Pathology: Kaposi sarcoma

Kaposi sarcoma

• Multinodular; spindle cell fascicles

• Amphophilic cytoplasm with occasional hyaline globules

• Monomorphic ovoid nuclei with small nucleoli; mitotic activity

• IHC: ERG, HHV8

Kaposi sarcoma

• Spindle cell fascicles

• Amphophilic cytoplasm with occasional hyaline globules

• Monomorphic ovoid nuclei with small nucleoli; mitotic activity

• IHC: HHV8

Kaposi sarcoma

•  Spindle cell fascicles

• Amphophilic cytoplasm with occasional hyaline globules

• Monomorphic ovoid nuclei with small nucleoli; mitotic activity

• IHC: ERG, HHV8

Kaposi sarcoma

• Spindle cell fascicles-whorls

• Amphophilic cytoplasm with occasional hyaline globules

• Monomorphic ovoid nuclei with small nucleoli; mitotic activity

• Necrosis; mild chronic inflammatory infiltrate

• IHC: CD31, HHV8 (x2)* 

* NB: speckled pattern on higher magnification

Kaposi sarcoma

• Spindle cell fascicles

• Amphophilic cytoplasm with occasional hyaline globules

• Monomorphic ovoid nuclei with small nucleoli; mitotic activity

• Brisk lymphoplasmacytic inflammatory infiltrate; interstitial haemorrhage with abundant siderophages

• IHC: HHV8

Kaposi sarcoma

• Spindle cell fascicles

• Amphophilic cytoplasm with occasional hyaline globules

• Monomorphic ovoid nuclei with small nucleoli; mitotic activity

• Mild lymphoplasmacytic inflammatory infiltrate; interstitial haemorrhage with occasional  siderophages

• IHC: HHV8

Kaposi sarcoma

• Spindle cell fascicles-whorls

• Eosinophilic-amphophilic cytoplasm with occasional clear vacuoles and hyaline globules

• Monomorphic ovoid nuclei with small nucleoli; mitotic activity

• Minimal chronic inflammation

• IHC: ERG, HHV8

Kaposi sarcoma

• Nests of epithelioid cells focally lining slit-like spaces

• Amphophilic cytoplasm with occasional hyaline globules

• Hyperchromatic round-ovoid nuclei with mild atypia and prominent small nucleoli; mitotic activity

• "Crush" artifact; apoptotic debris; mild chronic inflammatory infiltrate

• IHC: ERG, HHV8