What are the key histopathological features to look for in a biopsy of suspected melanoma?

Key histopathological features to look for in a biopsy of a suspected melanoma include:

• Assessment of Breslow thickness, which measures the depth of tumour invasion and is critical for staging and management decisions.
• Presence or absence of ulceration, which is an important prognostic factor.
• Mitotic index, indicating the number of mitoses per square millimeter, with higher mitotic rates associated with more aggressive disease.
• Evaluation for lymphovascular invasion, which may suggest a higher risk of metastasis.
• Histological subtype and cellular morphology, including features such as atypical melanocytes and pagetoid spread.
• Margins of excision to ensure complete removal of the lesion.
• For certain lesions, genetic testing such as BRAF mutation analysis may be performed on the tissue sample to guide targeted therapy, especially in stage IIB and above.

These features guide staging, prognosis, and treatment planning in melanoma management ¹.