Clayton Wiley MD/PhD

38-year-old male with progressive weakness of upper and lower extremities, in addition to confusion. Describe the MRI findings (location, enhancement, mass effect).

MRI T2 FLAIR images

MRI T1 pre and post contrast

MRI side-by-side FLAIR and postcontrast images

Question 1 What additional clinical information would you like to know?

Is there any significant past medical history? signs/symptoms of infection previous malignancy (Fam Hx) Previous treatments PE- evidence of peripheral lesions or infections? Lab- Blood and CSF analysis Answer

Give a differential diagnosis based on MRI. Question 2

Infectious disease (Toxoplasmosis, Amebic encephalitis, Viral, PML) Lymphoma Demyelinating lesion (Multiple sclerosis) Metastasis Gliomatosis cerebri Multiple infarcts (Embolic / Vasculopathy) Answer

The surgeon tells you that a full body CT showed no masses, an HIV test was positive and the CSF showed lymphocytes. You receive 2 cores of tissue in consultation for intraoperative guidance. Describe the cytologic features of the touch prep and smear. Click here to view slides.here Question 3

What is your intraoperative diagnosis? Question 4

What can a neuropathologist do to validate their diagnosis? Question 5

LCA, CD20/L26 & CD3. Other hematopoietic markers (ie CD79a, kappa, lambda, CD10, MUM-1, etc) and vimentin/GFAP (to highlight gliosis) might also be helpful in certain cases. Answer

Review the permanent section and describe the microscopic features. Click here to view slide.here Question 6

What is your final diagnosis? Question 7

Secondary involvement by lymphoma is most common in what part of the CNS? Question 8

Dura / leptomeninges Answer

What are some diseases associated with PCNSL? Question 9

HIV infection Immunosuppressive therapy (post transplantation) Hodgkin's disease Epstein-Barr virus Primary immunodeficiency syndromes: Wiskott-Aldrich, X- linked lymphoproliferative, Severe combined immunodeficiency, Ataxia-telangiectasia Answer