Neoplasia — MCQs
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A 45-year-old man is diagnosed with a nasopharyngeal tumor. Histologically, this neoplasm is composed of anaplastic cells immunoreactive for cytokeratin admixed with abundant lymphocytes. Which of the following factors is MOST likely implicated in the pathogenesis of this neoplasm?
All of the following are true regarding retinoblastoma, except:
Invasive squamous cell carcinoma is differentiated from carcinoma in situ by:
In a study comparing colonic polyps with malignant cells localized to the polyp versus those showing invasion of the stalk, molecular analysis revealed up-regulation of certain molecules in invasive malignant cells. Invasive lesions are more likely to exhibit lymphatic metastases. Which of the following markers is most likely to have increased expression in the invasive malignant epithelial cells?
CD-99 is a marker of which of the following neoplasms?
BRCA-1 gene is associated with which type of breast carcinoma?
An undifferentiated malignant tumor on immunohistochemical stain shows cytoplasmic positivity of most of the tumor cells for cytokeratin. What is the most probable diagnosis of the tumor?
A deep-seated carcinoma in the neck near the bifurcation of the common carotid artery, with no evidence of primary carcinoma of the mouth, pharynx, or larynx, is most likely what type of tumor?
Which is the most severe form of malignant melanoma?
Which of the following conditions is associated with an increase in LDH levels?
Neoplasia Indian Medical PG Practice Questions and MCQs
Question 61: A 45-year-old man is diagnosed with a nasopharyngeal tumor. Histologically, this neoplasm is composed of anaplastic cells immunoreactive for cytokeratin admixed with abundant lymphocytes. Which of the following factors is MOST likely implicated in the pathogenesis of this neoplasm?
- A. Cigarette smoking
- B. Epstein-Barr virus infection (Correct Answer)
- C. Ionizing radiation
- D. Overexpression of the bcl-2 gene
Explanation: ### Explanation **Correct Option: B. Epstein-Barr virus infection** The clinical presentation and histology described are classic for **Nasopharyngeal Carcinoma (NPC)**, specifically the undifferentiated type (WHO Type III) [4]. * **Pathogenesis:** EBV infects nasopharyngeal epithelial cells via the CD21 receptor (or through B-cell interaction) [1]. The viral genome expresses **LMP-1 (Latent Membrane Protein-1)**, which acts as an oncogene by mimicking CD40 signaling, activating NF-κB and JAK/STAT pathways, and preventing apoptosis by upregulating bcl-2 [3]. * **Histology:** It is characterized by "lymphoepithelioma-like" features—large, syncytial-appearing anaplastic epithelial cells (cytokeratin positive) surrounded by a dense reactive infiltrate of non-neoplastic T-lymphocytes [4]. **Why Other Options are Incorrect:** * **A. Cigarette smoking:** While a major risk factor for squamous cell carcinomas of the larynx and oropharynx, it has a much weaker association with the undifferentiated (EBV-related) type of NPC. * **C. Ionizing radiation:** This is a risk factor for thyroid cancers and sarcomas [2], but not typically linked to the primary pathogenesis of NPC. * **D. Overexpression of the bcl-2 gene:** While EBV’s LMP-1 does upregulate bcl-2 to prevent apoptosis, the *primary* inciting factor and the most specific association for this tumor type is the viral infection itself. **High-Yield Pearls for NEET-PG:** * **Bimodal Age Distribution:** NPC often shows peaks in adolescence and middle age (40-60 years). * **Geographic Distribution:** Highly prevalent in Southern China (Guangdong province) and parts of Africa [4]. * **Dietary Link:** Consumption of **nitrosamines** (salted fish) is a known co-factor [1]. * **Clinical Presentation:** Often presents late with a painless **cervical lymph node metastasis** or otitis media (due to Eustachian tube obstruction). * **Tumor Marker:** Serum levels of **IgA antibodies against EBV VCA** (Viral Capsid Antigen) are used for screening and monitoring recurrence [3]. **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. (Basic Pathology) introduces the student to key general principles of pathology, both as a medical science and as a clinical activity with a vital role in patient care. Part 2 (Disease Mechanisms) provides fundamental knowledge about the cellular and molecular processes involved in diseases, providing the rationale for their treatment. Part 3 (Systematic Pathology) deals in detail with specific diseases, with emphasis on the clinically important aspects., pp. 219-220. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. (Basic Pathology) introduces the student to key general principles of pathology, both as a medical science and as a clinical activity with a vital role in patient care. Part 2 (Disease Mechanisms) provides fundamental knowledge about the cellular and molecular processes involved in diseases, providing the rationale for their treatment. Part 3 (Systematic Pathology) deals in detail with specific diseases, with emphasis on the clinically important aspects., pp. 220-221. [3] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Neoplasia, pp. 335-336. [4] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Head and Neck, pp. 744-745.
