PMC3463837_01
(a) T1-weighted contrast sagittal image showing the tumor with irregular margin and intense enhancement on contrast. Bodies of T8 and T9 vertebrae show infiltration. (b) T1-weighted contrast axial image showing the enhancing tumor surrounding and compressing the tumor from all side like a cylinder. (c) Coronal image showing the infiltrative nature of the tumor
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F1
On MRI, there was a grossly infiltrating lesion at the level of T8, T9 and partially extending to T10 level [Figure 1a and c]. T9 vertebral bodies. The lesion was extradural compressing the cord all around like a cylinder which was well seen in the axial cut [Figure 1b]. The lesion had an irregular margin with intense homogenous enhancement on the gadolinium contrast image.
Tumor specimen showing the pinkish white color, soft, friable nature of the tumor
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F2
Just beneath the laminae a vascular, pinkish white, friable, soft mass found [Figure 2] completely carpeting the cord from all sides.
(a) Routine staining show pleomorphic, large cells with abundant cytoplasm (arrowhead) with large numbers of lymphocytic infiltrate (long arrow). (b) Numerous mitotic figures (arrow). (c) Tumor giant cells (arrow). (d) Emperipolesis: Phagocytosis of red cells, leukocytes and tumor cells by the histiocyte
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F3
Histopathology showed sheets of large, pleomorphic, mononuclear cells showing marked cytologic atypia admixed with large no of lymphocytes [Figure 3a]. Cells were large epithelial like with abundant pale eosinophilic cytoplasm with oval to irregular nuclei, vesicular chromatin, prominent nucleoli with numerous mitotic figures [Figure 3b]. There were binucleate and multinucleated giant cells [Figure 3c]. Few areas showing phagocytosis of red cells, leukocytes, and tumor cells by the histiocytes called emperipolesis [Figure 3d] were seen.
Immunohistochemistry with S-100 positivity
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F4
S-100 [Figure 4], CD68 [Figure 5], and particularly lysozyme [Figure 6] and was negative for CD1a, CD21, langerin suggesting the final diagnosis as histiocytic sarcoma. Staining for myeloperoxidase, CD34, and CD117 were negative excluding myeloid sarcoma.
CD68 immunopositivity
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F5
S-100 [Figure 4], CD68 [Figure 5], and particularly lysozyme [Figure 6] and was negative for CD1a, CD21, langerin suggesting the final diagnosis as histiocytic sarcoma. Staining for myeloperoxidase, CD34, and CD117 were negative excluding myeloid sarcoma.
Lysozyme immunopositivity
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F6
S-100 [Figure 4], CD68 [Figure 5], and particularly lysozyme [Figure 6] and was negative for CD1a, CD21, langerin suggesting the final diagnosis as histiocytic sarcoma. Staining for myeloperoxidase, CD34, and CD117 were negative excluding myeloid sarcoma.