case_images: PMC11116620_01
case_images: Three-Tesla MRI. (A) Coronal twist MR-A, (B) T2-weighted, (C, D) and T1 weighted MRI with gadolinium enhancement demonstrates an arteriovenous fistula originating of the left vertebral artery with early filling of intra- and extraspinal venous vascular convolutes (circle).
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case_images: She reveals multiple cafe-au-lait spots on her skin and numerous subcutaneous masses on her whole body as the classical NF stigmata; because of new, immobilizing neck pain and intractable cervicobrachial pain in her left arm, magnet resonance imaging (MRI) of the cervical spine was performed ( Figure 1 ), which revealed a long-distance contrast-enhancing mass along the cervical spine. Figure 1 ) and computer tomography angiography (CT-A) were performed for further diagnostic workup, with results suggesting the cervical mass to be an arteriovenous fistula. Finally, spinal digital subtraction angiography revealed an intra-, extraspinal, retro- and parapharyngeal arteriovenous fistula with an extension from the foramen magnum to C4, with the primary feeder being the vertebral artery on the left side and small feeders of the cervical ascendence artery and the deep cervical artery ( Figure 3 ).
case_images: Imaging. 18F-FDG-PET/CT (A, B) demonstrates FDG accumulation in the right sciatic nerve (arrow) with an SUVmean/max of 6.8/11.7. Coronar (C) and axial (D) view of T1-weighted gadolinium-enhanced MRI shows a homogenous gadolinium-enhanced 5.2x2.4x2.8 cm large mass arising from the dorsal parts of the sciatic nerve (arrow) in the distal third of the thigh:additional multiple small neurofibromas throughout the sciatic nerve (*), intramuscular and subcutaneous are visualized.
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case_images: Consequently, an FDG-PET/CT was performed to acquire a whole-body staging and evaluate a possible biopsy target ( Figure 2 ).
case_images: Endovascular treatment. Digital subtraction angiography demonstrates the vertebral arteriovenous fistula (A) before (circle) and (B) after treatment (arrow).
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case_images: Figure 1 ) and computer tomography angiography (CT-A) were performed for further diagnostic workup, with results suggesting the cervical mass to be an arteriovenous fistula. Finally, spinal digital subtraction angiography revealed an intra-, extraspinal, retro- and parapharyngeal arteriovenous fistula with an extension from the foramen magnum to C4, with the primary feeder being the vertebral artery on the left side and small feeders of the cervical ascendence artery and the deep cervical artery ( Figure 3 ).
case_images: Intraoperative images. Macroscopic appearance of the tumor (asterisk) originating from the sciatic nerve (arrow) in situ and after resection.
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case_images: Microsurgical gross total resection was performed using intraoperative ultrasound and nerve stimulation ( Figure 4 ).
case_images: Histopathological analysis and copy number variation (CNV) profile. (A-I) Histopathological analysis: H&E stained sections (A-C) showing typical histopathological findings of neurofibroma, including cytologically bland, wavy nuclei, loose matrix architecture with collagen bundles, so-called "shredded carrots" in some regions (A); hypercellularity in other regions (B) and nuclear atypia (C). Necrosis and increased mitotic activity were absent. Immunohistochemistry (D-I) shows that a subset of tumor cells expressed S100 (D) and CD34 (E), respectively. A small subset of tumor cells in focal small clusters expressed GLUT1. Entrapped neurofilament (NF) positive axon bundles within the tumor (G). P16, one protein product of the CDKN2A gene, highlights a subset of tumor cells; focal complete loss of p16 was seen (H). Ki-67 proliferation fraction was around 5%. (J) The CNV profile of the tumor was generated based on DNA methylation analysis by microarray for 850,000 CpG sites (Infinium MethylationEPIC/ 850k analysis). No chromosomal losses or gains were observed. The CNV profile, however, suggested deletion of CDKN2A/B (light blue dot) on chromosome 9.
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case_images: Neuropathology at the University Hospital Aachen, which is particularly specialized in peripheral nerve tumors. Both departments came to the same conclusion: histopathological diagnosis showed a tumor with typical morphological and immunohistological features of neurofibroma in many regions but focally increased cellularity and nuclear atypia. Necrosis and increased mitotic activity, both of which would suggest malignancy, were not seen ( Figure 5 ). DNA methylation analysis by microarray (Infinium MethylationEPIC/850k analysis) assigned this tumor to the methylation class "schwannoma" matching score >0.99 (v12.8) and suggested CDKN2A/B deletion ( Figure 5 ).