Question 62: All of the following are true regarding retinoblastoma, except:
- A. Flexner-Wintersteiner rosettes
- B. Bilateral tumors are common in sporadic cases (Correct Answer)
- C. Rarely spreads to lungs
- D. Dystrophic calcification
Explanation: **Explanation:** Retinoblastoma is the most common intraocular tumor of childhood. Understanding the "Knudson Two-Hit Hypothesis" is crucial for solving this question [1]. **Why Option B is the correct answer (The Exception):** In **sporadic cases** (60% of cases), both mutations in the *RB1* gene occur somatically in a single retinal cell [1]. Because the probability of two spontaneous mutations occurring in both eyes is extremely low, sporadic retinoblastoma is almost always **unilateral and unifocal**. In contrast, **familial/hereditary cases** (40%) involve a germline mutation (the "first hit" is present in all cells); therefore, only one additional somatic mutation is needed, leading to tumors that are frequently **bilateral and multifocal** [1]. **Analysis of other options:** * **Option A (Flexner-Wintersteiner rosettes):** These are highly characteristic of retinoblastoma [2]. They consist of a ring of cuboidal cells surrounding a central lumen, representing photoreceptor differentiation [2]. * **Option C (Rarely spreads to lungs):** Retinoblastoma typically spreads via direct extension along the optic nerve to the CNS or via hematogenous spread to the **bone marrow and bones** [3]. Lung involvement is clinically rare compared to other pediatric tumors like Wilms tumor [3]. * **Option D (Dystrophic calcification):** This is a hallmark feature [2]. As the tumor outgrows its blood supply, necrosis occurs, leading to calcium deposition [2]. This is visible as "chalky white" areas on gross exam and is a key diagnostic finding on CT/Ultrasound. **High-Yield Clinical Pearls for NEET-PG:** * **Presentation:** Most common sign is **Leukocoria** (white pupillary reflex/Amaurotic cat’s eye). * **Genetics:** *RB1* gene is located on **Chromosome 13q14** [1]. * **Homer-Wright Rosettes:** Can also be seen (less specific; also found in Neuroblastoma/Medulloblastoma). * **Trilateral Retinoblastoma:** Bilateral retinoblastoma associated with a pinealoblastoma. * **Secondary Malignancy:** Patients with the hereditary form have a high risk of developing **Osteosarcoma** later in life. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Neoplasia, p. 300. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Eye, p. 1342. [3] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Manifestations Of Central And Peripheral Nervous System Disease, pp. 737-738.
Question 63: Invasive squamous cell carcinoma is differentiated from carcinoma in situ by:
- A. Penetration of basement membrane (Correct Answer)
- B. Number of mitotic figures
- C. Increased size of cell
- D. Nuclear pleomorphism
Explanation: ### Explanation The fundamental distinction between **Carcinoma in Situ (CIS)** and **Invasive Carcinoma** lies in the integrity of the **basement membrane** [1]. **1. Why Option A is correct:** Carcinoma in situ represents a full-thickness dysplasia of the epithelium where the cells exhibit all the cytological features of malignancy (pleomorphism, high N:C ratio, frequent mitoses). However, these cells remain confined by the basement membrane [1]. Once the malignant cells secrete proteases (like Type IV collagenases/metalloproteinases) and **penetrate the basement membrane** to invade the underlying stroma, the lesion is classified as **Invasive Squamous Cell Carcinoma** [2]. This transition is the critical step that grants the tumor access to blood vessels and lymphatics, enabling metastasis [1]. **2. Why the other options are incorrect:** * **Options B, C, and D (Mitotic figures, Increased cell size, Nuclear pleomorphism):** These are all features of **dysplasia** and cellular atypia. While they are present in invasive carcinoma, they are also characteristically present in carcinoma in situ [1]. Therefore, they cannot be used to differentiate between the two stages; they only indicate that the tissue is neoplastic rather than normal. ### NEET-PG High-Yield Pearls: * **Dysplasia vs. CIS:** Dysplasia is graded as mild, moderate, or severe. When the entire thickness