as here described, is extremely rare. We report a case of a right suprarenal SFT, incidentally discovered by abdominal ultrasound in a 54-year-old woman carrying a point neurofibromatosis 1 (NF1) gene mutation. Preoperative diagnostic work-up was ineffective in evaluating its origin, and an open radical right nephrectomy was therefore undertaken. Immunohistochemical assay showed a positivity for CD34, CD99 and Bcl-2, so suggesting a diagnosis of SFT. According to our knowledge, the association between this type of tumor and NF1 gene mutation has never been described. In cases of pararenal tumors, a more detailed preoperative diagnosis could be useful to better plan the extension of resection, allowing, in selected cases, nephron-sparing surgery. More studies are needed to better analyze the relationship between NF1 gene mutation and SFT.

Solitary fibrous tumor of the soft palate: A report of two cases

Solitary fibrous tumors (SFTs) are a unique group of mesenchymal neoplasms of fibroblastic or myofibroblastic origin and are extremely rare in the oral cavity. The present study reported two additional cases of SFTs in the soft palate, along with the computed tomography characteristics, which demonstrated well-circumscribed soft tissue lesions with marked and homogenous enhancement. Following wide resection, one of the cases showed certain malignant pathological characteristics, including infiltration of mucinous gland, hypercellularity, nuclear atypia and weak positive staining for S-100. In our experience, SFTs should be considered as a differential diagnosis when a well-circumscribed and solid mass in the soft palate is identified.

Solitary fibrous tumor with entrapment of minor salivary gland tissue: an unusual presentation that requires exclusion of pleomorphic adenoma

We report two unusual cases of solitary fibrous tumor (SFT) of minor salivary glands that microscopically mimicked pleomorphic adenoma. One of these lesions presented in the retromolar region and the other in the buccal mucosa. The microscopic features of these two tumors and their intimate relationship with regional mucous minor salivary glands posed a diagnostic challenge. Awareness of the morphological diversity of SFT coupled to a judicious use of appropriate immunohistochemical probes should prove valuable to accurately segregate SFT from pleomorphic adenoma.

[Solitary fibrous tumour of the smooth palate]

The solid fibrous solitary tumour of the oral cavity is an extremely rare entity. It is also of complicated diagnosis because of its extensive morphologic diversity (especially when there is a small amount of biopsied tissue) and because of its similarity to many mesenchymal injuries, mostly with hemangiopericytoma. The prognosis is reserved because of the few cases reported, mainly depending on tumour location and size.

Solitary fibrous tumor of the oral cavity: clinicopathologic and immunohistochemical study of 21 cases

We describe clinical, morphologic, and immunohistochemical features of 21 cases of solitary fibrous tumor presenting in the oral cavity. There were 9 male and 12 female patients with a median age of 51 years (range 37-83). The most common locations included the buccal mucosa (the most common site), lip, maxillary or mandibular vestibule and tongue. Histopathologic examination showed well-circumscribed tumors with two well-defined patterns: the classic pattern with densely cellular areas alternating with hypocellular areas in a variably collagenous, vascular stroma and a more uniformly sclerotic pattern with only subtle classic areas. The spindle-shaped neoplastic cells consistently showed immunoreactivity for antibodies directed against CD34. Five of nineteen cases (26%) were reactive for CD99 and 19 of 19 for Bcl-2. Follow-up information was available in 17 cases and averaged 54 months, with no evidence of recurrence or metastasis in any of these patients. Awareness that solitary fibrous tumor may present in the oral cavity is important so that confusion with other spindle cell neoplasms can be avoided. We also briefly describe the differential diagnosis and compare this series, the largest single series of intraoral SFT, to cases previously reported in the literature.

An aggressive solitary fibrous tumor with evidence of malignancy: a rare case report

Solitary fibrous tumor (SFT) is rare mesenchymal neoplasm that has been originally and most often documented in the pleura. Recently, the ubiquitous nature of the SFT has been recognized with reports of involvement of numerous sites all over the body, i.e, upper respiratory tract, breast, somatic tissue, mediastinum, head, and neck, etc. The diagnosis of SFT still remains an enigma in our field. Furthermore, malignant SFT is extremely rare and only two cases have been reported in the oral cavity till date. Here, we present a rare case report of an aggressive solitary fibrous tumor which presented as a palatal mass and extended throughout the middle cranial fossa and exhibited features of malignancy.