Clinicopathological features of hypopigmentary skin lesions and role of Melan A an immunohistochemistry marker: A cross-sectional study

Background: Hypopigmentary skin lesions comprise a diverse group of dermatological disorders resulting from alterations in melanocyte number, melanin synthesis, or melanin transfer. Because many of these conditions exhibit overlapping clinical features, accurate diagnosis often requires histopathological examination and ancillary immunohistochemical techniques. Melan-A immunohistochemistry has emerged as a valuable tool for evaluating melanocyte density and differentiating melanocytopenic from melanopenic disorders.
Aim: To study the clinicopathological spectrum of hypopigmentary skin lesions and evaluate the role of Melan-A immunohistochemistry in their subclassification. Melan-A immunohistochemistry in their subclassification.
Methodology: This cross-sectional study was conducted on 60 clinically diagnosed cases of hypopigmentary skin lesions. Detailed clinical evaluation was followed by skin biopsy and histopathological examination using routine hematoxylin and eosin staining. Clinicopathological correlation was performed in all cases. Melan-A immunohistochemistry was applied to assess melanocyte density and classify lesions into melanocytopenic and melanopenic categories. Data were analyzed using descriptive statistical methods.
Results: Among the 60 patients studied, females constituted 60% and males 40% of the study population. The majority of patients belonged to the 21–30-year age group (43%). Extremities were the most commonly involved site (55%), followed by the face (17%). Hansen’s disease was the most frequent clinical diagnosis, accounting for 26 cases (44%), and remained the most common histopathological diagnosis with 25 cases (42%). Pityriasis lichenoides chronica constituted 8 cases (14%), while post-inflammatory hypopigmentation accounted for 6 cases (10%) on histopathological examination. Histopathological analysis demonstrated characteristic findings including granuloma formation in Hansen’s disease, basal cell vacuolar degeneration in pityriasis lichenoides chronica and lichen sclerosus et atrophicus, pigment incontinence in pityriasis lichenoides chronica and post-inflammatory hypopigmentation, and reduced melanin pigment in the majority of lesions. Clinicopathological correlation showed excellent agreement, with only three discordant cases identified. Melan-A immunohistochemistry demonstrated melanocytopenia in 6 cases (10%), comprising idiopathic guttate hypomelanosis, vitiligo, and one case of pityriasis lichenoides chronica, whereas 54 cases (90%) were classified as melanopenic lesions with preserved melanocyte populations.
Conclusion: Histopathological examination remains the cornerstone for definitive diagnosis of hypopigmentary skin lesions. Melan-A immunohistochemistry serves as a valuable adjunct in differentiating melanocytopenic from melanopenic disorders, improving diagnostic accuracy and strengthening clinicopathological correlation.