Wednesday, January 18, 2006

SELF TEST FOR EYE SPECIMEN GROSS EXAMINATION

Self Test
The purpose of this examination is to confront you with common problems that occur in the activities of processing specimens. Please use the procedure manual to find the answers to the questions.

Part I: Tissue Processing:

1. What are the purposes of inking a specimen in the laboratory?

2. An eyelid specimen was received without history. It was grossed in by the Ophthalmology resident who accessioned it, measured it and described it as an elliptical fragment with a nodule in the center. Without further ado he sent it for processing in a green cassette. The case settled out of court for an undisclosed sum. What was the nature of the lawsuit? If you were a lawyer for the plaintiff, what mistakes would you expose in this case?

3. Describe the steps involved in processing tissue for routine sectioning. Assume tissue is in a cassette in formalin. How does it get to the slide ? Describe all the steps including a brief description of all the solutions it must traverse.

4. Describe the difference between processing techniques for a cytospin and a cell block for cytology specimens.

5. On the cytospin requisition there is a box for unstained fixed slides. Give 3 possible uses for this unstained material other than histochemical stains.

6. Which of the following is the best preservative to prepare material when you are in doubt of the diagnosis and uncertain what tests you should get on a fragment of tissue?
a. 10% formalin
b .4% paraformaldehyde
c. 2% paraformaldehyde; 2% glutaraldehyde
d. rapid freezing in liquid nitrogen

7. Name the fixative that you would use for:
(a). a specimen for electron microscopy(b). routine paraffin embedding
(c). gene rearrangement work up(d). a conjunctiva specimen for bullous pemphigoid
(e). immunohistochemistry
8. Imagine you are a technician receiving a specimen at 5:30 AM from the technicon in paraffin for embedding. Each edge of the specimen is marked with a different color: yellow, green, orange, black, and blue. By convention, which edge will you put down in the very bottom of the metal mold unless otherwise instructed? Which dye was used to mark that edge?


Part II Specific Tissues
9. Conjunctiva Imagine yourself in your third year of residency preparing to remove a 4 mm pigmented lesion from the conjunctiva. Describe how you will prepare the tissue to send to pathology. How wide should your surgical margins be?

10. Conjunctiva The specimen is received as described above. How will you gross it in? Describe the way you will cut it, embed it, and what type of sectioning you will order from the technologist? Draw a diagram and show where you would make your cut. Show with arrows which edge or face it would be embedded on?

11. PKP Describe the steps for processing a penetrating keratoplasty specimen removed for aphakic bullous keratopathy (gross considerations and special fluids in processing).

12. Unknown corneal disease. Describe for a new disease, a suspected stromal dystrophy. It has never been described. What is the best way to maximize the information for processing? What is the most versatile choice for fixative?

13. A small corneal biopsy Dr. Cornea wants to do a corneal biopsy on an AIDS patient with a corneal ulcer. The clinical laboratory has reported S. epidermis on a scraping, but this ulcer has been progressively worsening for 2 months despite therapy. Dr. Cornea wants an answer in the shortest time because the patient is losing vision.
(a) What is the shortest turnaround time offered for a biopsy of this kind?
(b) What special stains are appropriate and when should you order them (at the time of sectioning or after seeing the H&E).
(c) The specimen is only .3mm in diameter, What can you do to make sure that the biopsy specimen will not be lost in processing.
(d) What type of sectioning will you order? (i.e deep cuts, step sections, etc....???)

14. Temporal Artery You received a 40mm segment of temporal artery. Describe how you will gross this in.
(a) What thickness will your slices of artery will you plan for the technician?
(b) Will you instruct the technician to slice along the long axis of the vessel or in cross section?
(c) How will you instruct the histology technologist to embed the specimen?(d) How many sections will you order initially? What will your instructions be to the histotechnologist?
(e) In the classic paper(s) on temporal arteritis, how big is a skip lesion? Give your answer in microns.

15. Eyelid A pentagonal resection of the eyelid is removed for a basal cell carcinoma at the medial canthus.
(a) Draw a theoretical diagram of what this might look like. On the diagram indicate how you will mark and cut the specimen.
(b) Indicate the plane of section of the tissue to obtain adequate margins.

16. Retina Dr. Retina is doing a retinal biopsy for a suspected acute retinal necrosis syndrome.
(a) What are the possible viruses ?
(b) List the ways commercially available to detect these viruses.
(c) What will you recommend to Dr. Retina for fixation and Laboratory tests?

17. Vitreous Washing The retina service sent you a cytospin specimen from a vitrectomy on a patient with AIDS. You examine the bottle record the volume, and order 1 pap stain cytospin slide and take it to the pathology lab.
(a) What diagnoses will you miss?
(b) What errors in judgment were made?
18. Foreign bodies You collect a specimen from the operating room that is labeled foreign body. It was removed during vitrectomy surgery. What is the appropriate procedure for handling, processing and storing this specimen.

19. Retinoblastoma The oncology service is going to send you an eye with a mass suspected of being a retinoblastoma. There is a family history of retinoblastoma. They want to know how to fix the eye before they send it to you. By the way they will want "genetic studies". The attending pathologist is ill. What will you recommend?
20. Lymphoma work up As a private practitioner you have a patient with suspected orbital lymphoma. You have decided to do an orbital biopsy in the operating room. When the specimen is removed, the nurse asks you what tests do you want? Your reply is "send it to pathology for a lymphoma workup". What specific things will be done in pathology as part of that work up? What is the best way to send the specimen (i.e. fixative, preservative etc.)
21. Blepharoplasty Describe the usual method in which we process blepharoblasty specimens? What are the exceptions to this method?

22. Autopsy eyes Describe how you would cut the autopsy eyes with the following features:
(a) a nevus in the periphery a 5’oclock.
(b) a surgically aphakic eye.
(c) a pseudophakic eye.
(d) an eye of a 9 month old baby.

23. The most common mistake.... You are cutting autopsy eyes in the standard fashion and the razor blade easily passes through the sclera above the optic nerve all the way to the lens. As you turn the knife to cut anteriorly, you hear a resounding “crunch”. Describe the gross features of the eye that if recognized would have allowed you to avoid this mistake?

24. What is the length of optic nerve that is to be left after preparing an autopsy eye?

25. When are residual optic nerve sections discarded?

26. How do you process epiretinal specimens?

27. What are the types of embedding bags? Which one do you use for very small specimens such as Descemet's membrane removal?

28. A Descemetectomy is performed and the specimen placed in an embedding bag. The histology lab staff report the bag is empty. The resident and the attending pathologist go over and examine the bag. There is indeed no specimen in the bag. From a quick observation of the bag the attending immediately and correctly deduces that the resident is the culprit. What mistake did the attending correctly predict was made in processing by the resident?

29. In the case above, where would you now look for the specimen? What special procedures are required on a daily basis by the residents to avoid lost specimens that slip out of cassettes?




0 Comments:

Post a Comment

Links to this post:

Create a Link

<< Home