Pitfalls in dermatopathology: when things are not what they seem

By integrating the clinical features of a skin lesion and its histological findings, dermatopathologists are usually able to correctly diagnose most skin disorders. However, situations often arise where clinical appearance and impression from a superficial histopathologic examination are misleading and may direct to a completely erroneous diagnosis. These pitfalls in diagnosis are most significant when they involve various tumors with a malignant potential. In these diseases, a misdiagnosis is likely to have serious medical consequences. It is important to be aware of these specific histological mimickers, because only then may the dermatopathologist be able to detect the subtle changes that lead to a correct diagnosis. Clinical–pathological correlation is also essential. Entities that are prone to misdiagnosis can generally be divided into three categories: skin malignancies that resemble reactive conditions or benign neoplasms; benign conditions that masquerade as malignancies; and tumors that may be mi...