PMC2913787_01
MRI of the neck showing an enlarged lymph node (long arrow) and a bulge in the right tonsillar fossa (short arrow) suspicious for primary tumour.
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fig1
Due to a possible vascular relation to the mass, an MRI of the neck was done, showing a sharply defined ovoid 3 x 3 x 4.5 cm nonspecific soft tissue mass with heterogeneous enhancement, likely a lymph node, with a mass-like bulge in the right tonsillar fossa suspicious for a primary tumour (Figure 1).
Lymph node with diffuse infiltrate of plasma cells including atypical binucleated and multinucleated forms (black arrows) (H & E stain, x40).
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fig2
Binucleate and multinucleate forms were also present (Figure 2).
Tonsillar tissue with intact surface squamous epithelium (arrow) and underlying diffuse infiltrate of neoplastic plasma cells (H & E stain, x10).
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fig3
The tonsillar lesion was fairly circumscribed and the epithelium was not infiltrated (Figure 3).
CD138 immunostain was positive, confirming plasma cells (x40).
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fig4
Further immunohistochemical analysis on the specimens showed CD138 plasma cell marker positivity (Figure 4), while CD20 and CD3 were negative, with kappa light chain restriction.