Gastrointestinal Tract Cytology 2

Gastrointestinal Tract Cytology 2

• Programme Learning Outcomes (PLOs): The BBMS program aims to develop skills in analyzing, validating medical lab findings, performing and supervising procedures, collaborating with professionals, demonstrating ethical conduct, presenting information coherently, solving problems, demonstrating lifelong learning principles, and managing laboratory activities.
• Course Learning Outcomes (CLOs): CLO1 – discuss cytopathology techniques; CLO2 – integrate cytopathology foundational knowledge for sample collection, staining, and screening; and CLO3 – prepare reports for cytopathology according to a format.
• Lesson Learning Outcomes: Upon completing the lesson, students will be able to discuss sample collection, preparation, and staining techniques of gastrointestinal tract samples. They will also distinguish cytology features for normal, non-malignant, and malignant gastrointestinal tract conditions
• Lesson Outline: The lesson covers an overview of gastrointestinal tract cytology (GIT), GIT sample collection and smear preparation, cytological examination of the esophagus, stomach, and intestinal portions.
• Overview of GIT Cytology: Clinical indications include suspected malignancy, dysplasia screening (e.g., Barrett's esophagus), and suspected infections. GIT cytology is complementary to tissue biopsy.
• Sample Collection: Sites for cytological sampling include the upper GIT (esophagus, stomach, small intestine), and lower GIT (rectum, anus). Methods like endoscopic direct brushing, endoscopic fine-needle aspiration, and balloon sampling are used.
• Sample Preparation: Smear material is rolled or spread onto a slide, fixed in 95% alcohol followed by air-drying if needed.; LBC samples must follow manufacturer's instructions.
• Staining Methods: Methods discussed include Papanicolaou, Romanowsky staining, May-Grunwald-Giemsa (MGG), and immunocytochemistry. MGG (nucleus: purple; cytoplasm: greyish purple/blue) is a notable stain.
• Cytological Examination of GIT Samples: Slides are examined under low magnification to assess cellularity, arrangements (flat sheets, 3D clusters, isolated cells), and smear background (clean, inflammatory, necrotic).
• Cellular Arrangement: Cells in reactive processes exhibit flat cohesive sheets while neoplastic cells (benign/malignant) tend to aggregate in 3D clusters.
• Smear Background: A clean background suggests a benign process. Numerous necrotic ghost cells without much inflammation indicates malignancy potential.
• High Magnification Examination: Cytologic evaluation focuses on cytoplasmic characteristics and nuclear features.
• Benign vs. Malignant: Benign processes exhibit uniformity in cellular arrangement, nuclear size/shape, and nucleoli number. Malignant neoplasms show haphazard arrangement, irregular cell/nuclear features, and lack of distinct nucleoli.
• Cytological Examination of Esophagus: Conditions examined include infections, epithelial repair, Barrett's esophagus (BE) & dysplasia, squamous cell carcinoma (SCC), adenocarcinoma (adenoCA), and their cytologic presentations (e.g., goblet cell morphology for BE, nuclear characteristics for dysplasia and adenoCA, keratinization for SCC).
• Normal Esophageal Morphology: Superficial and intermediate squamous cells are present, distinguished by abundant cytoplasm and small/pyknotic vs. abundant cytoplasm & vesicular nuclei.
• Esophageal Infections: Infections like Candida are common, while Herpes simplex can feature multinucleation, nuclear molding, ground-glass nuclei, and intranuclear inclusions.
• Epithelial Repair in Esophagus: Characterized by cohesive sheets and uniform/enlarged nuclei with prominent nucleoli, evident mitoses, background inflammation, and atypical stromal cells (as part of the repair process). Radiation-induced changes include cellular/nuclear enlargement, multinucleation, and cytoplasmic/nuclear vacuolization.
• Barrett's Esophagus (BE): Normal stratified squamous epithelium is substituted by columnar epithelium; increased risk of intestinal-type adenocarcinoma (presence of goblet cells)
• BE - Findings: Goblet cells (single large vacuoles displacing nuclei, Swiss-cheese/honeycomb appearance; mucin stains, pseudogoblet cells). Barrett's epithelium displays displaced/crescent-shaped nuclei against the basal membrane.
• Dysplasia of BE: Grading of dysplasia (low-grade: crowded stratified cells, mild nuclear atypia) and (high-grade: crowded/isolated cells, significant nuclear atypia, and pleomorphism) is significant.
• Adenocarcinoma of Esophagus: Esophageal adenocarcinoma is often located in the mid/distal esophagus (arising from BE). Characteristic cytologic features include more abnormal cells, marked nuclear atypia, and macroscopic findings (fungating, ulcerating lesions). Tumor diathesis and atypical nuclear features (enlargement, hyperchromasia, uneven nuclear membrane) are evident.
• Squamous Cell Carcinoma (SCC) of Esophagus: The most common esophageal malignancy. Features (differentiating well vs. poorly differentiated): well-differentiated SCC exhibits hyperchromatic/pyknotic nuclei; poorly differentiated displays less keratization/nuclear angularity/coarseness in chromatin and increased pleomorphism.
• Cytological Examination of Stomach: Focuses on infections, dysplasia, and adenocarcinoma.
• Normal Stomach Morphology: Gastric surface mucous cells, honeycomb pattern, and columnar cells in a palisading arrangement.
• Stomach Infections: Helicobacter pylori (faintly basophilic, S-shaped rods). A typical mycobacteria are present in macrophages.
• Gastric Dysplasia & Adenoma: Both are precursor lesions and distinguished by flat/polypoid appearance, cytologic features depend on dysplasia degree; cytological features of high grade dysplasia include dyshesion and irregular cellular arrangement.
• Gastric Adenocarcinoma: Two main types—intestinal (highly cellular) and diffuse (signet ring cells). Cytomorphology of gastric adenocarcinoma displays small groups/isolated cells, vacuolated cytoplasm, single large vacuole presence, and crescent-shaped/angulated, hyperchromatic nuclei.
• Cytological Examination of Small Intestine: Focuses on infections and adenoma/adenocarcinoma; normal morphology includes absorptive cells (fine granular/vacuolated cytoplasm) and goblet cells (single large mucin vacuoles & crescent-shaped nuclei).
• Small Intestine Infections: Giardia lamblia (flat, gray, pear-shaped, binucleate with 4 pairs of flagella) and Microsporidium (aggregates of brightly eosinophilic rod-shaped/ovoid organisms) are examples of infections detected and identified cytologically.
• Duodenal Adenoma & Adenocarcinoma: Duodenal adenoma displays cohesive 3D clusters of crowded cells, increased NCR/absence of goblet cells, and characteristic palling and molding of elongated nuclei; Duodenal adenocarcinoma displays higher cellularity, increased dyshesion, and marked nuclear atypia/pleomorphism.
• Anal Lesions: Anal squamous cell carcinoma is uncommon. Screening, using anal pap test, is used for detection of cancer/precursors. The Bethesda terminology is crucial in reporting anal findings.
• HSIL (Anal Pap Smear): HSIL cells show nuclear enlargement, membrane irregularity, and chromatin coarsening – analogous to cervical specimens.

Comparison of Cytologic Features

• Tables comparing reactive changes, dysplasia, and adenocarcinoma in terms of various features including 3D cluster arrangement, dyshesion, atypical cell presence, mitoses, chromatin appearance, nuclear pleomorphism, and overlap/irregularity in spacing.