Unresponsive Systemic Mastocytosis in a Young AML With RUNX1::RUNX1T1 Fusion With Rare KIT c.1255_1257delGAC...

Area of Science:

• Hematology
• Oncology
• Molecular Diagnostics

Background:

• Systemic mastocytosis with associated acute myeloid leukemia (SM-AML) is a rare hematologic malignancy.
• KIT mutations, particularly p.D816V, are commonly associated with SM-AML.
• Atypical presentations necessitate thorough diagnostic approaches.

Purpose of the Study:

• To report the first case of SM-AML with a rare KIT exon 8 deletion (p.Asp419del).
• To emphasize the importance of integrated diagnostic methods for rare mutations.
• To discuss therapeutic implications in complex cases.

Main Methods:

• Case report of a 17-year-old female with RUNX1::RUNX1T1-positive AML and mast cell proliferation.
• Utilized morphology, immunophenotyping, and polymerase chain reaction for diagnosis.
• Routine next-generation sequencing (NGS) failed to detect the specific KIT mutation.

Main Results:

• Identified a rare KIT exon 8 deletion (p.Asp419del) in the patient.
• Achieved initial remission with chemotherapy and imatinib.
• Patient experienced persistent mastocytosis and ultimately succumbed to septic shock.

Conclusions:

• This case represents the first documented instance of SM-AML with KIT p.Asp419del.
• Highlights limitations of routine NGS in detecting certain rare mutations.
• Underscores the need for comprehensive molecular testing and individualized treatment strategies for atypical SM-AML.