of the epithelium is involved but the basement membrane is intact, it is called **Carcinoma in Situ** [1]. * **Metastatic Potential:** CIS has **zero** risk of metastasis because the epithelium is avascular. Metastasis only becomes possible after basement membrane penetration [1]. * **Key Enzyme:** **Metalloproteinases (MMPs)**, specifically MMP-2 and MMP-9, are high-yield enzymes responsible for degrading Type IV collagen in the basement membrane during invasion [3]. **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. (Basic Pathology) introduces the student to key general principles of pathology, both as a medical science and as a clinical activity with a vital role in patient care. Part 2 (Disease Mechanisms) provides fundamental knowledge about the cellular and molecular processes involved in diseases, providing the rationale for their treatment. Part 3 (Systematic Pathology) deals in detail with specific diseases, with emphasis on the clinically important aspects., pp. 209-210. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Neoplasia, pp. 314-315. [3] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. (Basic Pathology) introduces the student to key general principles of pathology, both as a medical science and as a clinical activity with a vital role in patient care. Part 2 (Disease Mechanisms) provides fundamental knowledge about the cellular and molecular processes involved in diseases, providing the rationale for their treatment. Part 3 (Systematic Pathology) deals in detail with specific diseases, with emphasis on the clinically important aspects., pp. 232-233.
Question 64: In a study comparing colonic polyps with malignant cells localized to the polyp versus those showing invasion of the stalk, molecular analysis revealed up-regulation of certain molecules in invasive malignant cells. Invasive lesions are more likely to exhibit lymphatic metastases. Which of the following markers is most likely to have increased expression in the invasive malignant epithelial cells?
- A. BCL2
- B. CD44 (Correct Answer)
- C. EGFR
- D. RAS
Explanation: **Explanation:** The correct answer is **CD44**. **Why CD44 is correct:** CD44 is a cell surface adhesion molecule that normally binds to hyaluronate in the extracellular matrix. In the context of neoplasia, specific isoforms of CD44 (especially CD44v6) are strongly associated with **tumor progression and metastasis**. Increased expression of CD44 on malignant epithelial cells enhances their ability to migrate through the stroma and enter lymphatic channels [1]. It is often used as a marker for "cancer stem cells" in colonic tumors, signifying a higher potential for invasion and distant spread. **Why other options are incorrect:** * **BCL2:** This is an anti-apoptotic protein. While its overexpression (common in follicular lymphoma) prevents programmed cell death, it is not a primary driver of basement membrane invasion or lymphatic metastasis. * **EGFR:** The Epidermal Growth Factor Receptor is a tyrosine kinase receptor involved in cell proliferation signaling. While it is a target for therapy (e.g., Cetuximab), its upregulation alone is less specific for the transition from *in situ* to *invasive* disease compared to adhesion molecules like CD44. * **RAS:** Mutations in the RAS oncogene (specifically KRAS in colon cancer) occur early in the adenoma-carcinoma sequence (the "adenoma" phase). While it promotes uncontrolled growth, it does not specifically mediate the physical process of invasion into the stalk or lymphatics. **NEET-PG High-Yield Pearls:** * **CD44 Function:** Mediates cell-matrix interactions; its splice variants are key markers for metastatic potential [1]. * **Vogelstein Model (Colon Cancer):** Remember the sequence: *APC* loss (initial mutation) → *KRAS* mutation (adenoma) → *TP53* loss and *SMAD4* (carcinoma). * **Invasion Marker:** The hallmark of malignancy in a colonic polyp is the penetration of malignant cells through the **muscularis mucosae** into the submucosa of the stalk [2]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Neoplasia, pp. 314-315. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Gastrointestinal Tract, pp. 815-817.
Question 65: CD-99 is a marker of which of the following neoplasms?
