Xanthomas

Question 1

Classification

Answer 1

Subcut lipid deposits

All xanthomas contain “foam cells” - macrophages laden with cholesterol and cholesterol esters

Secondary to lipid metabolism vs histiocytic disorders

Xanthomas secondary to lipid metabolism:

TENDON XANTHOMA

TUBEROUS XANTHOMA
Tubero-eruptive xanthoma

ERUPTIVE XANTHOMA

DYSLIPIDAEMIC PLANE XANTHOMA
Xanthelasma
Plane Xanthoma
Palmar xanthoma

Question 2

Tendon xanthoma

Answer 2

CLINICAL FEATURES
Subcut nodules/papules in relation to tendons
Most commonly attached to extensor tendons over knuckles, achilles, other tendons
Can be moved from side to side
If involves periosteum of the patellar tendon —> fixed
Accumulation of cholesterol is Depp within tendons —> Overlying skin not yellow
Contains collagen + foamy macrophages —> feels hard

ASSOCIATIONS
Familial hypercholesterolaemia
Secondary hypercholesterolaemia in prolonged cholestasis
Cerebrotendinous xanthomatosis (no hypercholesterolaemia)
Sitosterolaemia (no hypercholesterolaemia)

IX
Full lipid profile (familial hypercholesterolaemia—> raised T. Cholesterol, LDL, normal triglycerides)
LFT (cholestasis)

MX
cholesterol reduction with statins

PROGNOSIS
Sometimes improve with cholesterol reduction, but don’t tend to completely resolve
Pain improves with LDL reduction

Question 3

Tuberous xanthoma

Answer 3

CLINICAL FEATURES
Firm yellow, red nodules over sites of pressure 
- Commonly on extensors of elbows, knees
- Heels
- Plantar surfaces feet
- Bone marrow
Painless
Can be itchy 
susceptible to trauma given location 
Tubero-eruptive xanthoma = central tuberous Xanthoma surrounded by smaller lesions 

ASSOCIATIONS
Combined dyslipidaemia esp type III familial dysbetalipoproteinamia

IX
Full lipid profile (combined dyslipidemia —> raised T. Cholesterol, LDL, triglycerides +/- reduced HDL)

MX
Rx of combined dyslipidaemia

PROGNOSIS
good response to Rx

Question 4

Eruptive Xanthoma

Answer 4

CLINICAL FEATURES
Multiple small yellow papules arising on erythematous base
Large numbers over extensor surfaces esp buttocks, back, arms, legs
Itchy
Foamy macrophages with triglycerides in addition to cholesterol
Lipaemic appearance of blood/serum
Creamy yellow colour of retinal blood vessels —> lipaemia retinalis

ASSOCIATIONS
Any cause of hypertriglyceridaemia -
- familial/primary
- secondary —> diabetes, CRF, ETOH, retinoids, OCP, pregnancy, paraproteinaemia

IX
Full lipid profile (hypertriglyceridaemia —> raised triglycerides > T. Cholesterol, reduced HDL)
Fasting glucose, OGTT (diabetes)

MX
Triglyceride reduction

PROGNOSIS
Resolve within 2 weeks of normalisation of triglyceride levels

Question 5

Dyslipidaemic plane Xanthoma - Xanthelasma

Answer 5

Plane Xanthomas that develop around the eyes “ xanthelasma palpebrum”
Commonly affect upper eyelids, area around medial canthus
Pale yellow to yellow orange

ASSOCIATIONS
Primary - Familial hypercholesterolaemia
Primary - Type III combined dyslipoproteinaemia
Secondary - Chronic cholestasis 
Normal lipid levels 

COMPLICATIONS
coronary heart disease

IX
Full lipid profile (familial hypercholesterolaemia —> raised T. Cholesterol, LDL; combined dyslipoproteinaemia —> raised T.cholesterol, LDL, triglycerides +/- reduced HDL)
LFT (chronic cholestasis)

MX 
TCA
Silver nitrate
Electrocautery
Excision
Ablative laser
If LDL high —> statin to lower LDL —> regression of Xanthelasma without need for other intervention 

PROGNOSIS
Often recurs after Rx

Question 6

Dyslipidaemic plane xanthoma - plane xanthoma

Answer 6

Flat smear-like lesions
Occur anywhere

ASSOCIATIONS
Homozygous Familial hypercholesterolaemia —> interdigital plane Xanthomas affecting webspace between 1st and 2nd fingers

DDX
Diffuse plane normolipidaemic xanthomatosis (rare form of histiocytosis) often assoc with paraproteinaemia/underlying systemic haem/lymphoproliferative disease —> normal lipids
Necrobiotic Xanthogranuloma (rare chronic progressive histiocytosis) —> assoc with haem malignancy

IX
Full lipid profile (familial hypercholesterolaemia —> raised T. Cholesterol, LDL)
SPEP + immunofixation (paraproteinaemia)
Autoimmune screen
\+/- skeletal survey
\+/- BMAT

MX
Reduce hypercholesterolaemia

PROGNOSIS
Good response to Rx

Question 7

Dyslipidaemic plane xanthoma - palmar xanthoma

Answer 7

Orange yellow lipid deposition running in palmar creases “xanthomatosis striata palmaris”
+/- flexor creases of the wrists

ASSOCIATIONS
Pathognomonic of type III combined dysbetalipoproteinaemia

IX
Full lipid profile (type III combined dyslipoproteinaemia —> raised T.cholesterol, LDL, triglycerides +/- reduced HDL)
Fasting glucose, OGTT (diabetes)
UEs (nephrotic syndrome)
LFTs (liver disease)
TSH (hypothyroidism)

MX
Rx of combined dyslipoproteinemia

PROGNOSIS
Good response to Rx