PMC8326103_01
CT myelogram showing T8/9 lobulated mass that appeared to be intradural, extramedullary, presumed to be superior disc extrusion versus intradural meningioma or nerve sheath tumor.
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F1
The mass resulted in moderate to severe left-sided central canal stenosis contouring and displacing the cord to the right of midline [Figure 1].
Intraoperative view of intramedullary portion of thoracic tumor.
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F2
The mass was originating within the cord parenchyma and had extruded out of the left lateral border of the spinal cord into the intradural, extramedullary space [Figure 2].
Histopathology. (a) Hematoxylin and eosin (H&E) stain, x40 and (b) x20 showing a solid proliferation of atypical epithelioid cells with scattered pigmented melanophages amidst fibroconnective tissue. The samples are richly cellular with round to ovoid nuclei and prominent nucleoli. There are areas of necrosis with associated inflammation and hemorrhage. (c) Few spindle-shaped nests of cells admixed with melanophages were noted, x40. (d) Ki-67 (MIB-1) index seen to be 1.5% with all other areas on x40 found to be <4%. (e) HMB45/ Tyrosinase/MART-1 immunoperoxidase stain diffusely positive, x40. (f) S-100 immunoperoxidase stain negative with interspersed dusty brown melanin pigment, x40.
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F3
Repeat analysis confirmed morphological and immunohistochemical features further supporting intermediate-to-high-grade primary meningeal melanocytoma versus melanoma [Figure 3].