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Itchy skin disease

Dermatopathology key points test

Skin biopsies are taken for the following reasons. #! To make or confirm a clinical diagnosis #! To remove a skin lesion #! To determine whether margins of excision are adequate #! Research Explanation: Skin biopsies are taken to remove a lesion, to determine whether margins of excision are adequate, and to make or confirm a clinical diagnosis. They may also be necessary for research. Which of the following skin specimens is not used for dermatopathology? # Excision biopsy #! Skin scrapings # Punch biopsies # Curettings Explanation: Skin specimens include excision, incision, shave, punch biopsies and curettings. Skin scrapings are performed for potassium hydroxide microscopy and fungal culture. Regarding biopsy specimens: # The majority of punch biopsies use 10mm elliptical blades || Punch biopsies are most frequently 3 to 5 mm in diameter with round blade. # The specimen should be removed from fixative after 2 hours || Specimens should normally remain in fixative for at least 24 hours. # Paraffin blocks are sliced into 3-5 mm sections || Paraffin blocks are sliced into 3-5 micron sections. #! Skin specimens are usually stained using haematoxylin and eosin || Standard staining is with haematoxylin and eosin (H and E). Additional stains may be necessary when the diagnosis is unclear and to determine the nature of specific cells and structures. # Haematoxylin is acidic and stains nuclei red || Haematoxylin is alkaline and stains nuclei blue. #! Eosin is acidic and stains cell cytoplasm red # Direct immunofluorescence is used to identify tumours || Direct immunofluorescence stains immunoglobulins and is especially useful to identify immunobullous diseases. # Immunohistochemistry is used to identify tumours ||Immunohistochemistry is used to label immunoreactive materials to determine cell origin of tumours and identify certain infections.