[Primary isolated myeolosarcoma in childhood].

Area of Science:

• Pediatric Oncology
• Hematology
• Cancer Research

Background:

• Extramedullary myelosarcomas are uncommon initial presentations of acute myeloid leukemia (AML).
• These rare manifestations can precede bone marrow involvement by weeks to months.
• Early diagnosis and treatment are crucial for patient outcomes.

Purpose of the Study:

• To investigate the incidence and characteristics of isolated extramedullary myelosarcomas in children.
• To evaluate the diagnostic challenges and treatment outcomes for these rare AML presentations.
• To emphasize the importance of considering extramedullary myelosarcomas as an initial sign of AML.

Main Methods:

• Retrospective analysis of pediatric patients diagnosed with extramedullary myelosarcomas during AML-BFM 87 and 93 studies.
• Review of clinical data, tumor infiltration sites, FAB classification, relapse rates, and survival data.
• Comparison of outcomes with the general AML-BFM 87/93 cohort.

Main Results:

• Extramedullary myelosarcomas were diagnosed in 2.6% (17/654) of pediatric patients.
• Predominant tumor cell types were myelomonocytic (M4) or monoblastic (M5).
• Common infiltration sites included skin (8 cases), mucosa (2), CNS (2), and orbita (2).
• High relapse rate (79%) and poor survival (0.27 +/- 0.13) were observed.
• Diagnostic delays and inadequate initial treatment contributed to poor outcomes.

Conclusions:

• Isolated extramedullary myelosarcomas represent a rare but significant initial manifestation of AML in children.
• Suspicious skin lesions or tumors warrant consideration for primary AML.
• Intensive, AML-specific chemotherapy is recommended for improved outcomes.