Rapidly fatal leukemia comprising pleomorphic large granular lymphocytes: a report of 2 cases

Area of Science:

• Hematology
• Immunology
• Oncology

Background:

• Large granular lymphocytes (LGLs) are cytotoxic T or NK cells with distinct morphology.
• Neoplastic T-LGLLs are morphologically similar to normal LGLs, while ANKL shows greater variation.
• Distinguishing between T-LGLL and ANKL can be challenging due to overlapping features.

Observation:

• Two leukemia cases with pleomorphic LGLs were analyzed.
• Case 1: Patient presented with altered consciousness and unstable hemodynamics, showing CD2+, CD56+, HLA-DR+ LGLs lacking CD3 expression, consistent with ANKL.
• Case 2: Patient presented with sudden death, exhibiting LGLs with variable nuclear shapes and a CD2+, cCD3+, CD3-, CD56+ phenotype with T cell receptor gene rearrangement, indicative of T-LGLL.

Findings:

• Immunophenotyping and genetic analysis are crucial for differentiating LGL leukemia subtypes.
• ANKL and T-LGLL can present with pleomorphic LGL morphology, complicating initial diagnosis.
• Both presented cases were rapidly fatal, underscoring the aggressive nature of these rare leukemias.

Implications:

• Accurate diagnosis of rare LGL leukemias necessitates a combination of morphological, immunophenotypic, and molecular analyses.
• A multidisciplinary team approach is vital for managing these challenging hematologic malignancies.
• Early and precise diagnosis may improve patient outcomes, although these cases were rapidly fatal.