Precision Pathology

July 2010 – Melanoma


An elderly patient presented with an irregular dark-pigmented lesion measuring one centimeter in diameter on the tip of the nose.









Melanoma can occur anywhere on the body and affect anyone, regardless of gender or age.

Some of the risk factors for melanoma include exposure to sunlight and family history of melanoma as well as genetic factors including light-colored skin, blue eyes and red or blond hair. Many people are successfully treated; however melanoma can come back.

Melanoma is a malignant lesion which may be located in-situ along the dermo-epidermal junction or may be invasive to the dermis. All types of melanoma almost invariably originate from melanocytes at the dermo-epidermal junction. They can also be associated with a pre-existing benign nevus. The main cause of melanoma is thought to be due to sunlight exposure; either episodic (sunburn) or chronic.

Histologically: The lesion is usually poorly circumscribed and consists of markedly atypical melanocytes arranged in nests and as individual cells along the epidermal-dermal junction. These atypical melanocytes extend upward into the epidermis and deeply into the dermis as they track along adnexal structures. The malignancy can be accompanied by a fairly dense lymphoplasmacytic inflammatory infiltrate located near the epidermal-dermal junction.

Treatment includes surgery, chemotherapy or radiation therapy. Some patients may have a combination of treatments.

Immunostains which are strongly positive in the tumor cells: S-100 and MART-1.

Hanan H. Ayoub, MD
Hanan H. Ayoub, MD