Spleen Fx Diffuse Non Enhancement | Adrenal Nodule Dx Amyloidosis CT 72M history of systemic amyloidosis

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Spleen


 

2. Findings and Diagnosis


15479 This is a CT scan of the adrenal with findings that include a nodule in the left adrenal. The lack of perfusion in the spleen was shown at autopsy to be due to diffuse infiltration of amyloid in this patient with amyloidosis. (see 15349 -52) Courtesy Ashley Davidoff MD. infiltrative

Page 2 – Findings and Diagnosis (Fx and Dx)

Under-Image Caption (Three-Paragraph Format)

Diffuse Splenic Non-Enhancement in Amyloidosis
CT shows diffuse hypoattenuation of the spleen, consistent with non-enhancement in the setting of systemic amyloidosis.
Courtesy: Ashley Davidoff MD, TheCommonVein.com (15479)

Table 1 – U-SSPCT–C Analysis

Parameter Description
Units (U) Spleen (primary unit), adrenal gland (secondary finding)
Size Spleen normal to slightly enlarged; adrenal nodule ~1.5 cm
Shape Spleen: smooth; adrenal: round
Position LUQ (spleen); right adrenal superior to kidney
Character Diffuse non-enhancement of spleen; adrenal is solid and mildly hyperdense
Time Chronic pattern suspected (systemic amyloidosis)
Connections Spleen: part of lymphatic and immune system; adrenal: endocrine system
Clinical Context Patient with known amyloidosis; systemic infiltration likely

Table 2 – Differential Diagnosis

Table 2a – Most Likely Diagnosis

Diagnosis Rationale
Amyloidosis Known systemic disease; characteristic non-enhancing spleen; adrenal involvement common

Table 2b – Other Considerations (IINMTM–CIIIIFPP)

Category Example Diagnosis Why Considered
Inflammatory / Immune Sarcoidosis Non-caseating granulomas may infiltrate spleen
Infection Tuberculosis May affect spleen in disseminated form
Neoplasm – Malignant (Primary) Lymphoma Common cause of diffuse splenic infiltration
Neoplasm – Malignant (Metastatic) Melanoma May spread to spleen and adrenal
Trauma Splenic infarction Rare but mimics non-enhancement
Metabolic Gaucher’s Disease Infiltrative pattern, hepatosplenomegaly
Circulatory Splenic infarcts Hypoperfused spleen
Inherited Sickle Cell Functional asplenia from infarction

Table 3 – Imaging Diagnosis: Strategies and Guidelines

Imaging Modality Use in Diagnosis When / Why Used Guideline / Reference
CT (Contrast) Evaluates enhancement, infarction, infiltration First-line for hypoattenuating spleen ACR Appropriateness Criteria®: Splenomegaly or Splenic Mass
https://acsearch.acr.org/list/GenerateAppendixPDF?TopicId=130
MRI Superior for tissue characterization, vascularity, infiltration Follow-up for CT, or first-line in younger/renal-risk patients Radiology White Paper: Infiltrative Disease Imaging
https://www.jacr.org/article/S1546-1440(13)00305-0/abstract
Ultrasound Assesses size, echotexture, splenic contour First-line for splenomegaly or incidental findings AIUM Practice Parameters
https://www.aium.org/resources/practice-parameters
Nuclear Medicine Functional studies (e.g., colloid scan for splenic activity) Rarely used; for infarct or asplenia suspicion SNMMI Guidelines: Liver and Spleen Scintigraphy
https://www.snmmi.org/Web/Web/Clinical-Practice/Procedure-Standards
Image-Guided Biopsy Diagnostic confirmation (e.g., amyloid, lymphoma) Reserved for unclear/inconclusive imaging or to guide treatment SIR Guidelines: Image-Guided Biopsy
https://www.sirweb.org/in-practice/guidelines-and-statements/

3. Clinical


Page 4 – Clinical (Diagnosis-Focused: Systemic Amyloidosis with Splenic Involvement)

