Solitary plasmacytoma of spine with amyloidosis

<p><strong>Objective</strong> To report the diagnosis and treatment of one case of solitary plasmacytoma of spine with amyloidosis and investigate the clinicopathological features combined with literatures. <strong>Methods and Results</strong> The patient was a 46-year-old woman. She suffered from weakness of both lower limbs, unsteady gait and numbness of toes for 20 d. MRI examination revealed an irregular mass behind the spinal cord at T_5-7 level and T_6-7 vertebral body accessory. The enhanced MRI showed obvious heterogeneous enhancement. The border was clear and spinal dura mater was compressed to shift forward. During operation, T_5-7 processus spinosus and vertebral laminae were eroded, and the cortex of bone showed "moth-eaten" erosion. The intraspinal and extradural lesion had rich blood supply, loose bone structure and intact spinal dura mater. Histologically, tumor cells were composed of intensive small cells, and focal plasmacytoid cells were seen. Flake pink staining substance was among them. Artificial cracks were common and multinuclear giant tumor cells were scatteredly distributed. Immunohistochemical analysis showed the cytoplasm of tumor cells were diffusely positive for CD138, CD38 and vimentin (Vim),scatteredly positive for leukocyte common antigen (LCA), and negative for immune globulin κ light chain(IgGκ) and λ light chain (IgGλ), CD99, S-100 protein (S-100), pan cytokeratin (PCK), epithelial membrane antigen (EMA), HMB45 and CD34. The Ki-67 labeling index was 1.25%. Congo red staining showed the pink staining substance was brownish red. Hybridization in situ examination showed the DNA content of IgGκ was more than that of IgGλ. The final pathological diagnosis was solitary plasmacytoma of spine with amyloidosis. The patient was treated with postoperative chemotherapy, and there was no recurrence or metastasis during 18-month follow-up period. <strong>Conclusions</strong> Solitary plasmacytoma of spine with amyloidosis is a rare tumor. The imaging features can offer a few diagnostic cues. However, a clear diagnosis depends on specific histomorphology, immunophenotyping, special staining and hybridization in situ examination.</p><p> </p><p><strong>DOI: </strong>10.3969/j.issn.1672-6731.2017.01.010