Diagnosis and Discussion:
Electron microscopy resolved the problem of an unknown primary
tumor for this neck mass. Despite the suggestion of epithelial
differentiation for this tumor by light microscopy, electron microscopy
showed the complete lack of epithelial characteristics ultrastructurally.
The cellular features were those of a non-Hodgkin's lymphoma,
in this case the immunoblastic variant. The microvillus-like
processses further characterized the lesion as one of the rare
anemone (villiform) tumors, some of which have developed
in lymphomas (1-3). Additional Immunohistochemistry following
the EM diagnosis confirmed this as a malignant lymphoma with lambda
light chain restriction (Figs. 6 and 7). EMA can be expressed
in certain non-Hodgkin's lymphomas and mislead as is seen in the
present case.
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| Figure 6. Antibody to lambda light chain. | Figure 7. Antibody to kappa light chain. |
One of suggested deterrents for doing an ultrastructural investigation has been cost, with the inference that immunohistochemistry is cheaper. This type of case shows how incorrect this assumption can be. During the investigation of the second biopsy, immunostains were performed to the following markers; actin, AE1/AE3, desmin, vimentin, CEA, EMA, PLAP, lysozyme, alpha1-antichymotrypsin, alpha1-antitrypsin, common leukocyte antigen, UCHL-1, BerH2, IgA, IgM, IgG, kappa chain, and lambda chain. A total of 35 immunostained slides were prepared. In Ontario, for example, the cost of the technical component for the immunohistocehmistry would be $600.00. The cost of the technical component for the single EM examination is decidedly more economical at $135.00. And cost-effective, as it made the diagnosis!
References:
