Pathology Spot Exam Revision: Lymphoma, OmpathStudy

Mount Kenya University — School of Medicine, Department of Pathology Bachelor of Medicine and Bachelor of Surgery (MBChB) — Year 3 Unit: MBPA 3500 — Pathology Practical Exam Type: Spot/Practical Examination Papers Referenced: Special/Supplementary 2025/2026 & Regular 2023/2024 Compiled: June 2026 Purpose: Revision Q&A for Pathology Practical Spot Examination — Part 2 of 2 --- This article is Part 2 of a 2-part revision series compiled from past MKU Pathology Practical Spot papers. Questions are in point-form Q&A format for easy revision. Where a topic appears in more than one paper it is marked (×2). Image-dependent questions have been excluded. --- 13. Burkitt Lymphoma (×2) Q: Most likely diagnosis — rapidly growing jaw mass in a 6-year-old Kenyan child? Endemic Burkitt Lymphoma Highly aggressive B-cell non-Hodgkin lymphoma Classically presents as rapidly growing jaw/facial bone tumour in children from equatorial Africa Q: Primary infectious cause/risk factor? Epstein-Barr Virus (EBV) — present in nearly 100% of endemic cases Chronic malaria is a major co-factor (reduces resistance to EBV) Q: Classic histological finding? "Starry sky" appearance Rapidly dividing neoplastic uniform B lymphocytes (the "sky") Interspersed with large pale tingible body macrophages (the "stars") clearing apoptotic cells Q: Specific genetic finding? Chromosomal translocation t(8;14) Moves c-MYC oncogene (chromosome 8) to immunoglobulin heavy chain promoter (chromosome 14) Leads to uncontrolled cell proliferation --- 14. Pituitary Adenoma Q: What is seen on the sagittal MRI? Mass within the sella turcica of the sphenoid bone Pituitary adenoma — benign tumour of the anterior pituitary gland Q: Classic neurological/visual symptom? Bitemporal hemianopsia (loss of outer visual fields in both eyes) Caused by macroadenoma expanding superiorly and compressing the optic chiasm Q: Most common hormone secreted by functioning pituitary adenoma? Prolactin Prolactinoma presents with: galactorrhoea, amenorrhoea, infertility --- 15. Gangrenous Appendicitis Q: What is the most likely diagnosis? Gangrenous appendicitis Blackening of tissue = transmural necrosis from compromised vascular supply Q: Gross pathological findings? Diffuse dark-brown to black discoloration of serosal surface Extensive tissue necrosis and congestion Loss of blood supply Q: Clinical signs and complications? Severe right lower quadrant (RLQ) pain Rebound tenderness High fever Leukocytosis High risk of perforation → abscess or generalised peritonitis Q: Expected microscopic findings? Transmural neutrophilic infiltration Extensive liquefactive necrosis Haemorrhage Fibrinopurulent exudate on serosal surface --- 16. Haemoglobin Electrophoresis (×2) Q: Principle of haemoglobin electrophoresis? Separation of different haemoglobin types (HbA, HbS, HbC etc.) Based on electrical charge and migration in an electric field Q: What does presence of HbS band indicate? Sickle Cell Disease or Sickle Cell Trait Q: How does Hb M-Iwate behave on electrophoresis? Alkaline gel: anodal to HbA Acid gel: indistinguishable from HbA Isoelectric focusing: appears brown before chemical application (HbA appears red) Dried gel: migrates between HbF and HbS Q: Haemoglobin patterns and their patients? HbSS — Sickle Cell Disease HbAS — Sickle Cell Trait HbAA — Normal --- 17. FISH (Fluorescence In Situ Hybridisation) Q: What technique is shown? FISH — Fluorescence In Situ Hybridisation Q: What do the colours represent? Blue regions: cell nuclei stained with DAPI (binds to DNA) Pink/red spots: fluorescent probes hybridised to specific DNA sequences Q: Metaphase vs interphase FISH — which is shown? Interphase FISH DNA contained within intact non-dividing nuclei (not condensed into chromosomes) Q: What does finding 3–4 red signals per nucleus indicate? Polysomy or aneuploidy (e.g. trisomy or high-level copy number gains) Q: Clinical applications of interphase FISH? Prenatal screening: detecting trisomies 21, 18, 13 Oncology: gene amplifications (HER2 in breast cancer, MYCN in neuroblastoma) Haematopathology: diagnosing leukaemias/lymphomas via genetic rearrangements Q: Advantages over standard karyotyping? Speed: results in 24–48 hours vs 1–2 weeks for karyotyping Can be performed on non-dividing cells including FFPE sections Detects small microdeletions and gene amplifications below light microscopy resolution --- 18. Glucometer / Blood Glucose Monitoring (×2) Q: What instrument is shown? Glucometer (Wellion CALLA Light model) Portable device for self-monitoring of blood glucose (SMBG) Q: Principle of the glucometer? Electrochemical (amperometric) principle Test strip contains glucose oxidase enzyme Reacts with blood glucose → produces gluconic acid + hydrogen peroxide Electrons generate electric current proportional to glucose concentration Meter converts current to digital reading Q: Normal blood glucose reference ranges? Fasting normal: 3.9–5.6 mmol/L (70–100 mg/dL) Impaired fasting: 5.6–6.9 mmol/L (100–1