T-cell lymphoma of the breast and ovary presenting as a second malignant neoplasm in a pediatric leukemia survivor: A case report and literature review

Second malignant neoplasms (SMNs) are rare but serious late effects in childhood acute lymphoblastic leukemia (ALL) survivors. Mature peripheral T-cell lymphomas involving both the breast and ovary are exceedingly rare, and their relationship with germline predisposition variants remains poorly understood. We report a 17-year-old female, previously treated for high-risk B-cell ALL and in sustained remission, who developed bilateral breast and ovarian masses in 2024. Histopathology and immunohistochemistry confirmed a mature T-cell lymphoma (CD7 + , CD99 + , weak CD5/CD3, Ki-67 >90%, TdT – ). Whole-exome sequencing revealed a germline pathogenic BRCA2 variant (c.1910-2A>T) along with additional likely pathogenic variants ( CUX1 , MED12L , POLR3B , PIK3CA ). The disease progressed rapidly despite CHOP chemotherapy, and the patient died shortly after diagnosis. This report describes an exceptionally rare SMN of peripheral T-cell lymphoma with breast and ovarian involvement in a pediatric leukemia survivor. The coexistence of a germline BRCA2 mutation and additional genomic alterations suggests a multigenic predisposition hypothesis. Early incorporation of next-generation sequencing may uncover molecular vulnerabilities and inform alternative therapeutic strategies in refractory hematologic malignancies.