PMC5467342_01
Morphologic features of the original dura/calvarium lesion. (a-c) H&E staining demonstrates a malignant spindle and epithelioid cell neoplasm with increased mitotic activity ((c), arrow) and necrosis (not shown). A large panel of immunostains, including markers of both epithelial and mesenchymal differentiation, was negative, except for focal expression of SMA (inset).
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fig1
Pathology revealed a malignant spindle and epithelioid cell neoplasm (Figure 1) that was focally positive for smooth muscle actin (SMA) and negative for multiple keratins, EMA, CD34, Desmin, GFAP, and S100 (see Table 1 for antibody information). In light of the kidney biopsy findings, the slides from the cranial/dural lesion were rereviewed, and a mixed epithelioid and spindle cell population was confirmed (Figure 1).
Morphologic and immunohistochemical features of the renal neoplasm support a diagnosis of diffuse large B-cell lymphoma. (a) H&E staining demonstrates an epithelioid neoplasm with a distinctive infiltrative pattern between renal tubules (nonneoplastic renal tubules highlighted by arrows). (b) An EMA immunostain is immunoreactive in the nonneoplastic renal tubules, but negative in the neoplasm. (c) A PAX8 immunostain is diffusely and strongly positive in both nonneoplastic renal tubules (red ovals) and the infiltrative neoplasm. (d-f) Subsequent LCA, PAX5/BSAP, and CD5 immunostains support the diagnosis of diffuse large B-cell lymphoma. Note the absence of PAX5 in nonneoplastic renal tubules (red ovals) and the presence of CD5 in nonneoplastic T-cell lymphocytes.
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fig2
A diagnostic biopsy of one kidney was performed which demonstrated an epithelioid neoplasm with a prominent infiltrative pattern between tubules (Figure 2(a)). Table 1 for antibody information) demonstrated that the neoplastic cells were positive for LCA (Figure 2(d)), CD20, PAX5/BSAP (Figure 2(e)), BCL6, and BCL2 (focal) and negative for CD3 and CD5 (Figure 2(f)). These findings confirmed the diagnosis of diffuse large B-cell lymphoma of follicular center cell derivation.
Reevaluation of the original dura/calvarium lesion is consistent with diffuse large B-cell lymphoma. (a-b) Immunostains for LCA and PAX8 were diffusely and strongly immunoreactive in the tumor, supporting the diagnosis of lymphoma. The presence of CD20 and the absence of CD3 in neoplastic cells were consistent with a lymphoma of B-cell lineage (CD3 is present in nonneoplastic T-cell lymphocytes).
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fig3
Subsequent immunostains on the dura specimen demonstrated the presence of PAX8, LCA, and CD20 and an absence of CD3 in both the spindle and the epithelioid cell components (Figure 3), confirming the diagnosis of diffuse large B-cell lymphoma, spindle cell variant.