Pediatric central nervous system solitary fibrous tumor: case report

Solitary fibrous tumor of the orbit in a 1-year-old patient: a case report

Solitary fibrous tumors (SFTs) are rare neoplasms of mesenchymal origin. While the mean age of presentation is 58 years old, we report the case of the youngest documented patient with an SFT of the orbit. A 13-month-old child was evaluated for eyelid asymmetry and then referred to the oculoplastic service. On examination, a soft tissue mass of the right inferomedial orbit was observed. MRI demonstrated a well-circumscribed, extraocular lesion in the inferomedial right orbit, potentially fibrous in nature. Excision was performed without complications. Pathologic examination demonstrated fibrous tissue proliferation with a staghorn vascular pattern, as well as benign fibrous cells with tapering nuclei and abundant pericellular reticulin. Immunohistochemistry (IHC) demonstrated that the cells stain diffusely positive for CD34 and vimentin. With the MRI findings, pathology, and IHC, the diagnosis was confirmed to be SFT. SFTs of the orbit, although rare, may occur in the pediatric population.

Syndrome of inappropriate secretion of antidiuretic hormone as an initial sign of primary central nervous system lymphomas in the hypothalamus

BACKGROUND

Primary central nervous system lymphoma (PCNSL) rarely originates in the hypothalamus. Hypothalamic PCNSL can present with various symptoms specific to dysfunction of the hypothalamus, including consciousness disturbance, cognitive impairment, hypopituitarism, and diabetes insipidus (DI). However, it remains unclear whether syndrome of inappropriate secretion of antidiuretic hormone (SIADH) can present as an initial sign of hypothalamic PCNSL.

METHODS

Ninety-nine patients with PCNSL were diagnosed between January 2006 and December 2020 at our institutes. The initial symptoms and signs, hypothalamic-pituitary functions, serum sodium (Na) value, Karnofsky Performance Status (KPS) score on admission, and duration from onset to diagnosis were retrospectively investigated from the medical charts.

RESULTS

Eight and 91 patients had hypothalamic PCNSL (hypothalamic group) and PCNSL located in other regions (control group), respectively. Patients' pathological diagnoses were diffuse large B-cell lymphoma (97 patients) and intravascular lymphoma (two patients). Six patients presented with hyponatremia derived from SIADH or suspected SIADH, and one presented with DI. Statistically significant differences between the hypothalamic and control groups were detected only in the preoperative serum Na values and KPS scores.

CONCLUSION

SIADH can be an initial presentation of hypothalamic PCNSL. Early detection of hypothalamic PCNSL from SIADH may lead to proper management and improved prognosis.

Solitary Fibrous Tumor of the Orbit: A Case Series With Clinicopathologic Correlation and Evaluation of STAT6 as a Diagnostic Marker

PURPOSE

To retrospectively describe the clinical characteristics, management, and outcomes of a series of patients with solitary fibrous tumor (SFT) of the orbit and to evaluate signal transducer and activator of transcription 6 (STAT6) as a diagnostic marker.

METHODS

Review of a retrospective, noncomparative, consecutive series of patients treated at a single institution with a histopathologic diagnosis of SFT. Demographic, clinical, and imaging data were collected, and paraffin-embedded tissue sections were stained to evaluate for the presence of STAT6 and other pertinent markers.

RESULTS

Twenty-one patients were identified. Most presented with painless progressive proptosis or eyelid swelling for less than 6 months. Imaging revealed well-circumscribed, firm, variably vascular contrast-enhancing lesions with low to medium reflectivity on ultrasound. Four tumors were histopathologically malignant. All tumors were primarily excised, and 1 patient required exenteration. Two patients were treated with adjuvant radiation therapy. Six patients had recurrent disease of which 3 underwent repeat excision, and 2 were observed. No metastatic disease or attributable deaths were observed. All lesions with available tissue stained positively for both CD34 and STAT6.