Domain Details
Diagnosis Systemic Amyloidosis (AL or AA types) with splenic involvement
Etiology Misfolded protein deposition — AL (light chain from plasma cell dyscrasia), AA (serum amyloid A from chronic inflammation/infection)
Structural Change Amyloid replaces splenic tissue, leading to decreased vascularity, infarction, possible size changes
Functional Change Loss of immune filtering, increased infection risk, possible cytopenias due to splenic sequestration
Clinical Features Fatigue, weight loss, splenomegaly, cytopenias, nephrotic syndrome, macroglossia, periorbital purpura
Key Lab Tests CBC (cytopenias), SPEP/UPEP (monoclonal spike), Free light chains (kappa/lambda ratio), Biopsy (Congo red positivity, apple-green birefringence)
Treatment Strategies AL: Chemotherapy (bortezomib-based); AA: Treat underlying cause. Supportive care includes vaccines and organ-directed therapies
Risk Considerations Functional asplenia (infection risk), renal failure, cardiac amyloidosis, bleeding tendencies

4. Historical and Cultural


Page 5 – History, Culture, and Art

1. History of Disease Recognition

Aspect Details
First Descriptions Term “amyloid” coined by Rudolf Virchow in 1854, mistakenly thought to be starch-like.
Clarification Later confirmed to be proteinaceous in origin, not carbohydrate.
Early Observations Involved organs like the liver, spleen, and kidney in patients with chronic infections.

2. History of Diagnosis

Aspect Details
Congo Red Stain Introduced in early 20th century; apple-green birefringence under polarized light became the gold standard.
Biopsy Sites Fat pad aspiration and organ-specific biopsies became common.
Recent Advances Mass spectrometry used to subtype amyloid fibrils.

3. History of Imaging

Modality Relevance
CT Shows non-enhancing or hypoattenuated spleen due to loss of perfusion.
MRI May show low signal on all sequences; delayed enhancement.
Radionuclide Scans SAP scintigraphy used in Europe to track amyloid burden (limited availability).

4. History of Laboratory Testing

Test Evolution
SPEP/UPEP Became standard for detecting monoclonal light chains.
Free Light Chain Assay Developed to improve sensitivity and specificity in plasma cell disorders.

5. History of Treatment

Era Approach
Pre-2000 Supportive care only; poor prognosis.
2000s Use of chemotherapy borrowed from myeloma (melphalan, dexamethasone).
2010s–Present Proteasome inhibitors (e.g., bortezomib), stem cell transplantation, and novel biologics.

6. Cultural Meaning and Symbolism

Theme Interpretation
Invisibility Amyloidosis is often termed a “zebra” due to its rarity and hidden nature.
Crystal and Stiffness Symbolic of rigidity and fragility, as amyloid infiltrates solidify soft organs.

7. Artistic Representation

Medium Example
Microscopic Imaging Congo red birefringence under polarized light has become an iconic educational image in pathology.
Medical Illustration Organ cross-sections with waxy deposition shown in autopsy texts and anatomy atlases.

8. Notable Figures

Person Role
Rudolf Virchow Coined the term “amyloid”; key figure in cellular pathology.
Sir Mark Pepys Leading researcher in SAP imaging and amyloidosis treatment.

9. Quotes

Quote Author
“Diseases of the spleen often whisper before they scream.” Attributed to 20th century internists – common in internal medicine lore

 

5. MCQs


✅ MCQ 1 – Basic Science

Which of the following stains is most characteristic for confirming amyloid in tissue samples?

A. PAS
B. Congo red
C. Masson trichrome
D. Giemsa

Correct Answer Explanation
B. Congo red Congo red binds amyloid fibrils, showing apple-green birefringence under polarized light – diagnostic hallmark.
Incorrect Option Why Incorrect
A. PAS Stains glycogen and mucopolysaccharides, not specific to amyloid.
C. Masson trichrome Differentiates collagen (blue/green) and muscle, not used for amyloid.
D. Giemsa Used for blood cells and microbes; not amyloid-specific.

✅ MCQ 2 – Basic Science

Amyloidosis primarily involves which of the following abnormal protein conformations?

A. Alpha-helix
B. Beta-pleated sheet
C. Triple helix
D. Random coil

Correct Answer Explanation
B. Beta-pleated sheet Amyloid fibrils adopt beta-pleated sheet conformation, leading to abnormal aggregation.
Incorrect Option Why Incorrect
A. Alpha-helix Normal structure of many proteins, not pathological in amyloidosis.
C. Triple helix Structure of collagen, unrelated to amyloid.
D. Random coil Lacks stable secondary structure, not associated with amyloid.

