3D-guided cadaveric fibula reconstruction for pediatric infratemporal solitary fibrous tumor

We aimed to report a case of orbital solitary fibrous tumour (SFT) in a child and to review the relevant literature. We describe an SFT in a 13-year-old boy with a 1-month history of painless proptosis in the left eye. Magnetic resonance imaging revealed a well circumscribed mass filling most of the left intraconal orbit. The lesion was excised and histopathological examination revealed a malignant SFT. Postoperative follow-up for 18 months was uneventful. Malignant SFT of the orbit should be included in the differential diagnosis of paediatric orbital tumours. Complete surgical excision remains the preferred method of management and the longterm prognosis is guarded.

Solitary fibrous tumors (SFTs) most commonly occur in the pleura, but may also occur in the central nervous system (CNS). Among the numerous cases of CNS SFT that have been reported, totaling to more than 220 cases, the myxoid SFT of the CNS has been the least recognized and most misleading subtype.1 Differential diagnosis from chordoid or myxo-chordoid meningioma, myxoid peripheral nerve sheath tumor, metastatic or primary low-grade fibromyxoid sarcoma, primary intracranial myxoma, and metastatic tumor from a cardiac primary tumor is therefore necessary. Here, we present a case of a myxoid SFT located in the tentorium cerebelli. A 45-year-old woman presented with headache, general weakness, and impaired vision. A magnetic resonance imaging scan revealed a lunulating, contoured, enhancing mass measuring 7.0×6.0×2.0 cm with hemorrhagic foci, located in the right posterior parietal and temporooccipital convexities. Under the diagnosis of meningioma, open craniotomy, right parietotemporooccipital, and subtotal tumor removal was performed. Upon observation, many firm, rubbery, and bosselated tumor fragments, tan-white in color, were identified. The cut surface was relatively homogeneous, with a whitish fibrotic appearance and softer areas of gelatinous myxoid change, approximately 50%. Necrotic areas were not observed. Microscopic examination revealed a predominantly hypocellular area in the myxoid stroma, intervening with foci of a morphologically typical, densely cellular SFT with spindle cells and collagenous stroma (Fig. 1). In the hypocellular and myxoid areas, a proliferation of cytologically bland spindled cells was randomly arranged in a loose myxoid matrix, forming interconnecting strands, and resulting in degeneration. The neoplastic cells had oval to elongated nuclei, with evenly distributed chromatin, inconspicuous nucleoli, and scant pale cytoplasm. Immunohistochemically, the tumor cells showed a strong expression of CD34, vimentin, Bcl2 and CD99, but were negative for epithelial membrane antigen (EMA), pan-cytokeratin, and glial fibrillary acidic protein (GFAP). The Ki-67 labeling index was lower than 4%. On the basis of these findings, the final diagnosis was myxoid SFT. Fig. 1 Histologic findings. Myxoid stroma with focal ropy collagen in a rich vascularized tumor (A), moderately cellular area exhibiting spindle cells and collagenous stroma (B), and strong immunoreactivity for CD34 (C). Myxoid SFT of the CNS is an extremely rare tumor and differential diagnosis may be difficult to achieve owing to confusion with several other myxoid spindle cell neoplasms. Indeed, myxoid SFT of the CNS must be differentiated from chordoid or myxo-chordoid meningioma, myxoid peripheral nerve sheath tumor, metastatic or primary low-grade fibromyxoid sarcoma, primary intracranial myxoma, meningeal hemangiopericytoma and metastatic tumor from a cardiac primary. Immunohistochemistry has proven to be a useful tool in attaining an accurate diagnosis. SFT of the CNS commonly shows strong positivity for CD34, Bcl2, and vimentin, but is negative for S-100 protein, GFAP, and EMA. Negativity for S-100 rules out chordoid or myxo-chordoid meningioma (vimentin+/EMA+/CD34+/S-100-), myxoid peripheral nerve sheath tumor (vimentin+/S-100+/EMA-/CD34-), metastatic or primary low-grade fibromyxoid sarcoma, and primary intracranial myxoma. Positivity for CD34 and Bcl2 may rule out the meningeal hemangiopericytoma (vimentin+/EMA-/CD34-/Bcl2-).2 Through clinical correlation, metastatic cardiac myxoma may be easily suspected. The histogenesis of SFT is still unclear; however, tumor cells were shown to share similar histological features with fibroblasts. Microscopically, there are 3 common elements that appear in SFTs: spindle cells, a dense collagenous matrix, and prominent blood vessels.1 Spindle cells have oval nuclei with scant cytoplasm, and the cell borders are unclear. They may arrange into fascicles with no specific direction, creating a swirling pattern. The collagenous area is variable in size, and takes the form of ropy collagen. Cell density also varies, with hypercellular and hypocellular areas.3 Our case also shows a predominantly hypocellular area with myxoid stroma, and a hypercellular area with collagenous stroma. When fibrous tumors with myxoid nature involve the CNS, proper immunostaining and histologic differentiation should be done for differential diagnosis.

