Sentinel node and Potpourri of answers

From:Jeff Silverman

Carol- Clean basemolds by boiling on a hot plate in a tub of soapy water.
Turn off the heat and all the paraffin will solidify on top. Rinse and dry.
That's how we used to clean our round metal  tissue cassettes and screens in
the 70's before I switched to plastic cassettes. Heck, now we even use
plastic base molds :-) Really, you shouldn't have to clean them but once a
month. And that mold release spray, that makes me choke if I even go near
where it was sprayed. That and the DMSO in Paraplast Plus are the two
chemicals that make Me sick in histology.

Lynn- You are wasting valuable dehydration space with three formalin
stations. You only need one long fixation bath, just change the fixative
every day or every other day if light. Try this:

Switch to one formalin for three to five hours (we use five hours).
70% alcohol- 40 minutes
100% 40 minutes (this bath will become 95% the first time you use it.)
100% 40 minutes
100% 40 minutes
100% 40 minutes
100% 40 minutes
100% 40 minutes
Xylene 1 hour
Xylene 1 hour
Wax 40 minutes
Wax 40 minutes
Wax 40 minutes
Wax 40 minutes

Works very well for us using Histochoice fixative, pure ethanol from
pharmacy, xylene, and plain Paraplast, which same we use also to embed in.
Hope this helps.

Lynn McKee- All that mumbo jumbo is for clinical lab tests. The CAP has a
separate checklist for IHC. Basically- they want you to check buffer pH's,
document validation for all new lots of antibodies and detection reagents
against the old ones using control slides, validation of control blocks,
specific criteria for controls for each antibody. I made up a chart for
antibody validation and control block validation where we record lot numbers
(block numbers) and date validated.

Chatter in GI biopsies ( and any other cellular tissue like lymph node or
tonsil)  can be avoided by attention to three things- smooth the block face
with thin slices aftr facing to section past microchunks" that are torn out
of the block face during facing, turn the wheel as slowly and evenly  as
possible when sectioning, and get down close and apply hot breath to the
block face  like you are trying to fog up the mirror. Section at three
microns if possible.

Geoff- Vimentin is very sensitive to formalin fixation and requires HIER for
best results if your mouse tissues have been sitting in formalin for more
than 48 hours. Clone V9 is the most popular. Watch out for mouse on mouse
staining, use the right detection kit.

Jane and Karla- It seems I post this sentinel node procedure once a week but
here it is::
Microtomy wise:
Sentinel nodes for breast cancer or other carcinoma- for each block: three H
and E levels on regular slides AND  two sections on PLUS slides, one for
positive stain and one for negative control AE1/AE3 Cytokeratin

Sentinel nodes for melanoma- for each block: 3 H and E levels on regular
slides AND  three unstained slides for immunohistochemistry picked up on
PLUS slides: one each  for S-100 and HMB-45 stains, and one for the negative
control. Cut one more if you want to use MART-1, a newer  very useful marker
for melanoma as well, we don't do it.

Safety wise-

Lab Section:  Histopathology
Subject: Radiation Safety
Procedure: Sentinel Node and other Radioguided surgical specimens

PRINCIPLE: The sentinel node biopsy procedure is currently being evaluated
for its utility in sparing patients more mutilating lymphadenectomy surgery
utilizing radioactive labeling to guide sampling of the primary lymph node
drainage areas of primary breast carcinomas and malignant melanomas. This is
done by injecting a chromogenic radionuclide into the primary tumor site and
measuring the lymphatic drainage area with imaging procedures designed to
locate the first lymph node draining the area. These specimens may pose a
risk to Operating Room and Laboratory personnel due to their radioactivity.
Though the level is low, unnecessary exposure is to be avoided.

SPECIMEN: Surgically excised mammary tissue or somatic skin and soft tissue.
Surgically excised lymph nodes.

	Patient Preparation: Patient is injected in Nuclear Medicine or in the
operating room 2 hours before surgery.

1.	Upon excision, specimens are placed in labeled containers and fixed by
immersion in Histochoice Fixative.  OR personnel will label specimens as
2.	Nuclear medicine technologist must be called immediately by OR personnel.
The Nuclear Medicine technologist shall survey the specimens with a Geiger
counter. Any item reading greater than 0.2 mR/hour shall be taken by Nuclear
Medicine technologist to that departmentís secure area and allowed to decay
for 60 hours (10 half lives) and until they read less than 0.2mR/hour.
a.	Operating room work areas and refuse reading more than 0.2 mr/hour are
decontaminated or removed to Nuclear Medicine for decay if readings exceed
3.	The specimen will be logged in Nuclear Medicine. The specimen is brought
to pathology by Nuclear Medicine after decay has been accomplished. The
specimen is then signed for by Pathology.
4.	Intraoperative examination of radioactive specimens is discouraged. If
this is necessary, use remote handling techniques and call  Nuclear Medicine
to test the specimen and advise Pathology as to the level of radiation.
5.	Examine in a plastic tray to contain all spillage. After completion of
the examination, all work surfaces and absorbent materials are to be tested
by Nuclear Medicine in the Pathology Department.  If readings are greater
than 0.2mR/hour,  all refuse is red bagged and taken to Nuclear Medicine to
decay for 10 half lives (60 hours).  The grossing work area is tested and if
necessary decontaminated according to Nuclear Medicine protocols. The
specimen is taken to Nuclear Medicine for decay, logged in, and returned to
Pathology as above.

REFERENCES:  Radiation Safety Officer

  ANNUAL REVIEW:     DATE: ___/___/02  ___/___/03___/___04 ___/___05

               REVIEWED BY:  __________   __________     __________
___________  _________

Placentas- I must gross practically unfixed placentas all the time. You must
use a new sharp scalpel blade and slice gently. Still, when I take a slice
and it is too thick, I lay it flat on the grossing board and place my
scissors flat against the soft chorionic tissue, press gently and snip off
what protrudes. In this way I can usually make it nice and thin (4MM).
Rinsing the blood out of your section with water also helps with processing.
If the chorionic plate is too thick, you must use two cassettes.


Jeff Silverman HT HTL QIHC (ASCP)
Suthside Hospital
Bay Shore NY USA

<< Previous Message | Next Message >>