Cytology of common skin tumors.
• Fine needle biopsy (aspirates): includes "aspiration" and "non aspiration" techniques
o Preferred method for masses
• Impression smears: directly from lesion, or using a biopsy sample
• Scraping: flat lesions, scirrhous tumors
• Swab: vaginal vault, fistulous tracks
• 21-25 gauge needle
o 22 ga is a good compromise
o > 21 causes "cores"/blood contamination
• 3-20 ml syringe
o 12 ml is a good compromise
• Needle and syringe used
• Cells are obtained via vacuum from syringe
• Works well for same masses as aspiration
• Improves diagnostic quality for
o Deep masses
o Firm masses which do not exfoliate well
o Vascular organs/masses (liver/HSA)
• Cells obtained by "stuffing" the needle in a pecking fashion
• External lesions or biopsy specimens
• Surface contamination is a problem
• Perform an aspirate of ulcerated lesions as well
Pitfalls of making imprints:
1. Vertical imprints: Broken cells
• Cells are broken if imprints are made vertically: up and down motion
• Result is "road kill" because individual cells are broken
• Preps are better when slide or sample is rolled because the cells are "draped" rather than pulled apart.
2. Poor representation of the lesion
• Surface does not adequately represent lesion
• Some organisms are more abundant in lesions
• Surface lesions or biospy specimens
• High cell yield
• Should aspirate masses as well
• Scalpel blade collects cells
• Fistulous tracts
• Vaginal swabs
• Saline moistened cotton swab
• Roll on the slide
Methods of preparation
• Squash preparation
• Pull preparation (blood smear technique)
• Goal: To create at least one area on the slide that contains a monolayer of cells of relatively high density.
• Submit 2-3 slides unstained
• Air dry only!!!
o No wet fixation using formalin or ethanol
• Stain 1-2 on-site to evaluate quality, and send those slides as well!
• Protect from formalin fumes, moisture and aging
• Not enough cells
• Blood contamination
• Ruptured cells: overzealous preparation
• Cytology not representative of lesion
o Surface contamination of ulcerated masses
o Wrong organ aspirated: for instance, salivary gland instead of lymph node
• Epidermal, dermal, or subcutaneous mass lesions that are easily accessible to aspiration cytology
• To direct next step of therapy or diagnostics (at the minimum)
• To definitively diagnose the cause of the lesion
• To advise owners of most probable process, give them more choices more quickly
• What is the process that is causing the expansion of tissue making a lump?
o What is the treatment?
o What is the prognosis?
• Is the sample adequate? Enough cells, properly made, properly stained, correct organ.
• What is the general process? eg inflammatory or neoplastic
• What is the etiology if inflammatory?
• What is the identity of neoplastic tissue?
• What is the malignant potential of neoplastic tissue?
• Is the sample representative?
• Is the sample cellular?
• Were the cells preserved in sample preparation?
• Is the staining appropriate?
• Are there areas of the slide that are acceptable for evaluation?
• Cells do not exfoliate well (sarcoma) or schirrous carcinoma
• Lesion is small, needle placement difficult
• Inappropriate placement of needle, not enough different placements
• Necrotic center of tumor
• Inadequate vacuum (timid sampling)
• Nuclei should be dark purple
• Cytology samples sent with formalin are at risk
• Cytology samples not stained within 3 days are at risk!
• Identify leukocytes
• Search for and identify etiologic agents