Gastrointestinal Tract Cytology

Gastrointestinal Tract Cytology

Gastrointestinal Tract Cytology

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GIT Cytology: Basics - Scope & Smears

  • Scope: Rapid diagnosis: neoplasia, inflammation, infections (H. pylori, CMV, Candida). Guides therapy.
  • Specimen Types:
    • Exfoliative: Brushings (esophagus, stomach, bile duct), washings, ERCP-guided.
    • Aspiration: FNA (palpable/intraop), EUS-FNA (deep lesions: pancreas, LNs - gold standard).
  • Smear Prep: Direct (quick), Cytospin (concentrates cells), Liquid-Based Cytology (LBC - uniform, less debris).
  • Stains: Pap (nuclear detail), MGG/Diff-Quik (cytoplasmic, matrix), special (PAS-mucin, Grocott-fungi). Microscopic view of GI cytology smear

⭐ EUS-FNA offers high diagnostic yield (>85% sensitivity, >95% specificity) for solid pancreatic lesions.

Esophageal Cytology: Lesions - Gullet Gazing

  • Normal Cells: Predominantly superficial squamous cells; few parabasal/intermediate.
  • Benign Conditions:
    • Infections:
      • Candida: Pseudohyphae, budding yeasts. Inflammatory background.
      • HSV: 📌 3 'M's (Multinucleation, Molding, Margination), Cowdry type A inclusions.
      • CMV: Large cells with "owl's eye" intranuclear inclusions; granular cytoplasmic inclusions.
    • Reflux Esophagitis: Neutrophils, eosinophils, reactive squamous atypia, parakeratosis.
    • Barrett's Esophagus: Intestinal metaplasia: presence of goblet cells. Precursor to adenocarcinoma.

      ⭐ Goblet cells are the diagnostic hallmark of Barrett's esophagus, indicating intestinal metaplasia.

  • Malignant Tumors:
    • Squamous Cell Carcinoma (SCC):
      • Cellular smears; pleomorphic squamous cells (single/clusters).
      • Irregular, hyperchromatic nuclei, ↑N/C ratio.
      • Keratinization (dense orangeophilic cytoplasm), "tadpole" or "fiber" cells. Tumor diathesis.
    • Adenocarcinoma (AdenoCa):
      • Glandular clusters, acini, or papillae.
      • Pleomorphic columnar cells, vacuolated cytoplasm, prominent nucleoli.
      • Signet ring cells may be present. Typically arises from Barrett's.

Esophageal adenocarcinoma cytology and histology

Gastric Cytology: Findings - Stomach Stories

  • Normal Gastric Cells:
    • Superficial columnar: Honeycomb sheets, bland nuclei.
    • Deep glandular: Smaller, rounder, tight clusters.
  • Inflammation & Reactive Changes:
    • Neutrophils, lymphocytes, plasma cells.
    • Nuclear enlargement, prominent nucleoli, reparative atypia.
    • Helicobacter pylori: Curved/S-shaped bacilli on mucus or epithelial surface.
  • Intestinal Metaplasia:
    • Presence of goblet cells (key diagnostic feature).
    • +/- Brush border.
  • Dysplasia (Pre-malignant):
    • ↑ N/C ratio, hyperchromasia, irregular nuclear membranes, pleomorphism.
    • Loss of cellular polarity, architectural disarray.
    • Graded: Low-grade (LGD) vs. High-grade (HGD).
  • Gastric Adenocarcinoma:
    • Intestinal type: Glandular/acinar structures, pleomorphic cells, dirty necrotic background.
    • Diffuse type (Signet-ring cell carcinoma): Discohesive cells, large intracytoplasmic mucin vacuole pushing nucleus to periphery.
  • MALT Lymphoma:
    • Monotonous population of small to medium-sized atypical lymphocytes.
    • Lymphoepithelial lesions (infiltrating glands).

Signet ring vs intestinal type adenocarcinoma

⭐ > Signet-ring cells in gastric cytology, with their eccentric nucleus and mucin-filled cytoplasm, are a hallmark of diffuse-type gastric adenocarcinoma, often associated with linitis plastica.

Pancreato-Biliary Cytology: FNA & Brushings - Deep Dive Diagnostics

  • Sampling: Endoscopic Ultrasound-guided FNA (EUS-FNA) for pancreas; Endoscopic Retrograde Cholangiopancreatography (ERCP)-brushings/FNA for biliary tree.
  • Pancreatic Ductal Adenocarcinoma (PDAC):
    • Cellular smears: 3D clusters, single malignant cells.
    • Nuclear atypia: Pleomorphism, irregular membranes, prominent nucleoli, hyperchromasia.
    • Often mucinous background.
    • 📌 Mnemonic: "Pancreatic Pleomorphism, Prominent nucleoli".
  • Cholangiocarcinoma:
    • Atypical glandular cells: Sheets, clusters, or single cells.
    • Nuclear features: Crowding, hyperchromasia, irregular contours.
    • Often less cellular & pleomorphic than PDAC.
  • Other Lesions:
    • Pancreatic Neuroendocrine Tumors (PNETs): Plasmacytoid cells, "salt-and-pepper" chromatin.
    • Cystic lesions (e.g., IPMN, MCN): Mucin, variable epithelial atypia.
  • Challenges: Differentiating reactive atypia from low-grade malignancy.

⭐ KRAS mutations are detected in >90% of pancreatic ductal adenocarcinomas and can be assessed on cytology samples.

Pancreatic Adenocarcinoma FNA Cytologyoka

High‑Yield Points - ⚡ Biggest Takeaways

  • Barrett's esophagus: goblet cells confirm intestinal metaplasia in esophageal samples.
  • H. pylori: identifiable in gastric cytology, linked to gastritis and ulcers.
  • Gastric adenocarcinoma: features signet ring cells, high N:C ratio, nuclear atypia.
  • Esophageal SCC: shows keratinization, pleomorphism, and orangeophilic cytoplasm.
  • GISTs: spindle cells and CD117 (c-KIT) positivity are diagnostic hallmarks.
  • NETs: "salt and pepper" chromatin; positive for synaptophysin & chromogranin.
  • Viral cytopathy: CMV (owl's eye inclusions), HSV (multinucleation, molding).

Practice Questions: Gastrointestinal Tract Cytology

Test your understanding with these related questions

Which of the following is the most common tumor of the pancreas?

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Flashcards: Gastrointestinal Tract Cytology

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Class II PAP consists of CIN grade _____ and Bethesda grade ASCUS/inflammatory or HPV

TAP TO REVEAL ANSWER

Class II PAP consists of CIN grade _____ and Bethesda grade ASCUS/inflammatory or HPV

inflammatory

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