Which layer of the epidermis is primarily involved in spongiosis?
What does a Tzanck smear in varicella-zoster virus infection typically show?
Lendrum's stain is done for:
Virchow method of organ removal is:
NEET-PG 2013 - Pathology NEET-PG Practice Questions and MCQs
Question 71: Which layer of the epidermis is primarily involved in spongiosis?
- A. Stratum basale
- B. Stratum corneum
- C. Stratum granulosum
- D. Stratum spinosum (Correct Answer)
Explanation: ***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.
Question 72: What does a Tzanck smear in varicella-zoster virus infection typically show?
- A. Acantholytic cells
- B. Epidermal spongiosis
- C. Multinucleated giant cells (Correct Answer)
- D. Necrotic cells
Explanation: ***Multinucleated giant cells*** - A Tzanck smear identifies **multinucleated giant cells** with intranuclear inclusions, which are characteristic **cytopathic effects** of herpesviruses like VZV [1]. - These cells result from the fusion of infected keratinocytes, a hallmark finding in **herpes simplex** and **varicella-zoster infections** [1]. *Acantholytic cells* - Acantholytic cells are seen in conditions like **pemphigus vulgaris**, where there is loss of cell-to-cell adhesion between keratinocytes, leading to intraepidermal blistering. - While VZV can cause blistering, the primary cytological finding on Tzanck smear is not acantholysis but rather the presence of multinucleated cells. *Epidermal spongiosis* - Spongiosis refers to **intercellular edema** of epidermal cells, leading to widening of the intercellular spaces, typically seen in **eczematous dermatoses** [1]. - This finding is not specific to viral infections and does not represent the characteristic cytopathic effect of VZV on a Tzanck smear. *Necrotic cells* - Necrotic cells, or dead cells, are a general finding in many inflammatory and infectious processes where tissue damage occurs. - While VZV infection can lead to cell necrosis, the presence of isolated necrotic cells is not the specific, diagnostic feature for VZV on a Tzanck smear. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Infectious Diseases, pp. 366-367.
Question 73: Lendrum's stain is done for:
- A. Air embolism
- B. Pulmonary embolism
- C. Fat embolism
- D. Amniotic fluid embolism (Correct Answer)
Explanation: ***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.
Question 74: Virchow method of organ removal is:
- A. In situ dissection
- B. Organs removed en masse
- C. Organs removed en bloc
- D. Organs removed one by one (Correct Answer)
Explanation: ***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.