Radiology and Pathology Teaching Points

Sessions III and IV

Pat Hudgins and Dan Brat

III.1: Sacramentum Gladiatorium

Processes in sphenoid sinus can affect the orbit/visual pathways

III – Case 1

Meningeal enhancement around inflammatory processes is common

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

Volume loss is hard to quantify

• Corpus callosal thinning

• Vermian atrophy

• Medullary atrophy

III – Case 2

WM changes in unusual places

• Temporal horns and sweeps

III – Case 2

WM changes symmetric

• Int/ext capsule, both frontal and occipital

III – Case 2

Polyglucosan bodies accumulate in the central and peripheral nervous systems and are often associated with glycogen branching enzyme (GBE) deficiency

(PAS)-positive polyglycosan bodies within the neuropil of the basal pontine gray matter (arrow).

A. Teased-fiber from sural nerve with axonal enlargements due to polyglucosan bodies. B. Semithin section shows axonal accumulations of glycogen deposits.

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

Initial MRI

• Volume loss is common, hard to quantify

III – Case 3

Initial MRI 7 months laterIII – 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

Infinite gray scale options mean images can be displayed in weird ways

III – Case 4

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

FLAIR T2 FFE

III – Case 5

III – Case 5

FLAIR Sag

III – Case 5

Volumetric imagesObtained 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

T1 is so good, why put on fat sat?

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.

Microadenoma is usually focal and discrete

IV– Case 2

More than an adenoma can occur in the pituitary gland

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

Whenever there are multiple opinions re:

Hydrocephalus or

Leptomeningeal enhancement:

The next steps should be…

1)Lumbar puncture

2)Ophthalmoscopic exam

IV – Case 3

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

Yes, it had long T1 and T2, but…IV – Case 4

there were some hints…..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.

DDx for dural enhancement is long

1) Normal dura• Post-op

2) Edematous dura• Post-LP

3) Invaded dura• Granulomatous disease• Infection• Meningioma• Hemangiopericytoma• Mets

IV – Case 5

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

IgG4IgG

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

Thank You !