Histopathologic Characteristics of Vitiligo-Like Macules in Scleroderma: A Case Report and Review of the Literature.

Scleroderma, or systemic sclerosis, is an autoimmune connective tissue disorder characterized by vascular dysfunction, immune dysregulation, and fibrosis. Salt-and-pepper pigmentation is a cutaneous manifestation that can mimic vitiligo and thus pose a diagnostic challenge for clinicians. We present a case of a 40-year-old woman with a known history of scleroderma presenting with hypopigmented macules on the lower extremities. Biopsy revealed absent junctional melanocytes through MART1 and SOX10 stains, diminished periadnexal and periadventitial fat in the superficial dermis, and diminished CD34-positive dermal dendrocytes in the papillary and superficial reticular dermis, which collectively supported the diagnosis of a cutaneous manifestation of scleroderma rather than vitiligo. A literature review was conducted using PubMed, Google Scholar, and Scopus and identified 5 existing reports detailing histopathologic findings of salt-and-pepper pigmentation in scleroderma. These findings were compared with histopathologic features observed in the presented case. This case report and review is the first to highlight absent or reduced melanocytes through immunohistochemistry staining and diminished CD34-positive dermal dendrocytes in histopathologic evaluation of this pigmentation pattern, alongside serologic testing of scleroderma. This methodology enhances diagnostic ability, which can aid in early recognition and significantly affect quality of life and prognosis. Further research is still needed to elucidate molecular mechanisms underlying these pigmentary changes, which may bolster early detection strategies. It may also be prudent to include scleroderma in the differential diagnosis alongside vitiligo when evaluating hypopigmented lesions.