This 60-year-old immunocompromised patient presented with a one-week history of progressive right-sided weakness, difficulty concentrating, and impaired word finding ability. Brain MRI showed a 5.5 x 4.0 x 2.7 cm, T2 and FLAIR hyperintense, T1 hypointense, non-contrast enhancing mass involving the white matter of the right frontal lobe.
Based on Figures #1 – #4, what stain would you like to perform to further evaluate this patient’s mass lesion?
A. Polyomavirus IHC
B. IDH1 R132H IHC
C. Cytokeratin IHC
D. AFB stain
This high power image shows scattered macrophages (small arrows) and several atypical glial cells with enlarged nuclei which have their chromatin pushed to the periphery of the nucleus by relatively homogenous glassy blue material (larger arrows). Note the background neuropil and frequent macrophages.
This low power image of a Luxol-Fast-Blue histochemical preparation (myelin stain) shows areas of white matter with preserved blue-staining myelin, and a large area with absent to pale myelin staining.
This medium power image of a Bielschowsky silver preparation (axon stain) shows some preservation of axons (thread-like dark staining structures) in the areas that show loss of myelin staining with LFB-PAS.
The proliferative activity as indicated by KI67 is increased.
The immunohistochemical stain for polyomavirus highlights the nuclei of many glial cells, including the atypical forms seen on H&E. This antibody reacts to SV40, BK and JC polyomavirus.
Answer: Polyomavirus IHC
Given the presence of morphologic changes of a demyelinating lesion and oligodendrocytes with intranuclear viral cytopathic change, performing a polyomavirus immunohistochemical stain to detect JC virus is the correct choice.
JC virus is the causative agent for Progressive Multifocal Leukoencephalopathy (PML). Please see additional Reference(s) / additional reading.
The nuclear atypia and elevated proliferative fraction, may be mistaken for a neoplastic process.
Reference(s) / additional reading:
Berger JR, Aksamit AJ, Clifford DB, Davis L, Koralnik IJ, Sejvar JJ, Bartt R, Major EO, Nath A. PML diagnostic criteria: consensus statement from the AAN Neuroinfectious Disease Section. Neurology. 2013 Apr 9;80(15):1430-8. doi: 10.1212/WNL.0b013e31828c2fa1. PMID: 23568998; PMCID: PMC3662270.
Atkinson AL, Atwood WJ. Fifty Years of JC Polyomavirus: A Brief Overview and Remaining Questions. Viruses. 2020 Sep 1;12(9):969. doi: 10.3390/v12090969. PMID: 32882975; PMCID: PMC7552028.
Zu Rhein GM. Ultrastructural studies in progressive multifocal leukoencephalopathy, a demyelinating disease of man of probable viral etiology. Int Arch Allergy Appl Immunol. 1969;36:Suppl:463-87. PMID: 4313668.
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