Retained sewing machine needle remnants as a cause of foreign body granuloma in the nail unit mimicking squamous cell carcinoma.

Abstract

showed the absence of melanocytes in the epidermis and no other changes (Fig. 2a-b). Immunohistochemistry showed negativity for Melan-A (Fig. 2c). He was diagnosed, clinically and pathologically, with vitiligo-like depigmentation induced by Xuesaitong. Published reports of drug-induced vitiligo are rare, with most reports in patients with melanoma receiving immunotherapy. It has been proposed that melanocyte antigens released by the destruction of melanoma cells after immunotherapy could trigger breakdown of the immune tolerance to normal melanocytes. Xuesaitong, a Chinese herbal medicine, mainly consists of Panax notoginseng saponins. The fact that the patient developed depigmentation within two weeks of starting the capsules with rapid spontaneous repigmentation after withdrawal supports the diagnosis of vitiligo-like depigmentation induced by Xuesaitong. It is unclear at present why this extremely rare case occurred in a 21-year-old young man. Prior studies have shown that Panax notoginseng saponins have immunological adjuvant effects on specific antibody production and cellular responses against specific antigens. It also promotes the production of IFN-c and TNF-a. Therefore, we postulate that Panax notoginseng saponins may enhance immune responses to melanocyte antigens. Furthermore, Wei et al reported that Panax notoginseng saponins led to the inhibition of proliferation in regulatory T cells. It has been suggested that decreased regulatory T cells in peripheral blood and lesional skin of patients with vitiligo could lead to weakened immunosuppressive function and, therefore, a reduced threshold for developing autoimmune disorders. However, the depigmented areas in our patient were typical for vitiligo, so the Xuesaitong may have been coincidental and not responsible for this pigmentary loss.