✅ MCQ 3 – Clinical

Which systemic complication is most commonly associated with AL amyloidosis?

A. Hemorrhagic stroke
B. Nephrotic syndrome
C. Diabetes insipidus
D. Hypocalcemia

Correct Answer Explanation
B. Nephrotic syndrome AL amyloid commonly deposits in glomeruli, disrupting filtration → proteinuria and hypoalbuminemia.
Incorrect Option Why Incorrect
A. Hemorrhagic stroke Rare in amyloidosis.
C. Diabetes insipidus More common in hypothalamic or pituitary disease.
D. Hypocalcemia Unrelated unless kidney damage is extreme.

✅ MCQ 4 – Clinical

Which of the following therapies is most appropriate for AL amyloidosis?

A. Antibiotics
B. Bortezomib
C. Insulin
D. Statins

Correct Answer Explanation
B. Bortezomib A proteasome inhibitor used to reduce plasma cell dyscrasia driving light chain production.
Incorrect Option Why Incorrect
A. Antibiotics Not first-line unless secondary infection.
C. Insulin Not relevant to amyloid pathology.
D. Statins Treat lipids, not protein misfolding.

✅ MCQ 5 – Radiologic

Which imaging feature is most characteristic of splenic involvement in systemic amyloidosis?

A. Hypodense non-enhancing spleen on CT
B. Splenic calcification on X-ray
C. Diffuse increased FDG uptake on PET
D. Enlarged spleen with fat stranding

Correct Answer Explanation
A. Hypodense non-enhancing spleen on CT Reflects reduced perfusion due to amyloid infiltration.
Incorrect Option Why Incorrect
B. Splenic calcification Nonspecific; not typical for amyloid.
C. Increased FDG uptake Amyloid often shows decreased metabolic activity.
D. Fat stranding More typical of inflammation, not amyloidosis.

✅ MCQ 6 – Radiologic

What nuclear medicine technique is used to track systemic amyloid deposits?

A. Technetium-99m MIBI
B. Iodine-131 MIBG
C. Serum amyloid P component (SAP) scintigraphy
D. Gallium-67 scan

Correct Answer Explanation
C. SAP scintigraphy Binds selectively to amyloid deposits, used for staging and follow-up in some centers.
Incorrect Option Why Incorrect
A. Tc-99m MIBI Used in myocardial perfusion imaging.
B. I-131 MIBG For neuroendocrine tumors, not amyloid.
D. Gallium-67 Inflammatory conditions, not specific to amyloid.

✅ MCQ 7 – Radiologic

Which CT pattern suggests adrenal amyloid involvement?

A. Hyperenhancing adrenal nodule
B. Fat-containing lesion with calcifications
C. Non-enhancing hypodense mass
D. Enhancing lesion with central necrosis

Correct Answer Explanation
C. Non-enhancing hypodense mass Amyloid deposits cause poor perfusion and hypoattenuation.
Incorrect Option Why Incorrect
A. Hyperenhancing lesion Suggests pheochromocytoma or adenoma.
B. Fat and calcifications Suggests myelolipoma.
D. Central necrosis More typical of carcinoma or metastasis.

6. Memory Image


Page 7 – Memory Image Table

Component Description
Visual Metaphor Title “The Frozen Sponge”
Conceptual Image A once-vibrant red sponge (symbolizing the spleen) now frozen in translucent crystalline layers, resting dry and colorless beside a dull river of stalled blood.
Anatomy Representation The sponge = spleen; the splenic architecture is normally porous, dynamic, and richly vascularized.
Physiologic Meaning A functioning spleen filters blood, removes pathogens and senescent cells — a living immune sponge.
Pathologic Interpretation In amyloidosis, the “freeze” represents amyloid infiltration. Protein deposits harden the sponge, cutting off blood flow — hence the visual of a frozen, non-perfused organ.
Imaging Parallel On CT, the spleen shows diffuse hypoattenuation (non-enhancement), as if perfusion is literally frozen in time.
Emotional/Memory Hook The transformation from living filter to lifeless ice reinforces the concept of functional loss due to infiltration — frozen structure, frozen function.
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Challenge

2. Findings and Diagnosis

3. Clinical

4. Historical and Cultural

5. MCQs

6. Memory Image

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