Review Question - QID 101307

The patient’s lesion conforms to the typical presentation of malignant melanoma. Malignant melanomas typically present with asymmetry, border irregularities, color variation, and a diameter greater than 6 mm. However, there are exceptions to this rule.

Malignant melanomas commonly have two growth phases. In the first (or radial) growth phase, the lesion spreads laterally within the epidermis and is not at high risk for metastasis. In the second (or vertical) growth phase, the lesion travels downward into and even beyond the dermis and becomes invasive. Depth of invasion is the most predictive factor for the risk of metastasis and overall prognosis. Breslow's depth and Clark's level are two scales used to describe vertical invasion. Breslow's depth describes the actual depth of invasion, whereas Clark's level refers to the level of anatomical invasion.

Ebell reviews the clinical diagnosis of melanoma. The clinical diagnosis of melanoma relies on the ABCD criteria: Asymmetry in two or more axes, irregular Borders, two or more Colors, and Diameter greater than 6mm.

Payette et al. review prognostic factors in melanoma. They found that tumor thickness and depth of invasion remain the most dominant predictors of melanoma sentinal lymph node metastasis.

Illustration A depicts Breslow's depth and Clark's level for melanoma prognosis.

Incorrect answers:
Answer 1: Palisading nuclei are a common feature of basal cell carcinomas, which rarely metastasize.
Answer 2: Keratin pearls are found in squamous cell carcinomas, which rarely metastasize.
Answer 4: Though cellular atypia is commonly found in the vertical growth phase of malignant melanoma, it is less strongly associated with the risk of metastasis than the Breslow thickness.
Answer 5: Increased production of melanosomes is not known to be associated with risk of metastasis in malignant melanoma.