Nodular melanoma – low magnification
LEGEND
Nodular melanoma exhibits vertical growth, which is why it is often diagnosed at a more advanced stage than other melanoma subtypes (higher Breslow index). An intraepidermal component may sometimes be observed simultaneously.
The Breslow index is the most important prognostic factor in melanoma. It refers to the distance between the granular layer and the deepest tumor cell in the dermis.
A reactive infiltrate of inflammatory cells may sometimes be seen at the periphery.
Dermal nodular infiltrate of atypical melanocytes
Occasional ulceration is seen in melanomas, especially in nodular types. This is a poor prognostic sign.
Nodular melanoma – high magnification
LEGEND
Mitoses are not always present in melanomas, but their presence is a sign of malignancy, especially when they are located in the dermis.
Vascular, lymphatic, perineural invasion, or the presence of microsatellites may occasionally be observed, all of which negatively impact the patient’s prognosis.
- Presence of multiple mitoses. Atypical mitoses may sometimes be observed (asymmetrical, tripolar, etc.)
Marked pleomorphism with highly atypical melanocytes. They vary in size and shape: some are medium-sized and round, while others are large or spindle-shaped.
