Lumps and bumps: cytology of common skin tumors (Proceedings)

Obtaining the sample

• 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

Equipment

• 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

"Aspiration" techniques

• Needle and syringe used

• Cells are obtained via vacuum from syringe

Non aspiration technique

• 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

For both methods sample is prepared by expelling needle contents onto the slide by positive pressure (air filled syringe)

Imprints

• 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

Ulcerated lesions- neoplasia

• Surface does not adequately represent lesion

Ulcerated lesions- Organisms

• Some organisms are more abundant in lesions

Scrapings

• Surface lesions or biospy specimens

• High cell yield

• Should aspirate masses as well

• Scalpel blade collects cells

Swabs

• Fistulous tracts

• Vaginal swabs

• Saline moistened cotton swab

• Roll on the slide

For all methods, the sample then needs to be adequately prepared ON THE SLIDE:

Methods of preparation

• Squash preparation

• Pull preparation (blood smear technique)

• Combination

• Goal: To create at least one area on the slide that contains a monolayer of cells of relatively high density.

Submission of samples

• 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

Common problems

• 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

Lumps and bumps

• Epidermal, dermal, or subcutaneous mass lesions that are easily accessible to aspiration cytology

Goal of aspiration cytology of lumps and bumps

• 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

Overall question

• What is the process that is causing the expansion of tissue making a lump?

• Subquestions:

     o What is the treatment?

     o What is the prognosis?

Investigative approach: How are we going to make sure to come to the right conclusions?

• 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 adequate?

• 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?

Problem of not enough cells

• 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)

Staining appropriate?

• Nuclei should be dark purple

• Cytology samples sent with formalin are at risk

• Cytology samples not stained within 3 days are at risk!

Inflammation

• Identify leukocytes

• Search for and identify etiologic agents