Neoplasia Practice Questions

Q: CD-99 is a marker of which of the following neoplasms?

Ewing sarcoma. **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.

Q: Which of the following conditions is associated with an increase in LDH levels?

Bulky disease. **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.

Question 1

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?

Accepted Answer

Epstein-Barr virus infection

Answer

Cigarette smoking

Answer

Ionizing radiation

Answer

Overexpression of the bcl-2 gene

Question 2

All of the following are true regarding retinoblastoma, except:

Accepted Answer

Bilateral tumors are common in sporadic cases

Answer

Flexner-Wintersteiner rosettes

Answer

Rarely spreads to lungs

Answer

Dystrophic calcification

Question 3

Invasive squamous cell carcinoma is differentiated from carcinoma in situ by:

Accepted Answer

Penetration of basement membrane

Answer

Number of mitotic figures

Answer

Increased size of cell

Answer

Nuclear pleomorphism

Question 4

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?

Accepted Answer

CD44

Answer

BCL2

Answer

EGFR

Answer

RAS

Question 5

CD-99 is a marker of which of the following neoplasms?

Accepted Answer

Ewing sarcoma

Answer

Chronic lymphocytic leukemia

Answer

Mantle cell lymphoma

Answer

All of the above

Question 6

BRCA-1 gene is associated with which type of breast carcinoma?

Accepted Answer

Mucinous carcinoma

Answer

Lobular carcinoma

Answer

Tubular carcinoma

Answer

Papillary carcinoma

Question 7

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?

Accepted Answer

Carcinoma

Answer

Lymphoma

Answer

Sarcoma

Answer

Malignant melanoma

Question 8

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?

Accepted Answer

Branchiogenic carcinoma.

Answer

Collar stud abscess.

Answer

Subhyoid bursal cyst.

Answer

Cold abscess.

Question 9

Which is the most severe form of malignant melanoma?

Accepted Answer

Nodular infiltrating type melanoma

Answer

Superficially spreading melanoma

Answer

Melanoma arising in lower limb

Answer

Melanoma arising in choroid

Question 10

Which of the following conditions is associated with an increase in LDH levels?

Accepted Answer

Bulky disease

Answer

Lymphoma

Answer

Liver metastasis

Answer

Lung metastasis

Neoplasia — MCQs

Neoplasia — MCQs

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