Auer rod-like inclusions in marginal zone lymphoma: a potential diagnostic pitfall

Area of Science:

• Hematology
• Oncology
• Pathology

Background:

• Peripheral blood smear examination is crucial for diagnosing hematologic malignancies.
• Auer rods are characteristic cytoplasmic inclusions found in myeloid blasts, strongly suggesting acute promyelocytic leukemia.
• Diagnostic challenges arise when atypical morphologic features mimic other hematologic conditions.

Purpose of the Study:

• To report a rare case of marginal zone lymphoma presenting with morphologic features mimicking acute promyelocytic leukemia.
• To emphasize the importance of comprehensive diagnostic workup beyond initial morphologic findings.
• To highlight that Auer rod-like inclusions are not exclusive to myeloid neoplasms.

Main Methods:

• Peripheral blood smear examination for morphologic assessment.
• Flow cytometry for immunophenotypic analysis of lymphoid and myeloid populations.
• Bone marrow biopsy for histopathological evaluation and definitive diagnosis.

Main Results:

• Peripheral blood smear revealed atypical lymphoid cells with Auer rod-like cytoplasmic inclusions.
• Flow cytometry identified a mature monoclonal B cell population without myeloid differentiation.
• Bone marrow biopsy confirmed the diagnosis of marginal zone lymphoma.

Conclusions:

• Marginal zone lymphoma can present with atypical cytoplasmic inclusions resembling Auer rods.
• Relying solely on morphologic features can lead to diagnostic errors.
• Integrated diagnostic approaches including flow cytometry and bone marrow biopsy are essential for accurate hematologic diagnoses.