Intraosseous Schwannoma of the Proximal Humarus With Pathologic Fracture

Abstract Purpose Intraosseous schwannomas are extremely rare in the humerus, and less than 5 cases have been reported previously in the literature. This is the first report of its origin in the proximal humerus with pathologic fracture. we herein present this case for discussing the reason for its rarity and sharing our experience of management.Case presentation A 55-year-old female patient who presented with pain in the right shoulder, which caused by tripping and falling over a board. Radiographs, computed tomography (CT) and magnetic resonance imaging (MRI) showed considerable tumor in proximal humerus, which connected with a fracture. For this suspected tumor, we performed two operations. Pathological examination demonstrated typical picture of a schwannoma, showing whorls and interlacing fascicles of schwannoma spindle cells. Immunohistochemistry, The tumor cells were diffusely positive for S-100 protein, SOX-10 and CD68, while they were completely negative for desmin, DOG-1, AE1/AE3 and P63. The ki-67 index was about 10%. No mitoses or features of malignancy were identified. Finally, a diagnosis of benign schwannoma with focal of actively proliferated cells was made.Methods The treatment for intraosseous neurilemmomais with pathologic fracture include excisional biopsy, curettage, bone allograft, and fracture fixation. Results The patient recovered well. After the surgery, the patient gradually regained mobility and pain subsided. There was no recurrence after 6 months follow-up by X-ray.Conclusion In our case, the tumor with higher CD68 staining were likely to demonstrate that the tumor volume increase is not only based on cell proliferation, but also intratumoral hemorrhage, vascularization, and inflammation, which may be produce rarefaction of the bone and lead to bone fracture after a trivial trauma.