[Multiple myeloma from the pathologist's perspective].

Area of Science:

• Hematology
• Oncology
• Pathology

Background:

• Multiple myeloma (MM) is a prevalent hematological neoplasm, constituting about 1% of human cancers.
• Understanding MM diagnostics and classification is crucial for patient management.

Purpose of the Study:

• To describe current diagnostics and classification of MM and related plasma cell neoplasms.
• To provide a pathology-focused overview of MM.

Main Methods:

• Summarized current knowledge on MM pathology and genetics.
• Described tissue-based diagnostics per international consensus and S3 guideline.

Main Results:

• MM involves malignant plasma cells producing monoclonal immunoglobulin, a key disease activity marker.
• MM progresses through stages, from monoclonal gammopathy of undetermined significance (MGUS) to smoldering myeloma, and systemic MM requires differentiation from localized forms.
• MM exhibits significant genetic heterogeneity, categorized into IGH translocation and hyperdiploidy groups, with intratumoral heterogeneity correlating with lesion size.

Conclusions:

• Diagnosis of plasma cell neoplasms requires interdisciplinary evaluation of clinical, serological, pathological, and radiological features per International Myeloma Working Group (IWMG) criteria.
• Molecular markers, particularly cytogenetic aberrations, hold significant prognostic value alongside clinical parameters.