Published online Sep 6, 2023. doi: 10.12998/wjcc.v11.i25.6000
Peer-review started: June 26, 2023
First decision: July 4, 2023
Revised: July 7, 2023
Accepted: August 8, 2023
Article in press: August 8, 2023
Published online: September 6, 2023
Processing time: 67 Days and 8.4 Hours
The mixed lineage leukemia (MLL)-eleven-nineteen lysine-rich leukemia (ELL) fusion gene is a rare occurrence among the various MLL fusion genes. We present the first case in which myeloid sarcoma (MS) was the only manifestation of adult MLL-ELL-positive acute myeloid leukemia (AML).
We report a case of a 33-year-old male patient who was admitted in June 2022 with a right occipital area mass measuring approximately 7 cm × 8 cm. Blood work was normal. The patient underwent right occipital giant subscalp mass excision and incisional flap grafting. Immunohistochemistry was positive for myeloperoxidase, CD43 and CD45 and negative for CD3, CD20, CD34, and CD56. The bone marrow aspirate showed hypercellularity with 20% myeloblasts. Flow cytometry showed that myeloblasts accounted for 27.21% of the nucleated cells, which expressed CD33, CD38, and CD117. The karyotype was 46, XY, t (11, 19) (q23; p13.1), -12, + mar/46, XY. Next-generation sequencing showed a fusion of MLL exon 7 to exon 2 of ELL. A diagnosis of MLL-ELL-positive AML (M2 subtype) with subcutaneous MS was made.
MLL-ELL-positive AML with MS is a rare clinical entity. Additional research is needed to elucidate the molecular mechanisms of the pathogenesis of MS.
Core Tip: This study described myeloid sarcoma as the first and only manifestation in an adult patient with mixed lineage leukemia-eleven-nineteen lysine-rich leukemia-positive acute myeloid leukemia. Based on our findings and information from a few previous reports, we speculate that our patient had (1): Transformation of preleukemia cells in the marrow followed by spread to extramedullary sites; or (2) homing of preleukemia cells to extramedullary sites, followed by spreading back to bone marrow. The current study helps increase the awareness of this particular disease and reduce the clinical underdiagnosis rate.