INTRODUCTION: Patients who undergo hematopoietic stem cell transplantation to treat hematologic malignancy are at risk of recurrent disease including myeloid sarcoma, an extramedullary collection of leukemic cells. Isolated extramedullary relapse after transplant in the form of a myeloid sarcoma is rare (< 1%). In women, the reproductive tract is often overlooked as a potential site of hematologic malignancy recurrence. METHODS: At our center, we assess women for symptoms of genital chronic graft-versus-host disease and conduct visual inspection of the lower reproductive tract, cervical cytology and human papillomavirus screening as part of post-transplant gynecology care. We present two cases of myeloid sarcoma occurring post-transplant isolated to the female reproductive tract and breast identified during routine gynecologic examination. RESULTS: The first case is a recurrence of mastocytosis manifesting as vaginal bleeding and cervical mass. The second is recurrent acute myeloid leukemia found in a large pelvic and bilateral breast granulocytic sarcoma. CONCLUSION: The sole manifestation of relapse of hematologic malignancy post-transplant may be a myeloid sarcoma in the reproductive tract or breast. Autopsies of women with acute myeloid leukemia show 36% and 40% involvement of the ovary and uterus, respectively — suggesting involvement of the female reproductive tract is more common than clinically suggested. Routine gynecologic care not only detects common post-transplant complications of human papillomavirus disease and genital graft-versus-host disease, but also is important to identify recurrent malignancy, potentially enabling earlier diagnosis and treatment.