Cutaneous Larva Migrans
Histology: The histopathology is nonspecific unless the actual larva is biopsied. This is highly unlikely, because the larva is typically an estimated 2 to 3 cm ahead of the leading…
Coccidioidomycosis
Histology: Punch biopsy or excisional biopsy specimens show a diffuse granulomatous inflammatory infiltrate. Pseudocarcinomatous epithelial hyperplasia often overlies the granulomatous infiltrate. Within the granulomatous portion of the dermal infiltrate are…
Pemphigus Vulgaris
Pathogenesis: Pemphigus vulgaris is a chronic autoimmune blistering disease in which autoantibodies are directed against the desmosomal plaque. The desmosomal plaque is the most crucial element that holds adjacent keratinocytes…
Actinomycosis
Anaerobic culture of the purulent material or a portion of the tissue is critical for proper identification of the responsible organism and ultimately for choosing the appropriate therapy. Material should…
Paraneoplastic Pemphigus
Pathogenesis: Paraneoplastic pemphigus is caused by circulating autoantibodies directed against various intercellular keratinocyte proteins. The most commonly found antibodies are directed against the plakin family of proteins, which include envoplakin…
Dermatitis Herpetiformis
Histology: Early lesions of dermatitis herpetiformis show subepidermal clefting with a neutrophil-rich infiltrate in the papillary dermis. As the lesions progress, subepidermal blistering becomes prominent, and the papillary dermis is…
Mucous Membrane Pemphigoid
Histology: Subepidermal blistering that heals with scar formation is the hallmark of this disease. The blistering takes place just below the keratinocyte, within in the lamina lucida. Immunohistochemical staining with…
Bullous Pemphigoid
Histology: Routine hematoxylin and eosin staining reveals a cell-poor subepidermal blister with scattered eosinophils. The histological differential diagnosis can be between bullous pemphigoid and epidermolysis bullosa acquisita (EBA). Immunofluorescence staining…
Basement Membrane Zone and Hemidesmosome
The lamina lucida is so named because of its translucent appearance on electron microscopy. In comparison, the lamina densa is an electron-dense region that lies just below the lamina lucida….
