Skin – Benign nevus showing weak Melanoma gp100 immunostaining in the superficial tumor layers while Melanoma gp100 staining is lost in more mature cells of deeper tumor cell nests. Note: Strong Melanoma gp100 positivity of melanocytes in the normal skin.

Skin – Malignant melanoma showing moderate to strong Melanoma gp100 immunostaining in a fraction of tumor cells.

Skin – Malignant melanoma showing strong Melanoma gp100 immunostaining in all tumor cells.

Skin – Malignant melanoma showing strong Melanoma gp100 immunostaining in virtually all tumor cells.

Skin – Malignant melanoma showing weak to moderate Melanoma gp100 immunostaining in few tumor cells.

Skin – Melanoma gp100 negative basal cell carcinoma containing few (non-neoplastic) Melanoma gp100 positive melanocytes.

Skin – Melanoma gp100 negative basal cell carcinoma containing numerous Melanoma gp100 positive (non-neoplastic) melanocytes.

Skin – Melanoma gp100 negative basal cell carcinoma.

Skin – Melanoma gp100 negative benign nevus.

Skin – Melanoma gp100 negative benign nevus. Note- Strong Melanoma gp100 positivity of melanocytes in the normal skin.

Skin – Melanoma gp100 negative malignant melanoma.

Skin – Melanoma gp100 negative squamous cell carcinoma.

Thyroid – Melanoma gp100 negative adenoma.

Thyroid – Melanoma gp100 negative anaplastic carcinoma.

Thyroid – Melanoma gp100 negative follicular carcinoma.

Thyroid – Melanoma gp100 negative medullary carcinoma.

Thyroid- Melanoma gp100 negative papillary carcinoma.