Panniculitis

Abstract

The panniculitides are a heterogenous group of inflammatory disorders involving the subcutaneous adipose tissue. Diagnosis remains a challenge to clinicians and pathologists alike for several reasons. First, clinical monotony is common among the diseases. Second, there are often sampling issues, including inadequate superficial biopsies, which preclude optimal evaluation of the fat. Finally, as in all cutaneous inflammatory diseases, the panniculitides are dynamic processes that may demonstrate different histologic features at different stages of development. For example, early lesions of erythema nodosum are characterized by neutrophils permeating the connective tissue septa; in contrast, late stage lesions demonstrate granulomatous inflammation with prominent septal fibrosis.