The relationship between prognosis and plasma cell percentage, infiltration pattern, fibrosis and microvessel density in bone marrow biopsies of plasma cell myeloma patients

Plasma cell myeloma (PCM) is a bone marrow based, multifocal neoplastic proliferation of plasma cells. PCM is a monoclonal disease characterized by the presence of anemia, monoclonal protein in the serum and/or urine, osteolytic lesions in the bones, hypercalcemia and renal failure; and the risk of disease increases with age, especially after the age 50. PCM accounts for about 1% of malignant tumours, 10-15% of hematopoetic neoplasms, and 20% of deaths from hematological malignancies. Bone marrow is the site of origin of nearly all PCMs and the proportion of monoclonal plasma cells is often above 10%. But since for a few number of patients this percentage might be lower, specifying a lower limit is not always a valid rule. Biopsy findings are helpful not only for diagnosing but also for determining the prognosis of the patient. In this study, bone marrow biopsies of 135 PCM cases diagnosed between 2015-2017 at Dokuz Eylül University Medical Pathology Department were reevaluated in terms of plasma cell percentage and involvement pattern. Fibrosis was assessed in 132 cases with reticulin staining and microvessel density (MVD) in 51 cases with CD34 staining. The relation of these morphological parameters with stage and survival status was examined. Plasma cell percentage, involvement pattern and MVD showed statistically significant correlation with stage (p<0.001, p=0.001, p=0.011), while bone marrow fibrosis was not correlated (p>0.05). It was found that as the percentage of plasma cells increased (p<0.001), as the involvement pattern changed from interstitial to diffuse (p<0.001) and as the degree of fibrosis increased (p=0.036); MVD increased. There was no significant relationship between survival status and sex, age, stage, percentage of plasma cells, bone marrow involvement pattern, bone marow fibrosis and MVD. The results suggest that evaluation of plasma cell percentage, infiltration pattern, fibrosis and MVD in bone marrow biopsies of newly diagnosed PCM cases may give an idea about disease progression and may be useful in the selection and follow-up of treatment. Key words: plasma cell myeloma, angiogenesis, fibrosis