Objective: To investigate the clinicopathological characteristics, immunophenotypes, and diagnostic and differential diagnostic features of myxoid solitary fibrous tumor (SFT). Methods: Seven cases of myxoid SFT were collected from the archives of Zhejiang Provincial People's Hospital from January 2014 to December 2019. The clinical features, histomorphology, immunohistochemistry, molecular genetics and prognosis were analyzed and the relevant literature was reviewed. Results: There were three male and four female patients ranging from 32 to 67 years. Locations included the pleura (three cases), pelvic cavity, vagina, parotid gland, and nasal cavity(one each). Tumor size ranged from 2.7 to 13.5 cm. Histologically, all cases were characterized predominantly by the presence of myxoid stroma comprising 55% to 90% of the tumor (mean 72%). The tumors were composed of predominantly stellated, spindled or ovoid cells disposed haphazardly, in loose fascicles, or in anastomosing strands imparting a microcystic/reticular appearance in a extensively myxoid, richly vascularized stroma. Staghorn-shaped branching vessels and thin strands of collagen were commonly seen between tumors cells amidst the myxoid background. These myxoid areas were punctuated by small cellular areas showing diagnostic features of classical SFT, which were present in all seven cases. Areas showing giant cell angifibroma-like change were noted in 2 cases and focal lipomatous metaplasia was identified in 1 case. Atypical features suggestive of aggressive behavior were present in 2 cases and in one of the cases myxoid SFT with high-grade sarcomatous overgrowth was noted. Immunohistochemically, tumor cells in all cases stained positively for STAT6 and CD34. Polymerase chain reaction technique showed in both the examined cases the characteristic NAB2ex4-STAT6ex2 fusion gene. According to the Demicco's risk assessment model, four cases were classfied as low, one was classified as moderate and 2 was classified as high. Follow-up information was obtained in 4 cases. One tumor recurred 3 times within 48 months after operation, and the other 3 cases had no tumor recurrence and metastasis. Conclusions: Myxoid SFT represents a rare morphologic variant of SFT with biological behaviors ranging from indolent to aggressive. Myxoid SFT should be included in the differential diagnostic spectrums of soft tissue tumors with significantly myxoid change. Carefully searching for the typical SFT histomorphology with the use of immunohistochemistry and if necessary, molecularly testing for NAB2-STAT6 fusion can help to distinguish myxoid SFT from its many mimickers.

While focal myxoid areas are occasionally observed in solitary fibrous tumors, neoplasms of this type exhibiting extensive myxoid change are considered exceedingly uncommon. Due to their rarity, the biologic behavior of myxoid solitary fibrous tumor has not been determined. Three cases of myxoid solitary fibrous tumor are described in order to better characterize the clinical and pathologic features of this uncommon variant of solitary fibrous tumor. The tumors occurred in one man and two women, with ages of 37, 47, and 58 years, respectively. Sites of involvement included the retroperitoneum, pelvis, and soft tissue of the neck. Histologically, all cases were characterized predominantly by the presence of myxoid stroma comprising 70% to 100% of the tumor. The tumor cells were predominantly spindled in all cases, and arranged randomly, in loose fascicles, or in anastomosing strands imparting a microcystic/reticular appearance. The lesional cells had a bland cytologic appearance and low mitotic count. All tumors lacked necrosis and areas of increased cellularity. By immunohistochemistry, all cases were positive for CD34, CD99, and bcl-2, and negative for keratin, epithelial membrane antigen, desmin, actin, smooth muscle actin, and S-100 protein. To date, all cases have followed a benign course without evidence of recurrence or metastasis with a follow-up duration ranging from 50 to 87 months. The data suggest that myxoid solitary fibrous tumors are associated with an indolent clinical course and favorable prognosis.

Myxoid solitary fibrous tumour of the axilla

Solitary fibrous tumors (SFTs) are unusual spindle cell neoplasms initially described in the pleura but have since been discovered in many extrapleural locations. SFT of the kidney is extremely rare, the majority occurring in middle-aged adults. To date, only two pediatric cases of renal SFT have been reported. We report a case of large SFT in the kidney of a 3-year-old boy that was clinically and radiologically thought to be a nephroblastoma. This case is the first pediatric renal SFT to be reported with detailed histopathologic and cytogenetic analyses. SFT should be included in the differential diagnosis of pediatric renal tumors.

