Natural killer cell precursor acute lymphoma/leukemia presenting in an infant

Area of Science:

• Hematology
• Pediatric Oncology
• Immunophenotyping

Background:

• Immature natural killer (NK) cell lymphomas/leukemias are aggressive neoplasms typically affecting adults.
• These malignancies often present with blastic features, extranodal involvement, and lack Epstein-Barr virus association.

Observation:

• A rare case of NK precursor acute lymphoma is presented in an infant.
• The infant exhibited multiple masses, lacked circulating blasts, and had no marrow replacement.
• Diagnostic challenges included the patient's young age, atypical presentation, and blastic morphology mimicking small round blue cell tumors.

Findings:

• The neoplasm displayed a complex immunophenotype: CD56+, CD34+, CD33+, MPO-, cytoplasmic CD3+, CD45-, CD7-, HLA-DR-, and TdT-.
• This immunophenotype overlaps with previously described myeloid/NK precursor acute leukemias and blastic NK cell lymphoma/leukemia.
• The absence of typical lineage-specific markers added to the diagnostic complexity.

Implications:

• This case underscores the importance of a high index of suspicion for diagnosing rare infant NK precursor acute lymphoma.
• Accurate differentiation from solid tumors and other infant hematolymphoid neoplasms is critical for appropriate management.
• Recognizing this entity aids in advancing the understanding and treatment strategies for pediatric lymphoid malignancies.