In the cervix there is a nice transition from the rough and tough squamous epithelial cells of the outside world (vagina) to the squishy secretory columnar epithelial cells of the inside (uterus). Over time the junction between these two cell types moves towards the inside (more squamous cells) and this is normal metaplasia. This is not to be confused with dysplasia, which is the transformation of normal squamous cells to less differentiated cells.
When women get colposcopies the examiner is looking for dysplasia, and two of the tricks they have up their sleeves to make the dysplasia more apparent are vinegar and iodine.
Both rely on the fact that dysplastic cells are more active and have a much larger nucleus:cytoplasm ratio.
- When vinegar (acetic acid) is applied, the cells become dehydrated, and the nuclei reflect more light. This makes the cells with larger nuclei more prominent because they appear more white. This includes dysplastic cells and cells infected with HPV.
- With an iodine solution (Lugol’s iodine) the iodine binds to glycogen in cells making them appear dark brown. Healthy columnar cells don’t have glycogen and due to their small amount of cytoplasm, dysplastic and HPV-infected cells don’t either.
Using these two techniques can help differentiate areas of dysplasia and guide sampling biopsies.
TNM Prostate Cancer Staging
- Tx: primary tumor cannot be assessed
- T0: no evidence of a primary tumor
- T1: clinically in apparent tumor neither palpable not visible by imaging
- T1a: incidental histology – <5% of resected tissue
- T1b: incidental histology – >5% of resected tissue
- T1c: increased PSA and subsequent identification by needle biopsy
- T2: tumor confined within prostate
- T2a: half of one lobe or less
- T2b: greater than half of one lobe, none in other
- T2c: both lobes
- T3: tumor extends through capsule
- T3a: extracapsular extravasion
- T3b: tumor invades seminal vesicles
- T4: tumor is fixed or invades adjacent structures other than the seminal vesicles (external sphincter, rectum, bladder, lavator muscles, and/or pelvic wall).
- Nx: regional lymph nodes not assessed
- N0: no lymph node metastasis
- N1: metastasis in regional node(s)
- M0: no distant metastasis
- M1a: non-regional lymph node(s)
- M1b: bone(s)
- M1c: other sites with or without bone disease
- When more than 1 site of metastasis is present give advanced stage (M1c) is given
So a patient has skin cancer (duh duh duuuuh). How much of a margin should you give in your excision?
Like all things, this depends on the type of skin cancer
- Basal Cell Carcinoma (BCC)
- Squamous Cell Carcinoma (SCC)
Low-risk BCCs: 4 mm (high-risk: Mohs surgery)
Low-risk SCCs: 4 mm (high-risk: Mohs surgery)
Melanomas: depends on the tumour (T) stage, which is dependent on tumour thickness
- T1 (<1 mm): 1 cm margin (92% 10 year survival)
- T2 (1-2 mm): 2 cm margin (80% 10 year survival)
- T3 (2-4 mm): 2 cm margin (63% 10 year survival)
- T4 (>4 mm): 2 cm margin (50% 10 year survival)
- Though it might seem counterintuitive that once you’re past 1 mm thickness, you don’t have a bigger margin, but larger margins haven’t been shown to increase survival