Slide Review: Monsel's Solution

Monsel's solution, also known as ferric subsulfate solution, is a styptic agent used to stop bleeding after superficial skin biopsies.  It works by contracting tissue to seal injured blood vessels. Here, we see residual Monsel from a biopsy done several days before Mohs surgery.

Slide Review: Milial Cyst

A milial cyst is a small, keratin filled cyst, often found on the face. This lesion is quite common in women who apply moisturizers, and can also be a complication of facial cosmetic dermatology such as dermabrasion, chemical peels, and laser resurfacing.

The hardened keratin sounds like a grain of sand embedded in the tissue, making a scraping sound at each pass of the blade. 

In these sections, you can see the stratified layers of keratin lining the cyst. 

Slide Review: Tattoo Ink

TROUBLESHOOTING: Loose Knife Clamp Arm

Rolling the cryostat over bumpy cobblestone or tactile pavement can loosen the pins that hold the knife clamp arms. The microtome will probably look something like this:

Assuming everything was working just fine at the last job, all the parts should be rolling around somewhere at the bottom. Put the knife clamp arm back where it belongs. 

Now find the pin and insert it into the hole.

Use your heat sink to tap the pin all the way in. 

All fixed! 

The next time you need to go over bumpy pavement, ROLL THE CRYO SLOWLY. 

TROUBLESHOOTING: OCT mount falls off the disc

Sad mount misses his disc.

Sometimes, when you're making rough cuts or even just regular cuts, the OCT mount gets knocked off the disc. This can be caused by several things, the most common reason being:

-You took too much time putting the mount together.
Once you get the disc onto the cold bar, you need to apply OCT immediately, before the disc has a chance to get too cold. If you take too long, the pre-chilled disc will freeze the OCT before it has a chance to ooze into those tiny nooks, crannies, and holes.

You can preheat your discs on the hotplate to give yourself a few seconds leeway and some burned fingers.

The most reliable way to make sure your mounts stay on the disc is to touch the tip of the OCT bottle to one of the holes and give it a good squeeze to force the OCT into the hole.

In figure A, the OCT froze before getting into the holes, making it the type that's likely to fall off the disc. You want the OCT to freeze inside the holes as shown in B, C, or D.

Other reasons why your mounts are getting knocked off the discs:

-The surface of the disc needs to be roughed up. Refer to the post below. 
-There are loose screws.  Check the knife screws, blade screws, etc. Check everything!
-Your cryo has been off for several hours and is too warm to cut on.  The OCT block isn't frozen solid enough to hold on to the disc. Bend a Freeze-It straw so that you can freeze the backside of the disc as well as the front.
-Your rough cuts are too aggressive.  When you're advancing the wheel by hand (e.g. cutting through the safety layer), avoid cutting too deeply with each turn.

How to Rough Up Your Discs

Roughing up your discs provides extra grooves for the OCT to cling on to, hopefully preventing the OCT block from falling off when you're cutting sections. There are a few different types of discs that we work with:

Copper discs without holes: This type is excellent at gripping the OCT. Personally, I've never felt the need to rough these discs up, as they do a perfectly good job as they are. They DO, however, take more time to get cold.

Aluminum discs without holes: This type freezes quicker than the copper discs. The circular ridges seem to grip the OCT relatively well, but you might want to rough up the surface for added gripping power, just in case.

Aluminum discs with holes: These are the discs that give techs the most problems. I absolutely recommend roughing these up.



There are two ways to rough up a disc (plus one extra that I'll explain later but won't recommend):

Method #1 - Rub the surface of your disc against cement.  You'll probably find a suitable surface in a parking lot.

Method #2 - Use a screwdriver and your body weight.  This is my favorite method, since you can do it in the office and don't need to remember to do it on the way home. Place your disc ON A CARPETED FLOOR ONLY with your screwdriver at the center of the disc. Lean your body weight into it until the screwdriver slides down to the edge of the disc.  Turn the disc and repeat until you get several grooves radiating out from the center.

Method #3 - Garbage disposal. Obviously, I can't recommend putting your disc through a garbage disposal. I only discovered this method by accident. Ironically, it transformed a problem disc into one of the best discs I've ever worked with. Again, don't do this!

Making Slanted OCT Blocks

Why:  With some cryostats, you NEED to make slanted OCT blocks in order to line up.  (Note that I said “some.”  You never know which cryos require it.  It keeps things exciting.)

