Malignant melanoma, light micrograph. Melanoma exhibits a variety of microscopic patterns. The tumour cells can be epithelioid, spindle shaped, signet ring type, or highly anaplastic with bizarre shape. This light micrograph shows nests of epithelioid cells with abundant eosinophilic cytoplasm, large vesicular nuclei, and prominent nucleoli. There is no appreciable pigment within the tumour cells. Melanomas lacking pigment are called amelanotic melanomas. Clinically, they appear flesh-coloured or erythematous.