23 NCCN Guidelines for Patients ® : Melanoma, 2018 2 Tests for melanoma Tumor tissue tests Pathology results Diagnosis. Whether melanoma is present and if so, the subtype, for example, superficial spreading melanoma. Breslow thickness. How deep the tumor has grown into the skin, measured in millimeters. Ulceration status. Whether or not the tumor’s top skin layer is present and intact (not ulcerated) or is broken or missing (ulcerated). Dermal mitotic rate. A measure of how many melanoma cells are actually growing and dividing. Peripheral margin status. Presence or absence of cancer cells in the normal- looking tissue around the sides of a tumor removed during initial biopsy or subsequent surgery. Deep margin status. Presence or absence of cancer cells in the normal- looking tissue under a tumor removed during initial biopsy or subsequent surgery. Microsatellitosis. Tiny tumors (satellites) that have spread to skin near the first melanoma tumor and can only be seen with a microscope. Tumor location. The area of the body where the tumor is found. Tumor regression. The presence of white blood cells called lymphocytes and scar-like changes that suggest a person’s immune system is attacking the skin melanoma. Tumor-infiltrating lymphocytes. Presence or absence of white blood cells that may be present in primary melanomas. Vertical growth phase. Direction of tumor growth is down into the skin. Angiolymphatic invasion. Melanoma has grown into (invaded) lymph vessels or blood vessels. Neurotropism. Melanoma cells are evident in or around nerves in the skin. Histologic subtype. Classification based on microscopic features of the melanoma.