If you make a perfectly level block and try to line it up on one of said cryos, you’ll find that it's impossible to close the gap between the top of the block and the blade.  Your options at this point are:

1. Rotate the block upside down. You'll also have to pick up the sections with an upside-down slide so that piece 1 is still on the left side. Or,
2. Melt it down and remake it as a slanted block.

Since you never know which cryos require this, it’s best to just get into the habit of making slanted mounts every single time. 

How:  When sandwiching the tissue between the heat sink and the disc on the cold bar, angle the mounting slide so that the OCT block is thinner on the side closest to the cryostat wall.  It doesn’t need to be steeply slanted, just a subtle slant that you probably won’t be able to see until you take the frozen block off the cold bar.  

Be careful not to make the OCT block so thin on one side that it cuts directly into the disc.  You won’t be able to get any sections from it and you’ll have to melt it down and start over. 

Overview of Cancer Types

Basal Cell Carcinoma

Basal Cell Carcinoma (BCC) is the most common form of skin cancer, with over two million cases being diagnosed every year in the United States alone.  This type of cancer is slow growing and rarely spreads to other parts of the body.  If left untreated, however, it can cause disfigurement by invading and damaging the surrounding nerves and tissues.  Most cases of BCC are caused by cumulative UV exposure but can also occur in areas that are protected from the sun.  

Basal cells line the deepest layer of the epidermis.  They are responsible for producing new skin cells to replace the dead ones that are regularly sloughed off.  With enough UV damage, these cells produce skin cells at an abnormal, uncontrolled rate.

BCCs often look like open sores, red patches, pearly pink growths, or scars.  Since they can take on such a variety of appearances, a biopsy is the only reliable way to make a definitive diagnosis.

Nodular:  The most common type of BCC.  Usually presents as a round, pearly growth with rolled edges that may be pigmented (brown) or have small blood vessels on the surface.

Superficial: A less common form of BCC.  Looks like a crusty red patch with a threadlike waxy border.  Is often mistaken for other skin conditions such as eczema or psoriasis. 

Fibrosing or Sclerotic:  A fairly uncommon type of BCC.  Appears ivory-white, is flat or slightly depressed like a scar, and feels firm to the touch.  Difficult to excise because it is often infiltrative and has indistinct margins.   

Squamous Cell Carcinoma

Squamous cell carcinoma (SCC) is the second most common form of skin cancer (BCC > SCC > Melanoma).  An estimated 700,000 cases of SCC are diagnosed each year in the US, resulting in approximately 2,500 deaths.  Like BCC, SCC is mainly caused by cumulative UV exposure; however, it is more dangerous than BCC because it can spread to the lymph nodes or other organs, and in some cases be fatal.

Whereas basal cells are only found in the epidermis, squamous cells are found in both the epidermis and mucosal membranes.  Thus, SCCs can also occur on the genitals and inside the mouth, nostrils, and eyelids.

SCCs often look like scaly red patches, open sores, elevated growths with a central depression, or warts.  They may also crust or bleed.

SCC in situ (also known as Bowen’s disease):  An early form of cancer that has yet to penetrate the basement membrane and is still confined to site of the original cancer cell.  Often appears as a thick scaly red rash.

Well differentiated SCC:  The cancer has penetrated the basement membrane and is now spreading through the dermis and adjacent tissues.  It is now able to metastasize (spread to other organs and form secondary tumors there)  These often appear as very thick, crusty lesions with tops that may fall off but invariably grow back.

Aggressive, poorly differentiated SCC:  The most dangerous type of SCC because it grows very quickly and has a greater tendency to metastasize.  They have a wide variety of appearances (soft, hard, open sores, etc.)


Actinic keratosis:  Common sunspots, the least dangerous type of SCC (more of a pre-cancer).  The surrounding skin often looks sun damaged (blotchy, freckled, and wrinkled).

Melanoma

Melanoma is less common than other skin cancers but is by far the most dangerous if not found early, causing the majority (75%) of deaths related to skin cancer.  More than 76,000 cases of melanoma are diagnosed in the US every year.  If the cancer is found in the early stages, it can usually be removed with surgery.  If the melanoma has spread, it will need to be treated with chemo- and immunotherapy, or radiation therapy.

 

Melanomas begin in the melanocytes (pigment-producing cells) and are caused by UV damage and genetic factors.  They may appear suddenly on the skin or develop from an existing mole.  Early signs of melanoma are summarized by the mnemonic “ABCDE”:

Asymmetry

Borders (irregular edges that are notched, uneven, or blurred)

Color (different shades of brown, black, or tan)

Diameter (>6mm, the size of a pencil eraser)

Evolving over time