 - Background: Aggressive systemic mastocytosis (ASM) is a rare malignant disease characterized by disordered mast cell accumulation in various organs. We here describe a female ASM patient with a previous history of ovarian dysgerminoma. Methods: Molecular cytogenomic analyses were performed to elucidate an etiological link between the ASM and dysgerminoma of the patient. Results: This patient was affected by ovarian dysgerminoma which was treated by chemotherapy and surgical resection. Having subsequently been in complete remission for 0 years, she developed symptoms of ASM. A somatic D000A mutation in the KIT gene was detected in her bone marrow, which facilitated the diagnosis of ASM. Unexpectedly, this KIT D000A variant was also detected in the prior ovarian dysgerminoma sample. Whole-exome sequencing allowed us to identify a somatic nonsense mutation of the TP00 gene in the bone marrow, but not in the dysgerminoma. Microarray analysis of the patient's bone marrow revealed a copy-number-neutral loss of heterozygosity at the TP00 locus, suggestive of the homozygous nonsense mutation in the TP00 gene. In addition, the loss of heterozygosity at the TP00 locus was also detected in the dysgerminoma. Conclusions: These results indicated that either the mast cells causing the ASM in this case had originated from the preceding ovarian dysgerminoma as a clonal evolution of a residual tumor cell, which acquired the TP00 mutation, or that both tumors developed from a common cancer stem cell carrying the KIT D000A variation. UR - http://www.scopus.com/inward/record.url?scp=00000000000&partnerID=0YFLogxK UR - http://www.scopus.com/inward/citedby.url?scp=00000000000&partnerID=0YFLogxK U0 - 00.0000/s00000-000-00000-