- A. Ewing sarcoma (Correct Answer)
- B. Chronic lymphocytic leukemia
- C. Mantle cell lymphoma
- D. All of the above
Explanation: **Explanation:** **CD99 (MIC2 gene product)** is a 32-kDa transmembrane glycoprotein that is highly sensitive for the **Ewing Sarcoma/Primitive Neuroectodermal Tumor (PNET)** family of tumors. In Ewing sarcoma, CD99 typically shows a characteristic **strong, diffuse, and membranous** staining pattern. While not entirely specific, it is the primary diagnostic immunohistochemical marker used to differentiate Ewing sarcoma from other "small round blue cell tumors" of childhood [1]. **Analysis of Options:** * **A. Ewing Sarcoma (Correct):** As mentioned, CD99 is the hallmark marker. It is encoded by the *MIC2* gene located on the pseudoautosomal region of the X and Y chromosomes. * **B. Chronic Lymphocytic Leukemia (CLL):** CLL is characterized by the expression of **CD5, CD19, CD20, and CD23**. CD99 is not a diagnostic marker for mature B-cell neoplasms like CLL. * **C. Mantle Cell Lymphoma (MCL):** MCL is defined by the translocation t(11;14) leading to **Cyclin D1** overexpression [2]. It also expresses **CD5 and SOX11**, but not CD99 [2]. **High-Yield Clinical Pearls for NEET-PG:** * **Genetics of Ewing Sarcoma:** Most common translocation is **t(11;22)(q24;q12)**, resulting in the **EWS-FLI1** fusion gene. * **Morphology:** Characterized by "Small Round Blue Cells" with scant cytoplasm containing glycogen (PAS positive). * **Radiology:** Classic **"Onion-skin"** periosteal reaction. * **Differential Diagnosis:** Other CD99-positive tumors include Lymphoblastic Lymphoma, Synovial Sarcoma, and Solitary Fibrous Tumor; however, in the context of bone tumors, Ewing sarcoma is the primary association. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Bones, Joints, and Soft Tissue Tumors, pp. 1204-1205. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Diseases of White Blood Cells, Lymph Nodes, Spleen, and Thymus, pp. 610-612.
Question 66: BRCA-1 gene is associated with which type of breast carcinoma?
- A. Lobular carcinoma
- B. Mucinous carcinoma (Correct Answer)
- C. Tubular carcinoma
- D. Papillary carcinoma
Explanation: **Explanation:** The **BRCA-1 gene**, located on chromosome 17q21, is a tumor suppressor gene involved in DNA repair via homologous recombination. While BRCA-1 is most famously associated with **Medullary Carcinoma** (a subtype of invasive ductal carcinoma characterized by a lymphoid stroma and triple-negative status) [1], it also shows a significant association with **Mucinous (Colloid) Carcinoma**. [2] In the context of this specific question, Mucinous carcinoma is the correct choice as it is a recognized phenotype in BRCA-1 mutation carriers. These tumors are characterized by clusters of tumor cells floating in large pools of extracellular mucin. [2] **Analysis of Options:** * **Mucinous Carcinoma (Correct):** Studies have shown that hereditary breast cancers, particularly those linked to BRCA-1, frequently exhibit specific "special types" of morphology, including medullary and mucinous features. [2] * **Lobular Carcinoma:** This is more commonly associated with the loss of **E-cadherin** expression (CDH1 gene mutation) [2]. While it can occur in BRCA carriers, it is not the classic association for BRCA-1. * **Tubular Carcinoma:** This is a well-differentiated slow-growing tumor typically associated with a very favorable prognosis and is usually sporadic, not specifically linked to BRCA-1. * **Papillary Carcinoma:** This is a rare subtype of invasive ductal carcinoma that does not have a primary genetic link to the BRCA-1 mutation. **NEET-PG High-Yield Pearls:** * **BRCA-1:** Associated with Breast (often Triple Negative/Medullary), Ovarian (Serous Cystadenocarcinoma), and Fallopian tube cancers. [2] * **BRCA-2:** Located on chromosome 13q12; associated with **Male Breast Cancer**, Prostate, and Pancreatic cancer. [2] * **Li-Fraumeni Syndrome:** Germline mutation of **TP53**; associated with early-onset breast cancer, sarcomas, and leukemia. * **Cowden Syndrome:** Mutation of **PTEN**; associated with breast cancer and thyroid (follicular) cancer. **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Liver And Biliary System Disease, pp. 455-456. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Breast, pp. 1058-1069.
Question 67: An undifferentiated malignant tumor on immunohistochemical stain shows cytoplasmic positivity of most of the tumor cells for cytokeratin. What is the most probable diagnosis of the tumor?
