Clinicopathologic, misdiagnosis and survival differences between clinically amelanotic melanomas and pigmented melanomas

Publication date: Available online 14 January 2019

Source: Journal of the American Academy of Dermatology

Author(s): Lauren C. Strazzulla, Xiaoxue Li, Kathleen Zhu, Jean-Phillip Okhovat, Sandra J. Lee, Caroline C. Kim

Abstract

Background

Amelanotic malignant melanoma (AMM) is challenging to diagnose. Clinical risk factors for AMM are not well defined.

Objective

To investigate clinicopathologic, misdiagnosis and survival differences between AMM versus (vs.) pigmented malignant melanoma (PMM) patients.

Methods

A cross-sectional retrospective medical record review at a tertiary academic medical center.

Results

933 melanoma patients with known presenting tumor color were identified (342 AMM vs. 591 PMM). AMM was associated with older age, history of non-melanoma skin cancer and red hair, while AMM was inversely associated with a family history of melanoma, >50 nevi and a history of dysplastic nevi. AMM was more likely on the head/neck compared to PMM, had more aggressive pathologic features (greater Breslow depth/mitoses, ulceration, nodular subtype), and was less likely associated with a precursor nevus or regression. Finally, patients with AMM were more likely to be misdiagnosed than PMM (25% vs. 12% clinically; 12% vs. 7% pathologically), and had poorer melanoma-specific survival (5-year overall survival rate: 0.77 [95% confidence interval (CI): 0.72-0.82] vs. 0.84 [CI: 0.80-0.87]).

Limitations

Retrospective study design, single institutional study.

Conclusion

Greater clinician awareness, lower biopsy thresholds, and increased patient education may be useful to enhance AMM detection in patients with certain characteristics.

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