Histologic Diagnosis of Inflammatory Skin Diseases

A systemic disease, which manifests itself in the skin first as violaceous macules and patches that tend to progress to papules and plaques, and sometimes to nodules and tumors, all of which represent hyperplasia of endothelial cells….

Histologic Diagnosis of Inflammatory Skin Diseases

Images

Images 11.16.1A: Nodular dermatosis + 11.16.1B: Proliferation of small blood vessels enclosed partially by collarettes of epithelium = Pyogenic granuloma, early ┬áNote the large, muscle-containing “feeder” vessel at the base of…

Differential Diagnosis in Dermatopathology

Discussions

…e innumerable dilated blood vessels lined by plump endothelial cells, some endothelial cells in mitosis, a mixed infiltrate of inflammatory cells, stroma that tends to be edematous and contain some mucin and large fibrocytes, a thinned epidermis with…

Differential Diagnosis in Dermatopathology

Pyogenic granuloma vs. Bacillary angiomatosis

A systemic disease, which manifests itself in the skin first as violaceous macules and patches that tend to progress to papules and plaques, and sometimes to nodules and tumors, all of which represent hyperplasia of endothelial cells….

Differential Diagnosis in Dermatopathology

Differential Diagnosis

…of collagen and no nuclear “dust” of inflammatory cells 3. Degeneration of collagen and nuclear “dust” of inflammatory cells in the center of palisades of histiocytes 4. Oval and spindle-shaped fibrocytes constitute the der…

Differential Diagnosis in Dermatopathology

Differential Diagnosis

Morphea, late stage Collagenous nevus 1. Epidermis normal or thinned with effacement of rete ridges 1. Epidermis normal or gently mammillated 2. Thick collagen bundles aligned parallel to the skin surface 2. Thick collagen bundles arranged obl…

Differential Diagnosis in Dermatopathology

Differential Diagnosis

…on, but not acanthotic at the periphery of it 3. No nests of cells in the dermis 3. Nests of cells in the dermis 4. Stellate, oval, spindle-shaped, and round cells (fibrocytes and histiocytes); no polygonal cells 4. Polygonal cells (abnormal mela…

Differential Diagnosis in Dermatopathology

Discussions

…residuum of a once dense infiltrate of lymphocytes and plasma cells may be present even at a late stage of morphea. No inflammatory cells are seen, however, in a collagenous nevus. Orientation of collagen bundles is crucial for distinguishing a late…

Differential Diagnosis in Dermatopathology

Differential Diagnosis

…and fascicles of mesenchymal cells 2. Fascicles of mesenchymal cells common, but no whorls of them 3. Nuclei of mesenchymal cells not crowded 3. Nuclei of mesenchymal cells crowded 4. Nuclei relatively monomorphic, i.e., mostly plump oval and spi…

Differential Diagnosis in Dermatopathology

Discussions

…ral findings histopathologic in common, among them mesenchymal cells with abundant pink cytoplasm scattered among bundles of collagen, multinucleate cells in sections of tissue of some specimens, deposits of mucin in company with an increased number…