Pitfalls in the diagnosis of melanocytic tumours: is immunohistochemistry helpful?

The diagnosis and differential diagnosis of benign, intermediate and malignant melanocytic neoplasms remain a recurring and clinically important challenge in dermatopathology. The difficulty is not limited to rare melanoma variants, it also includes non-melanocytic lesions that simulate melanocytic tumours, benign melanocytic proliferations with worrisome architectural or cytological features, and malignant melanomas with deceptively bland morphology. In such settings, immunohistochemistry is not a substitute for careful histopathological assessment, but it may provide decisive ancillary information when applied as a targeted panel and interpreted in the appropriate morphological and clinical context. This review summarises selected diagnostic pitfalls in melanocytic pathology and highlights the contribution, limitations and practical value of established and newer immunohistochemical markers.