Malignant solitary fibrous tumor in the central nervous system treated with surgery, radiotherapy and anlotinib: A case report

Abstract

Background: Solitary fibrous tumor (SFT) of the central nervous system is rare. It is predominantly benign and rarely malignant. There is no established standardized treatment regimen for malignant intracranial SFTs.

Case summary: We present a rare case of SFT in a 9-year-old girl with a space-occupying effect in the frontal-parietal lobes. She underwent craniotomy, and the mass was resected. Immunohistochemistry examination of the specimen showed that Ki-67 proliferation index staining was highly positive in 80% of tumor cells. Whole exome sequencing of the surgical tissue showed 38 somatic gene mutations and 1 gene amplification such as fibroblast growth factor receptor 4 or TP53. At 1.5 mo after surgery, head magnetic resonance imaging revealed that the tumor had recurred. The patient received 60 Gy and 30 fractions of intensity modulated radiotherapy. The patient then received anlotinib 8 mg po qd for 1-14 d of a 21 d cycle. Following this regimen, the patient achieved stable disease for > 17 mo. Magnetic resonance imaging at 1.5 year after surgery showed that the tumor had not progressed.

Conclusion: This is the first reported case of SFT of the central nervous system treated with surgery, radiotherapy and anlotinib. This regimen may be an effective treatment option for malignant intracranial SFT patients.

Keywords: Anlotinib; Biological therapy; Case report; Mutation; Recurrence; Sequence analysis.

Figure 1

Treatment timeline and radiography. A: The treatment timeline; B: A head computed tomography scan revealed a quasi-circular mass in the left frontal-parietal region with high-density and associated hemorrhage. Brain magnetic resonance imaging (MRI) revealed low signals on T1 weighted imaging with high surrounding signals. High signals on T2 weighted imaging with low surrounding signals were observed, with marked enhancement on contrast measuring 4.8 cm × 5.0 cm × 4.5 cm in the left motor area of the frontal-parietal lobes (axial, sagittal and coronal views); C: Gadolinium-enhanced MRI imaging in axial, sagittal and coronal views 1 mo after surgery. MRI imaging showed no residual tumor; 1.5 mo after surgery, MRI imaging showed a solid mass. Five months and 1.5 year after surgery, MRI imaging showed that the tumor had not progressed. MRI + C: Gadolinium-enhanced magnetic resonance imaging.

Figure 2

Hematoxylin and eosin staining and immunohistochemistry examination of the specimen. A: Hematoxylin and eosin staining showed that a large number of spindle or oval cells were diffusely distributed, with deep staining of a null, “staghorn” vascular pattern, hypercellularity and increased mitotic activity were observed in the tumor (> 4 mitosis/10 high-power fields). Hematoxylin and eosin, 100 ×; B: Hematoxylin and eosin staining, 400 ×; C: Positive for CD99, 200 ×; D: Positive for Bcl-2, 200 ×; E: Positive for TP53, 200 ×; F: Positive for IDH1, 200 ×; G: Positive for TLE-1, 200 ×; H: Positive for vimentin, 200 ×; I: High Ki-67 proliferation index: 80%, 200 ×; J: Negative for CD34, 200 ×; K: Negative for STAT6, 200 ×; L: Negative for S100, 200 ×.

Figure 3

Circos 2D track plot of somatic variant across chromosomes in solitary fibrous tumor. In the inner ring, black denotes missense mutation, blue denotes frameshift mutation, and red denotes gene amplification.