Update in dermatopathology.

Inflammatory skin disease is a diagnostic challenge for both dermatologists and pathologists. Unlike the diagnosis of cutaneous neoplasms, biopsies of inflammatory disorders generally present a differential diagnosis for the pathologist. Similarly, the dermatologist is also presented with a clinical differential diagnosis prompting the biopsy. Assimilating all of the information is challenging yet rewarding when an accurate diagnosis is made. In this review we present several "newer" inflammatory diseases of the skin and discuss the differential diagnosis. Many of these entities are associated with underlying systemic disease, making early recognition and diagnosis critical. Pathologists should be familiar with these histopathologic findings to assist with the optimal clinical-pathological diagnosis.