IST Internal Assignment 3 - Cytology (2024 Batch) - Model Answers

CASE 1

Q1. What is the Diagnosis?

Q2. Describe the Slide Findings

1. Background - turbid/creamy aspirate; smear background shows necrotic debris and proteinaceous material
2. Inflammatory cells - large numbers of degenerated and intact neutrophils (pus cells) - the hallmark finding
3. Macrophages/histiocytes - scattered, with engulfed cellular debris (phagocytosis)
4. Cellular debris - abundant necrotic material in the background
5. Absence of epithelial cell clusters or granulomas - distinguishes it from carcinoma or tuberculosis
6. Bacteria - may be visible (Gram stain shows cocci or bacilli depending on causative organism)
7. Red blood cells - scattered in background

Note for the diabetic patient: Staphylococcus aureus is the most common causative organism of soft tissue abscesses; in diabetics, consider also Gram-negative organisms and anaerobes. Culture and sensitivity of aspirated pus is mandatory.

CASE 2

Q1. What is the Diagnosis?

• Large hyperchromatic irregular nuclei (malignant nuclear features)
• Tadpole cells - elongated tumor cells with a broad head and tapering tail; pathognomonic of keratinising SCC
• Tumor diathesis background (neutrophils + necrotic debris) indicating invasion through tissue

Q2. Aetiology of this Condition

• High-risk oncogenic types: HPV 16 and HPV 18 together account for ~70% of all cervical cancers
• Other high-risk types: HPV 31, 33, 45, 52, 58
• Mechanism: HPV integrates into the host genome and expresses E6 protein (inactivates p53 tumour suppressor) and E7 protein (inactivates RB tumour suppressor), leading to uncontrolled cell proliferation and suppression of apoptosis

Q3. Risk Factors

Q4. How to Prevent This Condition

• Bivalent vaccine (Cervarix): Covers HPV 16 & 18
• Quadrivalent vaccine (Gardasil): Covers HPV 6, 11, 16, 18
• Nonavalent vaccine (Gardasil 9): Covers HPV 6, 11, 16, 18, 31, 33, 45, 52, 58
• Recommended for girls aged 9-26 years (ideally before sexual debut)
• Also recommended for boys to reduce HPV transmission
• Most effective before HPV exposure

• Pap smear (Papanicolaou test): Detects pre-cancerous lesions (LSIL, HSIL/CIN) before invasive cancer develops; recommended every 3 years from age 21 or within 3 years of first sexual activity
• HPV co-testing: Combined with Pap smear every 5 years (ages 30-65) for higher sensitivity
• VIA (Visual Inspection with Acetic Acid) - low-cost screening in resource-limited settings

• Barrier contraception (condoms) - reduces HPV transmission
• Reducing number of sexual partners
• Avoiding smoking
• Treating HIV and other immunocompromising conditions
• Early treatment of premalignant lesions (CIN) by LEEP, cryotherapy, or cold knife conization

CASE 3

Q1. Diagnosis

1. Epithelioid cell granulomas - epithelioid histiocytes with "slipper-shaped" (elongated, curved) nuclei, often in clusters
2. Langhans-type giant cells (may or may not be present)
3. Caseating necrotic debris in the background

Q2. Aetiology

• Primary causative organism: Mycobacterium tuberculosis (human type) - most common
• Other Mycobacteria:
  • Mycobacterium bovis (bovine type - from unpasteurised milk; less common now)
  • Non-tuberculous mycobacteria (NTM): M. scrofulaceum, M. avium-intracellulare complex (especially in immunocompromised/HIV patients)

• Primary infection in lungs or oropharynx leads to spread via lymphatics to regional lymph nodes
• Alternatively, haematogenous spread from a primary focus
• Macrophages engulf the bacilli but cannot destroy them; this triggers formation of epithelioid granulomas
• Central caseation necrosis develops due to cell-mediated hypersensitivity (Type IV)
• Nodes may enlarge, become matted (periadenitis) and eventually soften/liquefy (cold abscess)

Q3. Relevant Investigations

First-line treatment (once diagnosis confirmed): 2HRZE / 4HR - Isoniazid (H), Rifampicin (R), Pyrazinamide (Z), Ethambutol (E) for 2 months intensive phase followed by 4 months continuation phase.