Solitary fibrous tumor (SFT) of the central nervous system was first described in 1996. A number of cases have been reported since. The authors present 5 new cases: 4 intracranial and 1 intraspinal. All patients were adults (age range, 47 to 75 years); 4 were male and 1 female; 4 cases were primary tumors; and 1 was a second tumor recurrence. All patients were surgically treated with gross total removal. All cases were histologically examined with immunohistochemical confirmation; 2 tumors exhibited diffuse classic histology, 1 tumor was a cellular variant, 1 tumor was myxoid, and 1 was predominantly classic with focal myxoid features and focally pleomorphic. The postoperative course was uneventful in all. The patient with the cellular variant experienced 2 local recurrences and eventually died of disease 10 years after the initial diagnosis. The patient with the myxoid variant--the tumor studied--which was the second recurrence of a previously misdiagnosed fibrous meningioma surgically treated 15 years earlier, had a recurrence after 2 years for the third time and eventually died of disease. Three patients are alive and well 11.6, 6, and 4 years after surgery. SFT is a rare tumor that needs to be differentiated from some mimickers, mainly fibrous meningioma, hemangiopericytoma, and with regard to the myxoid variant, also adult-onset myxochordoid meningioma and myxoid peripheral nerve sheath tumor. Immunohistochemistry is crucial for the correct diagnosis of SFT. The authors also performed a review of the literature and found a little more than 200 cases on record.

Recurrent orbital solitary fibrous tumor in a 14-year-old girl

Solitary fibrous tumors encompass a heterogeneous group of spindle cell neoplasms, ranging from biologically low-risk lesions to, in rare instances, highly aggressive tumors with malignant potential. Dedifferentiation in solitary fibrous tumors is uncommon and typically occurs in the retroperitoneum, with extrapleural involvement being among the least frequently reported. A 13-year-old male presented with a rapidly enlarging mass in the lower jaw of 20 days duration, involving the submandibular triangle and floor of the mouth. Histopathological examination of the excisional biopsy revealed spindle-shaped cells arranged in compact fascicles with a haphazard distribution, and areas of hyalinization. Immunohistochemical analysis demonstrated positivity for CD34, STAT6, MyoD1, α-SMA, Bcl-2, and CD99, confirming the diagnosis of extrapleural dedifferentiated solitary fibrous tumor (DSFT). The lesion was surgically excised but recurred, likely due to disease progression. Re-excision was planned, but the child died 10 days before surgery.

Conjunctival stromal tumour: case report and review of the literature

Unclassified pediatric renal stromal tumor overlapping with metanephric stromal tumor and solitary fibrous tumor with diffuse S-100 protein expression

Solitary fibrous tumors are mesenchymally derived masses most commonly originating from the lung pleura. Herein, we report a 6-month-old presenting with syndrome of inappropriate antidiuretic hormone secretion (SIADH) and a suprasellar mass. The mass proved to be a solitary fibrous tumor. This case and salient literature are reviewed. To our knowledge, this is the youngest patient to be described with a mass of this type within the central nervous system.

Childhood hypertension is getting more attention in recent years. We present a case report of a rare cause of secondary arterial hypertension in a teenage girl - a solitary fibrous tumor of the kidney. The case demonstrates that standard imaging techniques, computed tomography and magnetic resonance imaging, are not fully reliable in the diagnosis of renovascular hypertension. A 15-year old girl was admitted to the Pediatric Department because of episodes of stiffness in the limbs, accompanied by pale skin and lips, dated 4 months back. During these episodes, high blood pressure up to 160/100 mmHg was measured. A 24-hour blood pressure monitoring demonstrated arterial hypertension stage II. Renovascular hypertension was suspected, but the computed tomography examination of the abdomen showed normal-sized renal arteries. In the left kidney hilum, an intraparenchymal formation was discovered. The data presented a non-specific lesion with a wide differential diagnosis. Given the fact that the patient had been treated with an ACE-inhibitor, serum renin level could not be correctly interpreted. The lesion was removed through a laparoscopic intervention. Intraoperatively, the tumor was compressing a small intra-renal vessel - a finding that hadn`t been discovered by the previous imaging studies. The final pathologist diagnosis was: solitary fibrous tumor. During the next six months of follow-up, the maximal blood pressure values of the patient were up to 120/80 mmHg. Solitary fibrous tumors of the kidneys are infrequent in children. The presented case displays a rare form of initial clinical manifestation of this tumor. It is also a demonstration that standard imaging techniques are not able to get a precise visualization of the small intra-renal vessels. At the same time, the decision of whether or not to perform a more invasive procedure should be based on the clinical conditions and risks of the individual patient.

We present a case of a myxoid and lipomatous solitary fibrous tumor that was observed in a 67-year-old man. The tumor, which had a maximum diameter of 10 cm, was located in the soft tissues of the dorsal region and appeared macroscopically well delimited and encapsulated. Upon cutting, a markedly gelatinous internal surface was observed. A microscopic study revealed an intense and diffusely myxoid neoplasia, with small areas of adipose aspect, in which histological (staghorn vessels, perivascular hyalinization, fusiform cells of benign aspect) and immunohistochemical (intensive positivity for CD34, Bcl-2 and Cd99 and negativity for muscle markers) data were consistent with a solitary fibrous tumor were observed. To conclude, the main characteristics of this lesion are discussed, and a differential diagnosis is established with other entities.

Cytopathology of myxofibrosarcoma: a study of 66 cases and literature review