Pathology: malignant melanotic nerve sheath tumour

Lobulated; spindle-epithelioid cells in short fascicles

Eosinophilic cytoplasm, with focal pigmentation

Plump ovoid nuclei, with mild pleomorphism and occasional pseudonuclear inclusions; inconspicuous mitotic activity

Prominent psammomatous calcification

IHC: CD34, S100, SOX10

Lobulated; spindle-epithelioid cells in short fascicles

Eosinophilic cytoplasm with obscuring pigmentation

Plump ovoid nuclei, with mild pleomorphism and macronucleoli; inconspicuous mitotic activity

Rare psammomatous calcification

IHC: S100, HMB45, Melan-A