The role of the pathologist in the diagnosis of melanoma.

The pathologist plays a vital role in patients with malignant melanoma. Dermatologists, surgeons, and oncologists must rely on the pathologist for accurate and complete diagnoses. Although most melanomas can be easily recognized with routine histopathology, special stains, including immunohistochemistry, may be necessary to differentiate melanoma from other cutaneous malignancies. Likewise, there are benign entities that can mimic melanoma microscopically, including Spitz nevi, pigmented spindle cell nevi, deep-penetrating nevi, and Monsel's reaction. Recognition of these entities is important to avoid unnecessary surgery, testing, adjuvant therapy, and unnecessary concern by the patients and their families. In addition to making an accurate diagnosis, the pathologist should report prognostic histologic attributes that may influence therapy and follow-up care for these patients. These histologic features should be recorded in the pathology report. This chapter provides a brief review of the most important histologic attributes that should be identified and reported by the pathologist.