Dermatopathology Case Challenge: Recognizing Mimics and Masqueraders

In a presentation by Dr. Kevin Gaddis, associate professor of dermatology at the University of Minnesota, several dermatopathology cases were discussed that challenge typical diagnostic conventions. One notable case involved a scalp lesion in a 10-year-old girl that presented a differential diagnosis dilemma, initially suggesting a cyst yet revealing a more complex infiltrative neoplasm with ductal differentiation upon closer examination. Dr. Gaddis highlighted the possibility of rare pediatric tumors, sparking a discussion on the reliability of peripheral myoepithelial layers in diagnosing adnexal neoplasms. Another case featured a middle-aged man with persistent nasal lesions, initially misdiagnosed as seborrheic dermatitis; however, subsequent biopsies identified features consistent with pemphigus foliaceous, localized to the nasal area, which illuminated the fact that such cases can exist in isolation without detectable serological markers. The third case examined a Senegalese woman with a hyperpigmented plaque leading to a diagnosis of hypertrophic lichen planus, known for its distinctive 'igneous rock' appearance, revealing nuances of endemic conditions in different geographical contexts. Each case emphasized the importance of considering a broad differential and the potential for atypical presentations in dermatopathology.