- A. Carcinoma (Correct Answer)
- B. Lymphoma
- C. Sarcoma
- D. Malignant melanoma
Explanation: **Explanation:** The core concept tested here is the use of **Immunohistochemistry (IHC)** markers to determine the lineage of an undifferentiated tumor. IHC markers are specific proteins (antigens) expressed by different cell types [2]. **Why Carcinoma is correct:** **Cytokeratins (CK)** are intermediate filaments found in the intracytoplasmic cytoskeleton of **epithelial cells**. Since carcinomas are malignant tumors of epithelial origin, they characteristically show cytoplasmic positivity for cytokeratin [1]. This is the most reliable marker to distinguish a carcinoma from other "round cell" or undifferentiated tumors. **Why the other options are incorrect:** * **Lymphoma:** These are tumors of lymphoid lineage. The primary screening marker is **LCA (Leukocyte Common Antigen)** or CD45 [1]. * **Sarcoma:** These are tumors of mesenchymal origin (connective tissue). The most common screening marker is **Vimentin**. * **Malignant Melanoma:** These tumors arise from melanocytes. Key markers include **S-100** (most sensitive), **HMB-45**, and **Melan-A** (more specific) [3]. **High-Yield Clinical Pearls for NEET-PG:** * **Vimentin** is the "universal" marker for mesenchymal cells but can be co-expressed in some carcinomas (e.g., Renal Cell Carcinoma). * **Desmin** is the specific marker for myogenic (muscle) tumors like Rhabdomyosarcoma [4]. * **Synaptophysin and Chromogranin** are markers for Neuroendocrine tumors. * If a tumor is **CK negative and Vimentin positive**, think Sarcoma or Melanoma. * If a tumor is **CK positive and Vimentin negative**, think Carcinoma. **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. (Basic Pathology) introduces the student to key general principles of pathology, both as a medical science and as a clinical activity with a vital role in patient care. Part 2 (Disease Mechanisms) provides fundamental knowledge about the cellular and molecular processes involved in diseases, providing the rationale for their treatment. Part 3 (Systematic Pathology) deals in detail with specific diseases, with emphasis on the clinically important aspects., pp. 208-209. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Neoplasia, pp. 341-342. [3] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. (Basic Pathology) introduces the student to key general principles of pathology, both as a medical science and as a clinical activity with a vital role in patient care. Part 2 (Disease Mechanisms) provides fundamental knowledge about the cellular and molecular processes involved in diseases, providing the rationale for their treatment. Part 3 (Systematic Pathology) deals in detail with specific diseases, with emphasis on the clinically important aspects., pp. 258-259. [4] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Bones, Joints, and Soft Tissue Tumors, pp. 1224-1235.
Question 68: A deep-seated carcinoma in the neck near the bifurcation of the common carotid artery, with no evidence of primary carcinoma of the mouth, pharynx, or larynx, is most likely what type of tumor?
- A. Collar stud abscess.
- B. Branchiogenic carcinoma. (Correct Answer)
- C. Subhyoid bursal cyst.
- D. Cold abscess.
Explanation: **Explanation:** The clinical presentation describes a deep-seated carcinoma located at the **bifurcation of the common carotid artery** (the typical anatomical site of the second branchial cleft) without a detectable primary source in the upper aerodigestive tract. This is the classic definition of a **Branchiogenic Carcinoma**. 1. **Why it is correct:** Branchiogenic carcinoma is a rare malignancy arising from the epithelial remnants of the **branchial clefts** (specifically the second cleft). According to **Martin’s criteria**, for a diagnosis to be made, the tumor must occur along the line of branchial remnants, its histological appearance must be consistent with vestigial remnants, and most importantly, a thorough search must rule out any other primary source (like the tonsils or nasopharynx). 2. **Why other options are incorrect:** * **Collar stud abscess:** This is a clinical presentation of tuberculous cervical lymphadenitis where a superficial abscess communicates with a deeper lymph node through a small opening in the fascia. It is inflammatory/infectious, not neoplastic. * **Subhyoid bursal cyst:** This is a midline cystic swelling located between the hyoid bone and the thyroid cartilage. It is benign and does not present as a deep-seated carcinoma. * **Cold abscess:** Typically associated with spinal tuberculosis (Pott’s disease), it presents as a fluctuant, non-tender swelling without classical signs of inflammation. It is not a malignant process. **Clinical Pearls for NEET-PG:** * **Location:** The most common site for branchial cysts/carcinomas is the **upper third of the neck**, anterior to the sternocleidomastoid muscle at the level of the carotid bifurcation [1]. * **Rule of Thumb:** In an elderly patient presenting with a "branchiogenic carcinoma," always perform a pan-endoscopy and PET scan first, as most are actually **metastatic squamous cell carcinomas** from an occult primary in the oropharynx (e.g., base of tongue or palatine tonsil). **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Head and Neck, pp. 748-749.
