Question

a neoplastic disease of bone marrow of unknown etiology that produces an absolute increase in the concentration of erythrocytes. a patient with this condition usually has a dusky red coloration of the skin and thrombosis in small blood vessels due to increased viscosity. polycythemia rubra vera waldenstrom macroglobulinemia multiple myeloma hyperviscosity syndrome

Explanation:

Polycythemia rubra vera is a neoplastic bone - marrow disease. It causes an absolute increase in erythrocyte concentration. Symptoms like dusky red skin (due to increased red blood cells) and thrombosis (from increased blood viscosity) match the description. Waldenstrom macroglobulinemia involves abnormal plasma cells and monoclonal immunoglobulins. Multiple myeloma is characterized by malignant plasma cells and bone lesions. Hyperviscosity syndrome can be a complication of other conditions (like Waldenstrom macroglobulinemia) but is not a primary neoplastic bone - marrow disease with the described erythrocyte - specific increase.

Answer:

Polycythemia rubra vera