Nodular melanoma, light micrograph. Nodular melanoma (NM) accounts for 3-4% of all melanoma cases. It occurs in a relatively younger age group (5th or 6th decades) than other melanoma subtypes and is of shorter duration. It appears as a smooth firm elevated nodule or a polypoid mass covered by epidermis. The colour ranges from tan (amelanotic variants), brown, blue to black. NM are sharply circumscribed and show a vertical (invasive) growth pattern (as seen here). The epidermal component does not extend laterally in relationship to the dermal component creating a well-defined nodule.