Consider melanoma-associated leukoderma (MAL) as a possible diagnosis in patients presenting with atypical vitiligo-like skin depigmentation that is refractory to standard treatment, advised the authors of a series of seven such cases.
In a research letter published online in the British Journal of Dermatology, Dr. H.E. Teulings and colleagues from the department of dermatology and the Netherlands Institute for Pigment Disorders at the University of Amsterdam, presented a retrospective analysis of seven patients diagnosed with MAL from 2009-2014, who had been initially diagnosed with nonsegmental vitiligo.
The authors defined MAL as “depigmentation that developed within 1 year before the detection of a primary melanoma or within 3 years before the detection of melanoma metastases with an unknown primary tumour.”
The five women and two men were white and were older (aged 45 to 72 years). They had experienced a sudden onset of highly progressive hypo- and depigmentation, which the authors described as often consisting of “round, patchy, confetti-like lesions” measuring 4-5 mm in diameter; most were scattered symmetrically over the trunk, extremities, and/or face (Br J Dermatol. 2016 Jun 7. doi: 10.1111/bjd.14790).
The authors noted that this presentation was unlike typical vitiligo, “which is often bilaterally distributed in an acrofacial pattern, or scattered symmetrically over the entire body with a predilection for extensor surfaces with a relatively early onset in life and a slowly evolving disease course over time.”
The lesions were also generally resistant to topical steroids and UV phototherapy, and six of the seven patients had no family history of vitiligo. The patients were either diagnosed with a primary melanoma at first presentation or were later diagnosed with metastatic melanoma. The majority responded well to immunotherapy, although one patient died.
“In conclusion, although MAL only constitutes a small percentage of patients presenting with vitiligo-like depigmentation, awareness of this phenomenon and correct diagnosis of these patients is crucial to limit further melanoma treatment delay,” the authors wrote. “Many dermatologists are not aware of the diagnosis MAL and may easily diagnose and treat these patients as having nonsegmental vitiligo, thereby overlooking the underlying (metastatic) melanoma,” they added.
Dr. Teulings is supported by a grant from the Dutch Cancer Society. The authors had no conflicts of interest to declare.