Multiple Myeloma Extramedulary Disease Samples FFPE

This retrospective observational study aims to determine the feasibility of assembling a cohort of formalin-fixed paraffin-embedded (FFPE) tissue samples from patients with extramedullary multiple myeloma and linking these materials with associated clinical and pathological data. All samples originate from routine diagnostic procedures performed as part of standard clinical care; no prospective interventions or additional tissue collection are involved. The study evaluates whether archived FFPE specimens and corresponding clinical information can be systematically identified, retrieved, and abstracted using a predefined standardized workflow. Histopathological review and immunohistochemical markers routinely assessed during diagnostic work-up (CD138, CD56, MUM1, light chains) will be used to confirm the diagnosis and describe tumor features. Feasibility will be defined by the proportion of screened cases for which both adequate FFPE material and sufficient clinical data are available to allow inclusion. The purpose of the study is to generate a structured dataset enabling future biomarker research and to assess whether the operational workflow used for case identification, data abstraction, and sample processing can be reliably scaled for larger retrospective cohorts.