NEET-PG 2020 - Pathology Practice Questions

Q: Why is citrate phosphate dextrose (CPD) better than acid citrate dextrose (ACD) for storage of blood?

Contains phosphate and dextrose. ***Contains phosphate and dextrose*** - CPD contains **phosphate**, which acts as a buffer and helps maintain crucial 2,3-bisphosphoglycerate (2,3-BPG) levels in red blood cells, improving oxygen delivery capacity. - The presence of **dextrose** provides a substrate for glycolysis, which is essential for ATP production and red blood cell viability during storage. - This combination allows CPD to extend blood storage life to approximately **35 days** compared to ACD's **21 days**. *Maintains pH stability during storage* - Both ACD and CPD help maintain pH stability due to their **citrate** content, which acts as an anticoagulant and buffer. - However, CPD's phosphate component offers superior buffering capacity, but pH maintenance alone is not the primary distinguishing advantage. - This is a shared characteristic of both solutions, not the key reason CPD is preferred. *Prevents hemolysis in stored blood* - Both CPD and ACD prevent hemolysis by chelating **calcium**, which prevents coagulation and maintains red blood cell integrity. - While both solutions successfully prevent hemolysis, this is not the distinguishing feature that makes CPD superior. - The primary advantage of CPD lies in its better support of red blood cell metabolism and viability through phosphate and dextrose. *Reduces metabolic activity in stored blood* - This is **incorrect** - the purpose of anticoagulant solutions is to preserve blood components, not to reduce metabolic activity. - The dextrose in CPD is provided precisely to **fuel essential metabolic activity** (glycolysis) to sustain red blood cells during storage. - While refrigeration at 1-6°C slows metabolism, CPD actively supports rather than reduces the metabolic processes necessary for RBC survival.

Q: A middle-aged female presented with a 4cm mass in the upper outer quadrant of the breast. Biopsy showed densely packed cells within large extracellular spaces. Which of the following is the most likely diagnosis of this patient?

Colloid carcinoma of breast. ***Colloid carcinoma of breast*** - This type of carcinoma is characterized by **malignant cells floating in abundant extracellular mucin (colloid)**, which aligns with the description "densely packed cells within large extracellular spaces." - It often presents as a **well-circumscribed mass** and has a generally **good prognosis**. *Tubular carcinoma of breast* - Characterized by **well-differentiated tubules** with open lumens and a single layer of epithelial cells. - It does not typically feature large extracellular spaces filled with mucin. *Medullary carcinoma of breast* - This typically presents as a **soft, fleshy tumor** with syncytial sheets of large anaplastic cells and a prominent lymphoid infiltrate [1]. - It does not involve significant extracellular mucin or large extracellular spaces. *Papillary carcinoma of breast* - This carcinoma is defined by **papillary growth patterns** with fibrovascular cores lined by epithelial cells. - While it can be associated with cystic spaces, these are not typically described as "large extracellular spaces" filled with mucinous material. **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Liver And Biliary System Disease, pp. 455-456.

Q: Patient presented with diarrhoea, poor appetite and malabsorption. His duodenal biopsy was taken which showed crypt hyperplasia, villi atrophy and infiltration of CD8+ T cells in the epithelium. What is the likely diagnosis of the patient?

Celiac disease. ***Celiac disease*** - The combination of **diarrhoea**, **malabsorption**, **villi atrophy**, **crypt hyperplasia**, and **CD8+ T-cell infiltration** in the duodenal epithelium is pathognomonic for celiac disease [1]. - This condition is triggered by **gluten ingestion**, leading to an immune-mediated enteropathy [1], [3]. *Whipple disease* - Characterized by **malabsorption**, fever, arthralgia, and neurological symptoms [2]. - Histologically, it shows **foamy macrophages** containing PAS-positive material (Tropheryma whipplei) in the lamina propria, not primarily CD8+ T-cell infiltration [2]. *Environmental enteropathy* - Also known as tropical enteropathy, it causes **villi atrophy** and malabsorption, particularly in individuals living in areas with poor sanitation. - However, the prominent feature is often a diffuse inflammatory infiltrate, and specific **CD8+ T-cell infiltration** in the epithelium is not as specific as in celiac disease. *Pancreatitis* - Presents with **abdominal pain**, nausea, and vomiting, and can lead to malabsorption due to pancreatic enzyme insufficiency. - Histology of the duodenum would typically be normal, as the pathology primarily involves the **pancreas**, not the duodenal mucosa itself.

