The Importance of Biopsies

• Medical graduates can gain essential knowledge and skills to understand the importance of biopsies by equipping themselves on when to perform them, how to handle biopsy specimens, and key do’s and don’ts for optimal clinical outcome.
• A definitive diagnosis relies on various diagnostic methods, including radiographs, clinical laboratory procedures, and histological examination of tissue specimens.
• A biopsy involves removing tissue or other material from a living body for microscopic examination.

Purpose of Biopsy

• Helps verify a clinical impression and assists in formulating a treatment plan during treatment evaluation.
• Determines whether a disease is a local or systemic process.
• Aids in early and accurate diagnosis of the disease process.

Biopsy Techniques

• Excisional biopsy: Total removal of a small lesion with adequate margins of normal-appearing tissue on all sides.
• Incisional Biopsy: Removal of a portion of a lesion, providing representative specimen(s).

Additional Biopsy Methods

• Punch Biopsy: A portion of a lesion is removed via punch.
• Aspiration Biopsy: Removal of contents from a cyst or cyst-like lesion to determine the nature of the lesion.
• Curettage Biopsy: Lesion removal by scraping, typically used for intraosseous lesions.
• Needle Biopsy: Used for deep-seated lesions.
• Exfoliative Cytology: Involves sampling only surface cells.
• Brush Biopsy (Oral CDx): Provides a completely trans-epithelial sample.

Biopsy Types

• Cytology sampling
  • Exfoliative (brush)
  • Liquid
  • Fine needle aspiration
• Tissue sampling
  • By excision (direct, open surgical, video-assisted)
  • Core needle biopsy
  • By endoscopy

Biopsy Guidance

• Visual guidance
  • Superficial localization
  • Body cavities
  • Hollow organs
• Guidance by imaging
  • Deep localization

Cytology Sampling Details

• Result: Cell samples are spread on a glass slide which yields a SMEAR
  • Contains cellular elements from the lesion and surrounding tissue, with the ratio depending on sampling technique and lesion type.
  • Background includes blood, inflammatory cells, extracellular substances (mucus, colloid, etc.).
• Provides fast results for bedside diagnosis.
• Sample Processing:
  • Wet fixation using alcohol and staining with Hematoxylin and Eosin (H&E) or Papanicolaou preserves cellular morphology.
  • Air drying combined with Giemsa or Diff-Quick staining offers a fast and simple method but alters cellular morphology.

Exfoliative Cytology

• Specifically used for superficial lesions of hollow organs
• Identifies intraepithelial or invasive tumors in the cervix, small bronchus, biliary duct system
• Sample characteristics include numerous normal or reactive epithelial cells.
  • Can be difficult to discern if cells are reactive or malignant
  • Can be difficult to tell if a lesion is a Dysplasia or an invasive tumor

Cytology of Liquids

• Used on body cavity effusions of neoplastic or inflammatory origin.
• Also used on cyst contents and other fluids than blood (peritoneal, pleural, pericardial, urine).
• Sample characteristics include numerous normal or reactive mesothelial or epithelial cells altered by the liquid environment.
  • Also shows numerous inflammatory cells (neutrophils, histiocytes).
  • Can be difficult to discern if cels are reactive or malignant.

Fine Needle Aspiration (FNA)

• Suited for solitary or multifocal solid lesions.
• Sample primarily contains tumor cells in neoplastic processes.
• Surrounding tissue cellular elements are variably present (e.g., lymphoid cells from a lymph node).
• Contamination from the needle track may occur.
  • For example, intestinal epithelial cells or mesothelial cells may be present if biopsying an abdominal mass.
• Samples may not be representative if targeting is missed or necrosis is present.

Fine Needle Aspiration Technical

• Simple tools are required, such as needles and syringes
• Guidance Methods:
  • Ultrasound is the first choice, offering a simple, fast, real-time image.
  • CT scans are used for lesions not detectable by ultrasound, thoracic lesions, and long procedures, targeting based on a still image.

Tissue Sampling Details

• Yields a slide
• It is time consuming as it take a minimum of 2 days
• Formalin fixation is generally required
  • Fresh samples from skin or kidney should be sent to pathology without delay for immunofluorescent microscopy.
  • Lymphomas should be ideally fresh, frozen samples for molecular techniques.

Tissue Sampling by Endoscopy

• Gastroscopy is used on the oesophagus and duodenum
• Colonoscopy is used on the terminal ileum-anus.
• Laryngoscopy is used on the pharynx-larynx
• Bronchoscopy is used on the trachea-large bronchi.
• Cystoscopy
• Focal lesions (tumors) should have 2-3 representative samples from the periphery or surface of the lesion, avoiding necrosis.
• Diffuse lesions (gastritis, IBD) should use map biopsy.
  • In this, an ideal or representative biopsy includes muscularis mucosae, fixed on a flat surface for better orientation during specimen processing.

Core Needle Biopsy Uses

• For focal lesions (solitary or multifocal) and solid organs Can be an alternative to cytology
• Also used for diffuse lesions in solid parenchymal organs that lead to structural alterations (e.g., glomerular diseases, diffuse hepatic lesions)
• Guided via Ultrasound, CT, MRI, etc.

Cytology vs. Histology

• Cytology: Fast, simple tools, minimally invasive, rare complications, but limited sample and ancillary exams (IHC)

  • Type-Main tumor is found
  • Can discern if a lesion is Low grade/High grade and Invasion is -limited
  • Often the method used before surgery to clarify etiology of metastatic disease

• Histology: Several slides from the sample, ideal for IHC evaluation, but time-consuming processing, more expensive, and invasive, with more lab requirements and complications.

  • More accurate tumor typing and allows Grade-assessment of proliferation and Invasion determination
  • Systemic rx planning and finding special tumours e.g. lymphomas

• Experience is required for both techniques; unsatisfactory samples are of no diagnostic use.

Biopsy Dos

• An accurate and complete clinical history should be submitted.
• Sufficient tissue should be removed to ensure representative material.
• Submit X-rays (or radiologic findings) to the pathologist for osseous lesions.
• Take periodic biopsies if necessary to check for recurrence and follow the course of the lesion. Use sufficient fixative ensuring the entire specimen is covered, maintaining a tissue ratio of 1:10.
• Remove tissue from the periphery or active area rather than the center.
• Formalin is the most common fixative used.
• Employ smooth-jawed tissue forceps, as hemostats can macerate tissue.

Biopsy Don'ts

• Incise a small lesion.
• Use cutlery, can “cook” the tissue.
• Use lasers for small tissue, it distorts the tissue.
• Allow tissue to dry out before fixation.
• Always depend on a single, negative biopsy, several may be necessary from different areas.
• Take specimens from necrotic areas unless bacterial slides are desired.
• Cut into pigmented or vascular lesions.
• Inject local anesthetic directly into the immediate area- it distorts the tissue Use a small mouth container for fixative.