Pat Hudgins and Dan Brat

III.1: Sacramentum Gladiatorium

III – Case 1

III – Case 1

Mucocele with superimposed bacterial infection
Always send cultures if disease could be infectious. Stains would not have revealed the type of organism or therapeutic resistance.

III.2: Diabetes Does Not Explain it All

III – Case 2
• Corpus callosal thinning
• Vermian atrophy
• Medullary atrophy

III – Case 2
• Temporal horns and sweeps

III – Case 2
• Int/ext capsule, both frontal and occipital

Polyglucosan bodies accumulate in the central and peripheral nervous systems and are often associated with glycogen branching enzyme (GBE) deficiency
A. Teased-fiber from sural nerve with axonal enlargements due to polyglucosan bodies.
B. Semithin section shows axonal accumulations of glycogen deposits.
(PAS)-positive polyglycosan bodies within the neuropil of the basal pontine gray matter (arrow).

III.3: Double Vision? … Give Your Head a Shake

III – Case 3
• Volume loss is common, hard to quantify

III – Case 3

Testicular germ cell tumors occasionally regress spontaneously (estimated at 4%) and may manifest later by autoimmune or metastatic disease.
Anti-CRMP5 paraneoplastic disease more often includes cerebellar ataxia, chorea, and ocular manifestations
Pathology of active paraneoplastic cerebellar encephalitis consists of a T-cell infiltrate, generally directed at
Purkinje cells.

III.4: Clues Hidden in the Skin

III – Case 4
Infinite gray scale options mean images can be displayed in weird ways

Chediak-Higashi syndrome is caused by mutations in the LYST gene.
Enlarged, dysfunctional lysosomes in neutrophils prevent appropriate immune responses
Amyloid deposits (SAA type) reflect widespread acute inflammation

III.5: Spots, spots everywhere, and not a spot to see

III – Case 5

III – Case 5

III – Case 5
Obtained in one plane, others are reformats

RMSF is caused by Rickettsia rickettsii , a species of bacterium that is spread to humans by Dermacentor ticks
Serology for IgG is most common laboratory test;
Immunohistochemistry and PCR are also possible.

Session III: What have we learned?
• Put sphenoid sinus/central skull base on your checklist
• Volume loss is like pornography: you know it when you see it, but no good definition
• A good Radiology Dept standardizes gray scale display

Session III: What have we learned?
• Paraneoplastic disease can be the first manifestation of neoplastic disease and is due to antibody-mediated immune response to neuronal antigens.
• Genetic diagnosis of rare diseases (polyglucosan body disease; Chediak-Higashi) is becoming more frequent; the pathology remains important to understand.
• Serology for IgG is most common laboratory test for
RMSF

IV.1: Raise Your Grade Point Average

IV – Case 1

Granulomatosis with Polyangiitis (GPA) (Wegener ’ s granulomatosis) is a NECROTIZING ANGIITIS with……
……Granulomatous Inflammation (to distinguish from
Microscopic polyangiitis)
The active vasculitic disease can be difficult to find, but the necrosis and granulomatous inflammation are abundant.

IV – Case 2

IV – Case 2

Pathologist ’ s favorite saying: “ when there is an issue, get some tissue!!
”
Tissue-based diagnosis in this case would not have been definitive, most likely….
….but it would have ruled out adenoma before radiation.
Not all sellar lesions associated with increased prolactin levels are adenomas.
Adenoma Wegener ’ s Granulomatosis

IV.3: Admissions Ad Nauseum:
A Cryptic Case of Chiasmopathy

IV – Case 3
Hydrocephalus or
Leptomeningeal enhancement:
The next steps should be…
1)Lumbar puncture
2)Ophthalmoscopic exam

Cryptococcal organisms (budding ovoid yeast forms) have a thick mucoid capsule that can be seen with mucicarmine. Also seen on silver stains.
The degree of inflammation may be low in immunocompromised patients.
Immune reconstitution (IRIS) associated with cryptococcus in AIDS patients can lead to abrupt and severe symptoms.

IV.4: A case of Mistaken Identity

IV – Case 4

IV – Case 4
↑ Vascularity Necrosis

High grade gliomas in children are fatal diseases, like adults, but have distinctive sites, molecular profiles and mutations.
The presence of necrosis would qualify this case as a glioblastoma, WHO grade IV.
The most frequent congenital brain tumors are teratomas, astrocytomas, PNETs and choroid plexus papillomas.

IV.5: OMG, I can't C.

IV – Case 5
1) Normal dura
• Post-op
2) Edematous dura
• Post-LP
3) Invaded dura
• Granulomatous disease
• Infection
• Meningioma
• Hemangiopericytoma
• Mets

Mass-forming lesions due to lymphoplasmacytic infiltrates and sclerosis, a raised serum IgG4 level and increased IgG4+ plasma cells in the involved tissues.
The understanding of IgG4-Related Sclerosing
Disease is still evolving.
Would have been called “ inflammatory pseudotumor ”
“ hypertrophic pachymeningitis ” prior to IgG4-RD
IgG IgG4

Session IV: What have we learned?
• Don’t put fat sat on T1, you lose the advantages
• More than adenomas happen in the pituitary
• If you’re going to call a JPA, it shouldn’t be a vascular or necrotic mass
• Especially if a child is not NF-1, be very careful about calling a hypothalamic JPA
• Diff Dx for sick dura is really long

Session IV: What have we learned?
• Granulomatosis with Polyangiitis (Wegener’s granulomatosis) is an aggressive necrotizing angiitis; difficult to diagnose based strictly on histologic findings.
• “When in doubt, dig it out”
• IgG4-Related Sclerosing Disease is a newly described form of inflammatory pseudotumor with elevated serum IgG4 level and IgG4+ plasma cells in tissues….still evolving
• Midline enhancing masses in childhood can be due to low or high grade astrocytomas; the presence of necrosis suggests a glioblastoma, WHO grade IV