BACKGROUND: Most melanomas when first diagnosed clinically are larger than common benign melanocytic nevi ( > 6 mm). Smaller melanomas, however, may occasionally occur. Yet, very little is known about them. OBJECTIVE: To determine the incidence and delineate the clinical and histologic characteristics of small-diameter invasive melanomas. METHODS: Slides of all melanomas diagnosed between 1984-1993 were reviewed and measured. All invasive lesions less than 6 mm were further scrutinized clinically and morphologically. RESULTS: Among 357 invasive melanomas, 16 (4.4%) were less than 6 mm. Most lesions lacked some of the histologic features usually seen in large melanomas. One half of them were over 0.75 mm deep. Patients with small melanomas were on average 15 years younger than those with large lesions. In females, sites on the upper extremities predominate. In females, small melanomas had clinical signs of melanoma, while in males they resembled nevi. CONCLUSION: Melanomas smaller than 6 mm are not rare. Clinicians and pathologists must learn their features in order to diagnose them properly.
BACKGROUND: Most melanomas when first diagnosed clinically are larger than common benign melanocytic nevi ( > 6 mm). Smaller melanomas, however, may occasionally occur. Yet, very little is known about them. OBJECTIVE: To determine the incidence and delineate the clinical and histologic characteristics of small-diameter invasive melanomas. METHODS: Slides of all melanomas diagnosed between 1984-1993 were reviewed and measured. All invasive lesions less than 6 mm were further scrutinized clinically and morphologically. RESULTS: Among 357 invasive melanomas, 16 (4.4%) were less than 6 mm. Most lesions lacked some of the histologic features usually seen in large melanomas. One half of them were over 0.75 mm deep. Patients with small melanomas were on average 15 years younger than those with large lesions. In females, sites on the upper extremities predominate. In females, small melanomas had clinical signs of melanoma, while in males they resembled nevi. CONCLUSION:Melanomas smaller than 6 mm are not rare. Clinicians and pathologists must learn their features in order to diagnose them properly.