Histopathology In Practice - Sample Reception, Dissection, Processing, Embedding.
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The document outlines the processes and best practices in histopathology, including specimen reception, dissection, processing, and embedding. It emphasizes the importance of accurate documentation, dissection techniques, and embedding protocols to ensure high-quality histological samples. Additionally, it provides guidelines for categorizing specimens and details the tools and methods involved in specimen handling and processing.
Histopathology In Practice - Sample Reception, Dissection, Processing, Embedding.
- 1. Histopathology in Practice Sample Reception, Dissection, Processing, Embedding. Della Thomas Senior Biomedical Scientist Independent Histopathology Services della.thomas@unilabs.com
- 2. Histology The science concerned with the microscopic structure of tissues and organs in relation to their function. Also called microanatomy.
- 5. Specimen QC Mickey Mouse Rt nasal polyp DOB: MOUSE Mr. MICKEY 18/11/28 26/11/13 Dr. Makewell Rt nasal polyp C/O loss of function - ↓ ability to sniff out cheese O/E: nasal polyp ? nature. 18/11/28 123456 Dr. Makewell 26/11/13 8am M
- 7. Sample documenting Assign the specimen to a pathologist MOUSE Mr. MICKEY Rt nasal polyp C/O loss of function - ↓ ability to sniff out cheese O/E: nasal polyp ? nature. 18/11/28 123456 Dr. Makewell 26/11/13 8am M
- 8. Cassetting
- 9. Specimen Dissection - the stage
- 10. Dissecting props • • • • • • • • • Cutting board Forceps Ruler Scalpel / knives / saw Inks / dyes Cassettes / lids Biopsy pads / tissue Filter bags Weighing scales
- 11. Cut-up dictation • “Morphology” computer system • “Dragon” dictation system • Hands-free • Just scan the barcode and away we go!!
- 12. Specimen Categories A B C Specimens only requiring transfer from container to tissue cassette. D E Dissection and sampling required needing a moderate level of assessment. Specimens requiring transfer but with standard sampling, counting, weighing or slicing. Simple dissection required with sampling needing a low level of diagnostic assessment and/or preparation. Specimens requiring complex dissection and sampling methods
- 13. Category A Specimens Breast core biopsies Endometrium Colonic series
- 14. Category B Specimens Small lipoma Small skin biopsy Cervical LLETZ
- 16. Category D Specimens Pigmented skin lesions Large Intestine (Crohn’s) C/D C/D Skin with markers Salivary gland tumour
- 17. Category E Specimens Breast cancer Thyroid (medullary Ca) Testis (seminoma) Uterus (endomet. Ca)
- 19. What does the pathologist need to know? Provide good descriptions - say what you see!! • Shape • Colour • Texture • Dimensions • Weight • Distances from margin(s) • Orientation markers • Cut surface appearance etc.... • Keep your fingers crossed for good clinical history
- 20. Doctors’ handwriting!! “dysplasia”? OR “lymphoma”? Breast Ca....”Steroids”? OR “Stomach”? “Nothing” suspicious OR “Notably” suspicious?
- 21. Simple transfer Cervical biopsy Prostate cores
- 22. Specimen Sampling • Literally, taking a sample of the tissue • Representative • Generally, fewer blocks required if the tissue looks uniform throughout (for benign cases) • Sampling “rules”
- 23. Sampling rules: prostate chips • If the chippings weigh 12g or less, the entire specimen must be processed • If the chippings weigh more than 12g, a minimum of 6 cassettes must be processed Prostate chips (19g) Sampled in 8 cassettes: First 12g = 6 cassettes • For every 5g over 12g, one more cassette must be processed 19g = 7g over 12g 1 cassette per 5g over = 2 more cassettes.
- 24. Simple dissection Specimen: Skin from back Clinical details: Sebaceous cyst
- 29. Inking • Resection margins • Embedding instructions • Orientation • Distinguish between samples • Identify the cut surface • Acetic Acid
- 30. Inking resection margins Pigmented lesion Cervical cone
- 31. Embedding Instructions Ink dots instruct the embedder to embed the tissue a certain way.
- 32. Orientation - which way up? • Anatomical
- 33. Orientation - which way up? • Clockface
- 34. 3 o’clock marker Clinical Data: Suture marker at 3 o’clock.
- 35. “12 o’clock” marker Clinical Data: Tag suture at 12 o’clock. ?
- 37. Mapping on a larger scale Cystoprostatectomy Prostate Ureter Red = Right Green = Left Posterior Anterior bladder bladder
- 38. Cassette sizes
- 39. Calcified / firm tissue Most common: • Femoral head • Bone Marrow Trephine • Ethmoid mucosa / nasal polyps (cartilage) • Nail • Hardened cysts
- 40. Softening • For bony / hard tissue: 10% Formic Acid • For nail: Phenol or hair removal cream.
- 41. Firm tissue testing methods • X-ray - Expensive / ? bench space, but very accurate • Chemical end-point test (Ammonium Hydroxide/Ammonium Oxalate) - very time consuming, but accurate • Physical manipulation - not very accurate, may damage the specimen, but simple and inexpensive
- 42. Cutting instructions • • • • • • • Levels Special stains Unstained Sections Serial sections Alopecia protocol MM sentinel lymph node Hirschprung’s protocol
- 43. Specimen Storage • Ventilated storage units • Largest buckets lower shelves • Units are in date (week) order • 5-weeks’ worth of storage • Only authorised specimens are discarded after 5 weeks • Any outstanding cases are stored separately until further notice
- 44. Processing Formalin → Alcohol → Xylene → Wax Wax Xylene Formalin Alcohol
- 46. Embedding The immortalisation of tissue presentation
- 47. Embedding Centre Molten wax Used lids Heated chambers Wax flow adjuster Hot surface Cold plates Wax dispenser
- 48. Embedding tools
- 49. Embedding process Dispense wax Cool in place Align tissue Cassette on
- 50. Embedding process ID bead Top-up wax Leave to set Cool plate
- 51. Embedding tips • Always keep your eye on the tissue: even for the most careful embedders, tissue can ping like tiddlywinks. Make sure you see where it lands!! • Ink dots: usually used to instruct the embedder to embed the tissue a specific way. Make sure you know your own lab’s protocol. • Hide-and-seek: open lids / sponges carefully - tissue often sticks to them. ~ why it’s important for the embedder to know number of bits in the cassette • Cleanliness: always watch out for potential carry-over!!
- 53. Imagination
- 54. Thank you www.slideshare.net/DellaThomas della.thomas@unilabs.com www.micro2tele.com @dellybean (Della Thomas) @HistoQuarterly (Histology Blog) www.facebook.com/histoquarterly