Diagnostic concordance between bone marrow aspirate and trephine biopsy in hematological neoplasms and non-hematological marrow infiltrations.

Evaluating concurrent bone marrow aspirate (BMA) and trephine biopsy (BMB) specimens demonstrates significant diagnostic complementarity, reducing false-negative rates in plasma cell dyscrasias and marrow infiltrations, and proving that combined evaluation remains essential for accurate laboratory staging across diverse hematological malignancies. This retrospective study at the South Egypt Institute for Oncology evaluated 430 patients who underwent simultaneous BMA and BMB between December 2023 and December 2025 for suspected or confirmed malignancies. Inadequate samples, including hemodiluted or dry tap aspirates and core lengths under 1.5 cm, were excluded from the analysis. Two blinded hematopathologists independently reviewed the slides, and concordance, diagnostic performance metrics, and Cohen's kappa (k) were calculated across distinct disease categories. The cohort, with ages ranging from 4 months to 81 years and a male-to-female ratio of 1.4:1, comprised lymphoproliferative neoplasms (LPN; 35.6%), marrow infiltration (24.7%), plasma cell dyscrasias (19.8%), myeloid neoplasms within the MDS/MPN spectrum (11.2%), and acute leukemias (8.8%). Diagnostic concordance varied significantly by category, where plasma cell dyscrasias demonstrated the lowest concordance at 22.4% (19/85), followed by LPN at 40.5% (62/153), and marrow infiltrations at 41.5% (44/106). Conversely, the MDS/MPN spectrum achieved 68.8% (33/48) concordance, while acute leukemia demonstrated the highest agreement at 84.2% (32/38). Consequently, the diagnostic utility of BMA is highly disease-dependent. While BMA reliably detects diffuse, cytologically homogeneous conditions like acute leukemia, BMB remains mandatory for capturing focal, patchy, or architecture-dependent lesions, such as plasma cell dyscrasias and metastatic infiltrations. Both modalities must be used complementarily to ensure comprehensive diagnostic accuracy.