The key to successful embedding is differentiating the epidermis from other skin layers. The orientation of skin tissue is determined by epidermis.
10 Steps to Successful Skin Embedding
- Use communication from the grossing attendant to identify the tissue in the cassette and look for notations about inks or special embedding instructions, like alopecia skin punches.
- Choose proper mold size for the tissue size. Leave room around the edges and do not crowd tissue sections.
- Embed skin diagonally, facing such a way that the microtome blade cuts through the fat and dermis first and epidermis/hair last.
- Arrange tissue according to size in the mold, from smallest to largest, with the epidermis facing the same direction in all skin sections. Organized embedding ensures that the pathologist does not miss any skin fragments.
- Embed skins on "edge," or "cut side" down so that all layers are visible, or ink down if instructed. Nails are also embedded on edge.
- Embed small specimens that are submitted whole on edge (if shave), on side (if punch). Punch biopsies for alopecia may need to be embedded cut or inked surfaces down, with the hair follicles perpendicular to the mold base. Check laboratory protocol.
- Use a magnifying glass in order to embed tiny skin samples on edge. Skin scrapings and fragments may be difficult to arrange on edge due to the quantity and quality of the sample.
- Uncurl skin sections gently with forceps and warm them on the embedding center before embedding on edge.
- Ensure all skin sections have epidermis perpendicular to the embedding mold at all times. Skin shaves fall easily and should be straightened before paraffin hardens completely.
- Press down skin excisions so that the entire surface lays flat from edge to edge.
