Abstract
Abstract Introduction Acquisition of somatic mutations is essential for the development of malignant tumors such as diffuse gliomas. Recent single-cell analyses have pointed out the importance of somatic mosaicism in the pathogenesis of cancer. Here we report a case of IDH (isocitrate dehydrogenase)-mutant astrocytoma that has relapsed after intensive chemoradiation with somatic mosaicism for the IDH1 R132H mutation. Clinical and Pathological Findings A 36-year-old male presented with epileptic symptoms and a mass lesion in the right frontal lobe. A needle biopsy demonstrated IDH-mutant astrocytoma (grade 2). At the age of 41, relapsed tumor was completely resected, and the tumor cells were diffusely positive for IDH1 R132H with grade 4 morphology. Chemoradiotherapy (PAV + IMRT 60Gy/30fr) was added, but contrast-enhanced lesions reappeared 5 months after the initial surgery. The re-excised specimen was grade 4 astrocytoma, and the number of IDH1 R132H-positive tumor cells was very small compared to the total number of tumor cells, suggesting somatic mosaicism for IDH mutations. Conclusion It is imperative to clarify the induction mechanism and significance of somatic cell mosaicism in cancer, and molecular genetic assessment with sequencing and digital PCR would be necessary in addition to immunostaining for accurate molecular diagnoses of the brain tumors.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
