Xanthomas

 Xanthelasma, eruptive, tuberous, tendinous, planar, plexiform






Etiology/Pathogenesis




• Associated with hereditary lipoproteinemias and occasionally secondary lipoproteinemias
• May also occur in normolipemic patients

image Particularly plexiform xanthoma


Clinical Issues




• Wide age range (children or adults)

• Usually occur in skin and subcutaneous tissue

• Occasionally arise in deep soft tissues (tendon, synovium, bone)

• Classified based on clinical features and gross appearance

• Treatment: Medical therapy or conservative excision

• Excellent prognosis


Microscopic




• Specific classification requires clinicopathologic correlation

• Sheets and aggregates of foamy macrophages

• Variable secondary changes including inflammation, giant cells, fibrosis, and cholesterol cleft formation

• Plexiform xanthoma features multinodular or plexiform growth pattern


Top Differential Diagnoses




• Localized-type tenosynovial giant cell tumor (giant cell tumor of tendon sheath)

• Solitary (juvenile) xanthogranuloma

• Lipidized-type dermatofibroma (fibrous histiocytoma)

• Verruciform xanthoma

• Plexiform fibrohistiocytic tumor

image
Xanthelasma
Xanthelasmas (and planar xanthomas) consist of a sheet-like infiltrate of foamy macrophages involving the dermis and surrounding adnexal structures. Small areas of chronic inflammation image may be present, but fibrosis and cholesterol clefts are not typical.


image
Eruptive Xanthoma
Eruptive xanthoma is characterized by sheets of macrophages within the dermis. Extravascular lipid deposits with a blue-gray amorphous appearance are often seen image between dermal collagen bundles. A sparse perivascular inflammatory infiltrate image can also be seen.

image
Early Eruptive Xanthoma
In contrast to other forms of xanthoma, the cells in eruptive xanthoma are nonfoamy in early lesions. Note the rare foamy macrophages image and extravascular lipid image.

image
Older Eruptive Xanthoma
Older eruptive xanthomas accumulate more foamy macrophages image and consist of a mixture of foamy and nonfoamy cells. Again, note areas of lace-like blue-gray extravascular lipid between the dermal collagen bundles image.


TERMINOLOGY


Synonyms




• Plexiform xanthomatous tumor (for plexiform xanthoma)


Definitions




• Reactive mass-forming collection of lipidized macrophages, usually resulting from altered serum lipid levels
image Several forms

– Xanthelasma

– Eruptive xanthoma

– Tuberous xanthoma

– Tendinous xanthoma

– Planar xanthoma

– Plexiform xanthoma


ETIOLOGY/PATHOGENESIS


Hereditary or Nonhereditary




• Associated with hereditary lipoproteinemias and occasionally secondary lipoproteinemias (e.g., diabetes, hypothyroidism, primary biliary cirrhosis)
• May also occur in normolipemic patients

image Particularly plexiform xanthoma


CLINICAL ISSUES


Epidemiology




• Age
image Wide age range (children or adults)


Presentation




• Usually occur in skin and subcutaneous tissue
• Occasionally arise in deep soft tissues (tendon, synovium, bone)

• Classified based on clinical features

image Xanthelasma

– Soft yellow plaques

– Predilection for eyelids and periorbital skin; often bilateral

image Eruptive xanthoma

– Sudden onset of small, yellow papules with erythematous halo

– Predilection for gluteal region, thigh, and shoulders

image Tuberous xanthoma

– Firm yellow subcutaneous nodules and plaques

– Predilection for elbow, knee, gluteal region, and fingers

image Tendinous xanthoma

– Soft tissue mass associated with tendons, ligaments, &/or fascia; predilection for hands, feet, and Achilles tendon

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Apr 24, 2017 | Posted by in PATHOLOGY & LABORATORY MEDICINE | Comments Off on Xanthomas
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