case_images: PMC9282790_01
case_images: Noncontrast CT showing 15 mm thick left-sided subdural hematoma with the rightward midline shift.
case_images: SNI-13-267-g001.jpg
case_images: PMC9282790_01_SNI-13-267-g001.jpg
case_images: F1
case_images: Approximately 10 days later, follow-up CT head showed evidence of rebleeding with an interval increase in the size of the left subdural hematoma to 15 mm and an increase in the rightward midline shift to 8 mm [Figure 1].
case_images: H&E x100, EMH with erythroid islands (a) and immature mononuclear cells (b).
case_images: SNI-13-267-g002.jpg
case_images: PMC9282790_01_SNI-13-267-g002.jpg
case_images: F2
case_images: On microscopic examination, there were several small clusters of cells with the appearance of erythroid islands and immature mononuclear cells noted within the membranes [Figures 2a and b].
case_images: (a) H&E x400: Large cluster of plasma cells, (b) CD138 x400: Cells are positive for CD138, (c) Kappa x100: Cells are positive for kappa IHC staining, and (d) lambda x100: Cells are negative for lambda IHC staining.
case_images: SNI-13-267-g003.jpg
case_images: PMC9282790_01_SNI-13-267-g003.jpg
case_images: F3
case_images: In addition, in one tissue block, there was a cluster of cells morphologically resembling plasma cells [Figure 3a]. IHC staining for CD138 and cytoplasmic kappa and lambda light chain [Figures 3b-d] revealed this to be a cluster of kappa-restricted plasma cells suggestive of a small extraosseous plasmacytoma.
case_images: PMC9282790_02
case_images: (a) Noncontrast CT showing bilateral subdural hematomas with leftward midline shift, (b) H&E x400: Perivascular erythroid islands, and (c) E-cadherin x400: e-cadherin stains immature erythroid precursors.
case_images: SNI-13-267-g004.jpg
case_images: PMC9282790_02_SNI-13-267-g004.jpg
case_images: F4
case_images: The patient's primary care physician obtained imaging of the brain which showed bilateral subacute-on-chronic subdural hematomas with 6 mm of the leftward midline shift [Figure 4a]. On microscopic examination, there were several erythroid islands noted [Figure 4b] which were highlighted by IHC staining for E-cadherin [Figures 4c]; in addition, there were rare megakaryocytes [Figure 5a] which were highlighted by CD61 [Figure 5b], respectively, supporting the presence of multiple foci of EMH within the subdural hematoma.
case_images: (a) H&E x400: Erythroid islands and a possible megakaryocyte and (b) CD61 x400: Highlights a megakaryocyte.
case_images: SNI-13-267-g005.jpg
case_images: PMC9282790_02_SNI-13-267-g005.jpg
case_images: F5
case_images: On microscopic examination, there were several erythroid islands noted [Figure 4b] which were highlighted by IHC staining for E-cadherin [Figures 4c]; in addition, there were rare megakaryocytes [Figure 5a] which were highlighted by CD61 [Figure 5b], respectively, supporting the presence of multiple foci of EMH within the subdural hematoma.