Question 69: Which is the most severe form of malignant melanoma?
- A. Superficially spreading melanoma
- B. Nodular infiltrating type melanoma (Correct Answer)
- C. Melanoma arising in lower limb
- D. Melanoma arising in choroid
Explanation: **Explanation:** The severity and prognosis of malignant melanoma are primarily determined by the **growth phase**. [1] **1. Why Nodular Melanoma is the most severe:** Unlike other types, **Nodular Melanoma (NM)** lacks an initial radial growth phase. It begins almost immediately with a **vertical growth phase**, characterized by downward invasion into the dermis [1]. This rapid deep penetration increases the risk of lymphatic and hematogenous metastasis early in the disease [2]. According to **Breslow’s Depth**, deeper lesions have a significantly poorer prognosis, making NM the most aggressive clinical subtype [1]. **2. Analysis of Incorrect Options:** * **Superficially Spreading Melanoma (SSM):** This is the most common type overall. It has a prolonged **radial growth phase** (horizontal spread) before entering the vertical phase, allowing for earlier detection and a better prognosis than the nodular type [1]. * **Melanoma arising in lower limb:** While the site can influence drainage, the anatomical location is not an independent marker of "severity" compared to the histological subtype and depth of invasion. * **Melanoma arising in choroid:** Uveal melanomas have a unique metastatic pathway (primarily hematogenous to the liver), but they are generally less aggressive in terms of rapid systemic spread compared to the nodular cutaneous variant. **High-Yield Clinical Pearls for NEET-PG:** * **Most common type:** Superficially Spreading Melanoma. * **Best prognosis:** Lentigo Maligna Melanoma (remains in radial phase for years). * **Most important prognostic factor:** **Breslow’s Thickness** (measured from the granular layer of the epidermis to the deepest tumor cell) [2]. * **ABCDE Criteria:** Asymmetry, Border irregularity, Color variegation, Diameter (>6mm), and Evolution. * **Common Mutation:** **BRAF V600E** is seen in ~50% of cases (Target for Vemurafenib) [2]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Skin, pp. 1151-1152. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Disorders Involving Inflammatory And Haemopoietic Cells, pp. 650-651.
Question 70: Which of the following conditions is associated with an increase in LDH levels?
- A. Bulky disease (Correct Answer)
- B. Lymphoma
- C. Liver metastasis
- D. Lung metastasis
Explanation: **Explanation:** **Lactate Dehydrogenase (LDH)** is a cytoplasmic enzyme present in almost all body tissues. It is released into the bloodstream following cell damage or death. In the context of oncology, LDH serves as a non-specific marker of **cell turnover** and metabolic activity. **Why "Bulky Disease" is the best answer:** "Bulky disease" refers to a large tumor mass (typically >7–10 cm in diameter). Large tumors have high rates of cell proliferation and a significant proportion of internal necrosis due to outgrowing their blood supply. This massive cell turnover and necrosis lead to a substantial release of LDH into the circulation [1]. In clinical practice, LDH levels are used as a surrogate marker for **tumor burden** and are a key prognostic factor in the International Prognostic Index (IPI). **Analysis of other options:** * **Lymphoma:** While LDH is elevated in many lymphomas (especially high-grade ones like DLBCL or Burkitt’s), it is specifically the *bulk* of the lymphoma that dictates the degree of LDH elevation [1]. * **Liver/Lung Metastasis:** While metastases can raise LDH, the elevation is usually due to the volume of the metastatic deposits (bulk) rather than the location itself. "Bulky disease" is the more encompassing physiological term for the mechanism of LDH elevation. **High-Yield Clinical Pearls for NEET-PG:** * **Tumor Lysis Syndrome (TLS):** LDH is a critical marker for monitoring TLS risk; high LDH indicates high cell turnover. * **Germ Cell Tumors:** LDH is a specific serum marker for **Dysgerminoma** (Ovary) and **Seminoma** (Testis). * **Ewing Sarcoma:** Elevated LDH at diagnosis is a poor prognostic indicator. * **Other causes of high LDH:** Megaloblastic anemia (highest levels), Hemolysis, and Myocardial Infarction. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Diseases of White Blood Cells, Lymph Nodes, Spleen, and Thymus, pp. 606, 612-613.
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