An incidental B-lymphoblastic leukemia/lymphoma in a prophylactic salpingo-oophorectomy from a patient with germline BRCA1 mutation

B-lymphoblastic leukemia/lymphoma (B-ALL) is a malignant neoplasm of immature B lymphocytes. Occasionally, B-ALL may exhibit morphological and immunophenotypic overlaps with other hematologic malignancies such as B-ALL with isolated myeloperoxidase (MPO) expression which may complicate diagnosis. <i>BRCA1</i> and <i>BRCA2</i> are tumor suppressor genes involved in homologous recombination and DNA repair. While germline mutations in these genes are well-established risk factors for breast and ovarian cancers, the association between <i>BRCA1/2</i> mutations and hematologic malignancies remains underexplored. We present a rare case of B-ALL with isolated MPO expression, discovered incidentally in prophylactically resected ovaries of a patient with a germline <i>BRCA1</i> mutation, and review the literature exploring this potential association.