NEET-PG 2013 - Pathology Practice Questions

Q: What is the most common malignant tumor of the skeletal system?

Metastasis. ***Metastasis*** - **Skeletal metastasis** is overwhelmingly the most common malignant tumor involving bone, as many primary cancers (e.g., breast, prostate, lung) frequently spread to bone [1]. - While not originating in the bone, these metastatic deposits are malignant neoplasms within the skeletal system, making them the most prevalent. *Multiple myeloma* - This is a **primary malignancy of plasma cells** that arises in the bone marrow, causing destructive bone lesions. - It is the most common **primary malignant bone tumor** in adults, but still less common than metastatic disease. *Osteosarcoma* - This is the most common **primary malignant bone tumor** in **children and adolescents**, primarily affecting long bones [2]. - While a significant primary bone cancer, its incidence is lower than that of metastatic bone disease across all age groups [1]. *Chondrosarcoma* - This is a malignant tumor of **cartilage-forming cells** and is the second most common primary bone cancer in adults, after multiple myeloma [3]. - It is much less common than metastatic disease and osteosarcoma [1], [3]. **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Osteoarticular And Connective Tissue Disease, pp. 671-672. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Bones, Joints, and Soft Tissue Tumors, p. 1202. [3] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Bones, Joints, and Soft Tissue Tumors, p. 1204.

Q: Which layer of the epidermis is primarily involved in spongiosis?

Stratum spinosum. ***Stratum spinosum*** - **Spongiosis** is characterized by **intercellular edema** (fluid accumulation between cells) within the epidermis [1], primarily affecting the **stratum spinosum** [2]. - The cells of the stratum spinosum, known as **keratinocytes**, become separated by this edema, giving the tissue a "spongy" appearance on histology due to the preservation of **desmosomal attachments**. *Stratum basale* - The **stratum basale** is the deepest layer of the epidermis, responsible for **cell proliferation** and attachment to the basement membrane. - While edema can affect all epidermal layers in severe cases, spongiosis specifically refers to the intercellular edema most prominent in the stratum spinosum [2]. *Stratum corneum* - The **stratum corneum** is the outermost layer of the epidermis, composed of dead, flattened **keratinocytes** that provide a protective barrier. - Edema in this layer is less common and would not be described as spongiosis, which implies living cells with preserved intercellular junctions. *Stratum granulosum* - The **stratum granulosum** lies above the stratum spinosum and is characterized by cells containing **keratohyalin granules**. - While it can be affected by intercellular edema, the most pronounced and characteristic spongiosis occurs in the stratum spinosum where cells are still actively synthesizing keratin and have strong desmosomal connections [2]. **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Disorders Involving Inflammatory And Haemopoietic Cells, p. 636. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Skin, p. 1166.

Q: Lendrum's stain is done for:

Amniotic fluid embolism. ***Amniotic fluid embolism*** - **Lendrum's stain** (MSB - Martius Scarlet Blue) is specifically used to identify **fibrin**, **mucin**, and **squamous cells** in the pulmonary vasculature, which are characteristic findings in amniotic fluid embolism. [1] - This stain excellently demonstrates **fibrin** (stains red) and helps visualize components of amniotic fluid that embolize to the mother's lungs, leading to a severe, often fatal, obstetric emergency. [1] - Lendrum's method is particularly valuable in forensic pathology and autopsy diagnosis of this condition. *Air embolism* - Air embolism diagnosis relies on identifying **air bubbles** in the cardiovascular system, often confirmed by imaging studies or direct visualization during autopsy. [1] - Special stains are not typically used for direct detection of air in tissue sections. *Pulmonary embolism* - Pulmonary embolism, typically caused by a **blood clot**, is diagnosed by identifying **fibrin** and **red blood cells** within pulmonary arteries, often with stains like hematoxylin and eosin (H&E). [1] - While Lendrum's stain can demonstrate fibrin, it is specifically employed when amniotic fluid embolism is suspected, not for routine thromboembolic disease. *Fat embolism* - **Fat embolism** is diagnosed by demonstrating **fat globules** in the pulmonary microvasculature using **fat stains** like **Oil Red O** or **Sudan Black**, usually on frozen sections. - Lendrum's stain does not specifically highlight fat emboli. **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Respiratory Tract Disease, pp. 322-324.

Q: Virchow method of organ removal is:

Organs removed one by one. ***Organs removed one by one*** - The **Virchow method** is characterized by the sequential removal of **individual organs** through a systematic dissection. - This technique allows for detailed inspection and measurement of each organ independently, which can be useful for identifying specific pathologies confined to single structures. *In situ dissection* - This method involves dissecting and examining organs **within the body cavity before removal**, which is not the primary characteristic of the Virchow method. - While some dissection occurs *in situ*, the essential principle of Virchow's method is the **separate extraction** of organs. *Organs removed en masse* - This describes the **Ghon method**, where organs are removed in three blocks (thoracic, abdominal-gastrointestinal, and genitourinary) and then dissected. - This method aims to preserve anatomical relationships between organs, which contrasts with the single-organ focus of the Virchow method. *Organs removed en bloc* - This term generally refers to removing organs in **several blocks or groups** (similar to the Ghon method), maintaining some anatomical connections. - It does not involve the individual removal of each organ, which is the defining feature of the Virchow technique.

Question 1

What is the most common malignant tumor of the skeletal system?

Accepted Answer

Metastasis

Answer

Chondrosarcoma

Answer

Multiple myeloma

Answer

Osteosarcoma

Question 2

Which layer of the epidermis is primarily involved in spongiosis?

Accepted Answer

Stratum spinosum

Answer

Stratum basale

Answer

Stratum corneum

Answer

Stratum granulosum

Question 3

Lendrum's stain is done for:

Accepted Answer

Amniotic fluid embolism

Answer

Air embolism

Answer

Pulmonary embolism

Answer

Fat embolism

Question 4

Virchow method of organ removal is:

Accepted Answer

Organs removed one by one

Answer

In situ dissection

Answer

Organs removed en masse

Answer

Organs removed en bloc

NEET-PG 2013 — Pathology