Q: A newborn baby presented with a failure to pass meconium in the immediate postnatal period. The pediatrician also notices visible yet ineffective peristalsis, and abdominal distention. A radiological contrast enema demonstrated a narrow conical segment and a dilated proximal bowel. A diagnosis of Hirschsprung disease was made. Which of the following is a cause of the condition in the patient?

Failure of migration of neural crest cells. ***Failure of migration of neural crest cells*** - Hirschsprung disease is characterized by the **absence of ganglion cells** (specifically **Auerbach's and Meissner's plexuses**) in the distal bowel. - This aganglionosis results from the **failure of neural crest cells to migrate** completely into the intestinal wall during embryonic development. *Persistence of embryonic structures in the bowel wall* - This mechanism is associated with conditions like **Meckel's diverticulum**, where a remnant of the **vitelline duct** persists. - It does not explain the absence of ganglion cells or the functional obstruction seen in Hirschsprung disease. *Congenital obstruction due to external factors* - This would involve conditions such as an **annular pancreas**, **bands**, or **malrotation with volvulus**, creating a physical barrier. - Hirschsprung disease is a **functional obstruction** due to neuromuscular dysfunction, not an external compression or blockage. *Abnormal peristalsis due to neural dysfunction* - While there is abnormal peristalsis, the underlying cause is not just **"neural dysfunction"** in a general sense, but specifically the **absence of entire ganglion cell plexuses** within the bowel wall. - This option is too broad and doesn't pinpoint the precise developmental defect.

Q: Transplantation between identical twins-

Isograft. ***Isograft*** - An **isograft** refers to a transplant between **genetically identical individuals**, such as identical twins, thus minimizing immune rejection [1]. - Due to the identical genetic makeup, the recipient's immune system will not recognize the transplanted tissue as foreign, making **immunosuppression unnecessary** [1]. *Xenograft* - A **xenograft** involves transplantation of tissues or organs between **different species**, for example, from a pig to a human. - These grafts typically face severe and rapid **immune rejection** due to significant genetic differences between the donor and recipient species. *Autograft* - An **autograft** is a transplant of tissue from **one part of an individual's body to another part of the same individual**. - This type of graft has no risk of rejection as the tissue is genetically identical to the recipient's own tissue [2]. *Allograft* - An **allograft** is a transplant between **genetically non-identical individuals of the same species**, such as between two non-twin humans. - These grafts always require **immunosuppressive therapy** to prevent rejection due to genetic differences, though rejection rates vary based on HLA matching [1].

Question 1

Why is citrate phosphate dextrose (CPD) better than acid citrate dextrose (ACD) for storage of blood?

Accepted Answer

Contains phosphate and dextrose

Answer

Maintains pH stability during storage

Answer

Prevents hemolysis in stored blood

Answer

Reduces metabolic activity in stored blood

Question 2

A middle-aged female presented with a 4cm mass in the upper outer quadrant of the breast. Biopsy showed densely packed cells within large extracellular spaces. Which of the following is the most likely diagnosis of this patient?

Accepted Answer

Colloid carcinoma of breast

Answer

Tubular carcinoma of breast

Answer

Medullary carcinoma of breast

Answer

Papillary carcinoma of breast

Question 3

Patient presented with diarrhoea, poor appetite and malabsorption. His duodenal biopsy was taken which showed crypt hyperplasia, villi atrophy and infiltration of CD8+ T cells in the epithelium. What is the likely diagnosis of the patient?

Accepted Answer

Celiac disease

Answer

Whipple disease

Answer

Environmental enteropathy

Answer

Pancreatitis

Question 4

A newborn baby presented with a failure to pass meconium in the immediate postnatal period. The pediatrician also notices visible yet ineffective peristalsis, and abdominal distention. A radiological contrast enema demonstrated a narrow conical segment and a dilated proximal bowel. A diagnosis of Hirschsprung disease was made. Which of the following is a cause of the condition in the patient?

Accepted Answer

Failure of migration of neural crest cells

Answer

Persistence of embryonic structures in the bowel wall

Answer

Congenital obstruction due to external factors

Answer

Abnormal peristalsis due to neural dysfunction

Question 5

Transplantation between identical twins-

Accepted Answer

Isograft

Answer

Xenograft

Answer

Autograft

Answer

Allograft

NEET-PG 2020 — Pathology