CONCLUSION

This is the largest single institution case series of orbital SFT with clinicopathologic correlation and the largest series to confirm the presence of STAT6 in orbital lesions. The management of SFT remains challenging due to unpredictable tumor behavior, and complete excision is the generally recommended treatment. It remains unclear whether a subset of asymptomatic patients with histopathologically benign disease can be durably observed without negative sequelae.

Intracranial Solitary Fibrous Tumor of the Skull Base: 2 Cases and Systematic Review of the Literature

BACKGROUND

Intracranial solitary fibrous tumors (ISFTs) are rare neoplasms of mesenchymal origin that originate from the meninges. ISFTs of the skull base can be challenging to treat, as resection can be complicated by skull base anatomy. We present 2 cases of ISFT, the first manifesting with compressive cranial neuropathy from Meckel cave involvement and the second a posterior fossa lesion causing symptomatic hydrocephalus.

METHODS

A systematic review was performed according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The PubMed database was queried with title/abstract keywords "intracranial," "solitary fibrous tumor," "hemangiopericytoma," "SFT," and "HPC." Search results were reviewed to exclude cases not involving the skull base. References from all selected articles were reviewed for potential additional cases. Patient demographic and clinical data from 58 identified skull base cases were collected for qualitative synthesis.

RESULTS

Visual disturbances were the most common presenting symptom (30 cases, 52%) followed by headache (22 cases, 38%). The most common site of involvement was the sellar/parasellar region (18 cases, 31%) followed by middle fossa/temporal bone (14 cases, 24%). Resection was performed in 55 cases; gross total resection was reported in 26 cases (45%) and subtotal resection was reported in 21 cases (36%). Tumor recurrence was documented in 15 cases (26%) with median and mean follow-up periods of 16 and 29.9 months, respectively.

CONCLUSIONS

We discuss presentation, imaging, histopathology, and management considerations for ISFTs while highlighting the potentially complex nature of skull base lesions and need for multidisciplinary approach to treatment.

Solitary Fibrous Tumors in Pediatric Patients: A Rare and Potentially Overdiagnosed Neoplasm, Confirmed by STAT6 Immunohistochemistry

Pathological diagnosis of solitary fibrous tumor (SFT) in the pediatric population is challenging, as it occurs uncommonly in this age-group and resembles other spindle cell neoplasms. SFT contains a NAB2-STAT6 fusion gene, which can be reliably detected using STAT6 immunohistochemistry. Positive staining is highly sensitive and specific. We sought to investigate the utility of STAT6 immunohistochemistry, to show how commonly SFT was historically recognized at 3 academic pediatric institutions, to reclassify them when appropriate, and to demonstrate features of major mimics of SFT. Our series included cases with a previous diagnosis of SFT or for which SFT was among key considerations, from 3 major academic pediatric hospitals seen over the past 30 years. Of 18 tumors identified, only 3 tumors from 2 patients demonstrated positive STAT6 staining as well as the typical histology and immunophenotype seen in SFT. The remaining 15 tumors were reclassified based on morphology, additional immunohistochemistry and fluorescence in situ hybridization as desmoid-type fibromatosis (3 tumors), nerve sheath/neural tumors (3 tumors), low-grade fibromyxoid sarcoma, medallion-like dermal fibroma, poorly differentiated Sertoli cell tumor, nodular/proliferative fasciitis, calcifying fibrous tumor, aneurysmal bone cyst of soft tissue, STAT6-negative SFT with adipocytic differentiation, undifferentiated small round blue cell tumor, and scar (1 tumor each). Our study confirms that SFT is rare in the pediatric population and that it is potentially overdiagnosed. STAT6 immunohistochemistry is recommended to confirm the diagnosis of SFT in the pediatric population.

Solitary fibrous tumors of the spine: a pediatric case report with a comprehensive review of the literature

Solitary fibrous tumors of the spine are rare lesions. Their description in the literature is limited to case reports and small case series. While generally benign lesions, they can recur and occasionally occur as malignancies. Here the authors present the case of a 10-year-old boy, the youngest patient and first preadolescent reported thus far, with this condition. In addition, they perform a comprehensive review of all previously published cases of spinal solitary fibrous tumors.