SAN DIEGO — Many times the most important feature in establishing the correct diagnosis of melanoma is evaluating the lesion's overall growth pattern, referred to as its architecture or silhouette, said Dr. David J. Barnette Jr.
"These architectural features include size, symmetry, and circumscription," Dr. Barnette, said at a melanoma update sponsored by the Scripps Clinic. "Accurate prognosis relies on assessing tumor depth, whereas making the correct diagnosis may require evaluation of the lateral aspects of the lesion."
After you perform a biopsy and send it to a pathologist, the results should fall under one of three categories: "benign"- a nevus or one of its variants; "malignant"- a melanoma; or "not sure"- either the diagnosis or biologic behavior of the lesion is unknown, said Dr. Barnette, a dermatopathologist and dermatologist at the Scripps Clinic, La Jolla, Calif. A pathology report may convey the latter diagnosis with terms such as atypical nevus, atypical melanocytic lesion, atypical melanocytosis, atypical melanocytic hyperplasia (AMH), or melanocytic tumor of uncertain malignant potential.
"These terms are not problematic if the clinician and pathologist are on the same page as to what they mean and how to best treat the patient," Dr. Barnette said, noting that he and his associates use the term AMH when the diagnosis is unclear.
"If the lesion is not completely excised, we include a recommendation for re-excision," he said. "This is appropriate treatment for either an atypical nevus or an evolving melanoma in situ. Communication between the pathologist and clinician and good clinicopathologic correlation are critical in preventing over- and under-treatment."
A biopsy report for an established diagnosis of melanoma should include a comment regarding its Breslow tumor depth, mitotic rate, presence or ulceration if applicable, and an assessment of the surgical margins, especially if an excisional biopsy was performed. Other elements to consider including in a biopsy report include site of lesion, type of biopsy, presence of angiolymphatic invasion (if present), margin status, melanoma subtype, regression (if present), and host response, including plasma cells and tumor-infiltrating lymphocytes (if present).
In November 2003, the Association of Directors of Anatomic and Surgical Pathology established a diagnostic checklist for skin melanoma.
Dr. Barnette disclosed no conflicts of interests.