Introduction/Background Myeloid Sarcoma (MS) is an uncommon condition characterised by proliferation of immature myeloid cells in extra-medullary sites. The most common are lymph nodes, central nervous system, bones, and soft tissues. MS of the gynaecological tract is rare, especially in the uterine cervix. Patients with acute myeloid leukaemia (AML) are prone to have MS at any moment of the disease, especially after bone marrow transplantation (BMT).

Methodology Molecular biology, immunohistochemical and immunophenotypic analysis of an unusual case of MS in the cervix without evidence of bone marrow recurrence, two years after an allogeneic BMT.

Results A nulliparous 32-year-old patient, attending the haematological service due to AML since 2018 at a quaternary Brazilian Naval Hospital, complained of neuropathic and acute abdominal pain. Clinical examination revealed several soft tissue tumorations resembling MS and an abdomen/pelvic magnetic resonance imaging (MRI) peculiarly demonstrated a large uterine mass with compression of the right ureter and pyelocalyceal dilation. Gynaecological clinical exam exhibited a large violaceus mass about 4 cm with anterior and right vaginal wall infiltration. The hypothesis was primary cervical cancer stage IV. The biopsy revealed a massive infiltration of immature myeloid cells with the expression of anti-ERG and myeloperoxidase antibodies. The immunophenotypic analysis of the bone marrow aspirates showed the patient still had a complete remission with minimum residual disease (MRD) negative and a variable number of tandem repeats (VNTR) with full donor chimerism. The patient started chemotherapy with a hypomethylating agent and BCL-2 inhibitor Venetoclax.

Conclusion Decision making on the treatment of cervical MS is challenging due to the absence of gynaecological classification guidelines. In patients in this age group with no offspring, the choice of therapy should consider the fertility issue. Finally, MS should be a differential diagnosis in a patient with a uterine mass and a previous medical history of AML.