A 74-year-old White male presented with a 1-year history of depigmented patches on the hands, arms, and face, as well as white eyelashes and eyebrows

This patient showed no evidence of recurrence in the scar where the melanoma was excised, and had no enlarged lymph nodes on palpation. His complete blood count and liver function tests were normal. A positron emission tomography (PET) scan was ordered by Dr. Nasser that revealed hypermetabolic right paratracheal, right hilar, and subcarinal lymph nodes, highly suspicious for malignant lymph nodes. The patient was referred to oncology for metastatic melanoma treatment and has been doing well on ipilimumab and nivolumab.

^{Courtesy Lucas Shapiro and Dr. Natalie Y. Nasser}

Vitiligo is an autoimmune condition characterized by the progressive destruction of melanocytes resulting in hypopigmentation or depigmentation of the skin. Vitiligo has been associated with cutaneous melanoma. Patients with melanoma can present with hypopigmentation around the primary lesion and/or bilateral symmetrical lesions similar to vitiligo. Melanoma-associated leukoderma occurs in a portion of patients with melanoma and is correlated with a favorable prognosis. Additionally, leukoderma has been described as a side effect of melanoma treatment itself. However, cases such as this one have also been reported of vitiligo-like depigmentation presenting prior to the diagnosis of metastatic melanoma.

Melanoma, like vitiligo, is considered highly immunogenic, and cytotoxic T lymphocytes (CTLs) can recognize antigens in melanoma. Furthermore, studies have shown a vitiligo-like halo around melanoma tumors, likely caused by T-cell recruitment, and this may lead to tumor destruction, but rarely total clearance. It seems that the CTL infiltrate in both diseases is similar, but regulatory T cells are decreased in vitiligo, whereas they are present in melanomas and may contribute to the immunosuppressive tumor microenvironment found at the margin of these lesions.

Leukoderma is also associated with melanoma immunotherapy which may be described as drug-induced leukoderma. Additionally, the frequency of recognition of melanoma cells by CTLs leading to hypopigmentation appears to be higher in those with metastatic disease. High immune infiltrate with CTLs and interferon-gamma (IFN-gamma) expression by type 1 T helper cells is associated with favorable prognosis. Immunotherapy with checkpoint inhibitors has shown promise in treatment augmentation for melanoma, but not all patients fully respond to therapy. Nonetheless, development of leukoderma with these treatments has been significantly associated with good therapeutic response. Depigmentation of hair and retinal epithelium has also been reported. However, drug-induced leukoderma and vitiligo seem to have clinical and biological differences, including family history of disease and serum chemokine levels. Vaccines are in production to aid in the treatment of melanoma, but researchers must first identify the appropriate antigen(s) to include.

Dr. Donna Bilu Martin

Conversely, vitiligo-like depigmentation has been reported as a harbinger of metastatic melanoma. Patients with previous excision of primary melanoma have presented months or years later with depigmentation and, upon further evaluation, have been diagnosed with metastatic melanoma. The prevalence of depigmentation in melanoma patients is about 3%-6%, and is estimated to be 7-10 times more common in those with melanoma than in the general population. In most cases, hypopigmentation follows the diagnosis of melanoma, with an average of 4.8 years after the initial diagnosis and 1-2 years after lymph node or distant metastases. It is unclear whether hypopigmentation occurs before or after the growth of metastatic lesions, but this clinical finding in a patient with previous melanoma may serve as an important clue to conduct further investigation for metastasis.

This case and the photos were submitted by Lucas Shapiro, BS, of Nova Southeastern University College of Osteopathic Medicine, Fort Lauderdale, Florida, and Natalie Y. Nasser, MD, Kaiser Permanente Riverside Medical Center; Riverside, California. The column was edited by Donna Bilu Martin, MD.

Dr. Bilu Martin is a board-certified dermatologist in private practice at Premier Dermatology, MD, in Aventura, Florida More diagnostic cases are available at mdedge.com/dermatology. To submit a case for possible publication, send an email to dermnews@mdedge.com.

References

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Cho EA et al. Ann Dermatol. 2009 May;21(2):178-181.

Failla CM et al. Int J Mol Sci. 2019 Nov 15;20(22):5731.