en Pathology Pathology Original Article Original Article <span style="font-size:14px;"><span style="font-family:Times New Roman;"><span style="line-height:13.5pt"><span style="color:#0033ff;"><b><i>Background</i></b><i>:</i></span> Multiple myeloma is still one of deadliest malignancies known. Although many attempts to prognosticate the disease have been done like the International Staging System (ISS), most of the proposed prognostic tools are based merely on laboratory tests and hence prone to analytical errors in large and high-volume centers. This study aims to evaluate the prognostic effectiveness of histopathologic components of bone marrow and compare it to the results of laboratory-based prognostic tools. </span><br> <span style="line-height:13.5pt"><span style="color:#0033ff;"><b><i>Methods:</i></b></span> This cross-sectional study, bone marrow specimens of 93 multiple myeloma patients underwent aspiration and biopsy evaluated. The primary outcome was overall survival (OS) based on plasma cell percentage. The secondary outcomes were also OS based on angiogenesis using IHC marker CD34, nuclear atypia level, BM involvement pattern and the presence of fibrosis in bone marrow specimens. All biopsy specimens assessed using light microscopy on Hematoxylin and Eosin and IHC staining. Giemsa staining assessed for aspirate specimens.</span><br> <span style="line-height:13.5pt"><span style="color:#0033ff;"><b><i>Results:</i></b> </span>Of 93 patients, 63.4% were dead. Median survival was 34.0 months (95% CI [24.6; 43.3]) and the average age at diagnosis was 65 years (highest 84 and lowest 40). Patients with bone marrow plasma cell count of over 70%, had a hazard ratio (HR) of death of 4.7 times more than those with plasma cell count between 10-25%. Similarly, diffuse infiltration pattern (HR 4.67) and blastic morphology (HR 4.17) associated with a significant worse prognosis (p=0.03).<span dir="RTL" lang="FA"><span style="color:red"></span></span></span><br> <span style="line-height:13.5pt"><span style="color:#0033ff;"><b><i>Conclusion</i></b><i>:</i></span> Comparing to laboratory-based ISS, wider HR of death spectrum in this study proposes a potential more precise, robust and easy-to-use prognostication tool.</span></span></span><br> &nbsp; Multiple Myeloma, histopathological prognosis, International Staging System 562 569 http://caspjim.com/browse.php?a_code=A-10-1149-3&slc_lang=en&sid=1 Niloofar Arefi Sigaroudi nas.arefi@gmail.com 100319475328460053406 100319475328460053406 No Student Research Committee, Babol University of Medical Sciences, Babol, Iran Mohsen Vakili Sadeghi mvakili89@gmail.com 100319475328460053407 100319475328460053407 No Cancer Research Center, Health Research Institute, Babol University of Medical Sciences, Babol, Iran Housein Ghorbani Ghorbani7958@yahoo.com 100319475328460053408 100319475328460053408 No Clinical Research Development Unit of Rouhani Hospital, Babol University of Medical Sci- ences, Babol, Iran Davood Jahansouz djahansouz@gmail.com 100319475328460053409 100319475328460053409 No Cancer Research Center, Health Research Institute, Babol University of Medical Sciences, Babol, Iran Hoda Shirafkan hodashirafkan@gmail.com 100319475328460053410 100319475328460053410 No Social Determinants of Health Research Center, Health Research Institute, Babol University of Medical Sciences, Babol, Iran Mohammad Ranaee drm.ranaee@yahoo.com 100319475328460053411 0009-0002-3155-0008 Yes 3. Department of Pathology, Ayatollah Rouhani Hospital Research Development Unit, Babol University of Medical Sciences, Babol, Iran