Neoplasia Practice Questions

Q: Which histological feature characterizes an adenomatoid odontogenic tumour?

Tubular or duct-like cells. **Adenomatoid Odontogenic Tumour (AOT)**, often referred to as the "Two-Thirds Tumor," is a benign odontogenic neoplasm. The hallmark histological feature of AOT is the presence of **tubular or duct-like structures** (Option B). These structures are formed by cuboidal or columnar epithelial cells arranged in a circular pattern, with nuclei polarized away from the central lumen. This lumen often contains eosinophilic material or pre-dentin. It is important to note that these are not true glandular ducts but rather a specific pattern of odontogenic epithelium. **Analysis of Incorrect Options:** * **Option A (Polyhedral epithelial cells):** These are characteristic of **Pindborg Tumors** (Calcifying Epithelial Odontogenic Tumor), which feature sheets of polyhedral cells with distinct intercellular bridges and amyloid-like deposits. * **Option C (Stellate shaped cells):** Stellate reticulum-like cells are the classic feature of **Ameloblastoma**. While AOT can have spindle cells, the "star-shaped" arrangement is specific to the central portion of Ameloblastoma follicles. * **Option D (Stratified squamous epithelial cells):** These are found in **Squamous Odontogenic Tumors** or odontogenic cysts (like Keratocystic Odontogenic Tumors), but are not a defining feature of AOT. **NEET-PG High-Yield Pearls:** * **The "Two-Thirds" Rule:** 2/3rd occur in the **maxilla**, 2/3rd in **young females** (teens), and 2/3rd are associated with an **impacted canine** [1]. * **Radiology:** Appears as a well-defined radiolucency surrounding an unerupted tooth (follicular type), often containing "snowflake" calcifications. * **Treatment:** Conservative enucleation; recurrence is extremely rare. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Head and Neck, p. 741.

Q: Proliferation of cells which are not native to that place is known as:

Both B and C. **Explanation:** The core concept tested here is the distinction between developmental malformations involving tissue displacement versus those involving local overgrowth. **1. Why the Correct Answer is D (Both B and C):** * **Choriostoma (Heterotopia):** This refers to a mass of histologically normal tissue present in an **abnormal anatomical location** (e.g., a nodule of well-developed pancreatic tissue in the submucosa of the stomach). The cells are "not native" to the site. * **Fordyce’s Granules:** These are ectopic sebaceous glands found on the oral mucosa or vermilion border of the lips. Since sebaceous glands are normally associated with hair follicles of the skin and are not native to the oral mucosa, they represent a specific clinical example of a **choriostoma**. **2. Why Option A is Incorrect:** * **Hamartoma:** This is a focal overgrowth of cells and tissues **native** to the organ in which it occurs (e.g., a pulmonary hamartoma containing cartilage, bronchial epithelium, and connective tissue). While the architecture is disorganized, the cellular elements belong to that specific site. **3. High-Yield NEET-PG Pearls:** * **Hamartoma vs. Choriostoma:** Remember "H" for **H**amartoma = **H**ome (native tissue); "C" for **C**horiostoma = **C**hanged location (non-native). * **Common Choriostomas:** Pancreatic tissue in the gallbladder/duodenum; Gastric mucosa in Meckel’s diverticulum. * **Common Hamartomas:** Lungs (most common site), Bile duct hamartomas (Von Meyenburg complexes), and Cowden Syndrome (multiple hamartomas). * **Neoplasia:** Unlike true neoplasms, both hamartomas and choriostomas are developmental anomalies and typically show coordinated growth with the host.

Q: A patient presents with bilateral proptosis. Biopsy from the orbital region shows spindle cells arranged in compact fascicles with nuclear palisading forming Verocay bodies (Antoni A pattern), alternating with loose hypocellular myxoid areas (Antoni B pattern). Immunohistochemistry shows strong S-100 positivity. What is the most likely diagnosis?

Schwannoma. ***Schwannoma*** - Bilateral proptosis with **Antoni A and B patterns** and **Verocay bodies** on biopsy are pathognomonic for schwannoma, particularly in the orbital region. - **S-100 positive** staining confirms neural origin, and orbital schwannomas commonly present with gradual **proptosis** and visual disturbances. *Leiomyoma* - Shows **smooth muscle differentiation** with spindle cells arranged in fascicles, positive for **smooth muscle actin (SMA)**. - Lacks the characteristic **Antoni patterns** and **Verocay bodies** seen in neural tumors like schwannoma. *Rhabdomyosarcoma* - Most common **primary orbital malignancy** in children, showing **cross-striations** and positive **desmin** staining. - Presents with **rapid onset proptosis** and is highly aggressive, unlike the benign nature suggested by typical schwannoma biopsy findings. *Fibromatosis* - Characterized by **proliferating fibroblasts** in a collagenous stroma without the **biphasic Antoni A/B pattern**. - Shows **beta-catenin positivity** and lacks **S-100 expression** and **Verocay bodies** diagnostic of schwannoma.

Q: Which of the following does NOT show antitumor activity?

Basophils. **Explanation:** The immune system employs a mechanism known as **immunosurveillance** to identify and eliminate nascent tumor cells. This process primarily involves cell-mediated immunity. **Why Basophils are the Correct Answer:** Basophils are granulocytes primarily involved in **Type I hypersensitivity reactions** (allergic responses) and defense against helminthic parasites. They circulate in the blood and release mediators like histamine and heparin upon activation. Unlike other leukocytes, basophils do **not** possess direct tumoricidal activity or the ability to recognize tumor-associated antigens. **Analysis of Incorrect Options:** * **Cytotoxic T Lymphocytes (CTLs/CD8+):** These are the primary effectors of antitumor immunity. They recognize tumor-specific antigens presented on MHC Class I molecules and induce apoptosis via perforins and granzymes. * **Natural Killer (NK) Cells:** These are the "first line of defense" against tumors. They are particularly effective against tumor cells that attempt to evade CTLs by downregulating MHC Class I expression (the "missing self" hypothesis). * **Macrophages:** Activated macrophages (specifically the M1 phenotype) can kill tumor cells by releasing Reactive Oxygen Species (ROS), Nitric Oxide (NO), and Tumor Necrosis Factor (TNF-α). They also act as professional antigen-presenting cells to prime T-cell responses. **NEET-PG High-Yield Pearls:** * **Most potent killer of tumor cells:** Cytotoxic T Lymphocytes (CD8+). * **Cytokine with maximum antitumor activity:** Interferon-gamma (IFN-γ) and TNF-α. * **M1 vs. M2 Macrophages:** M1 macrophages are **antitumor** (pro-inflammatory), while M2 macrophages (Tumor-Associated Macrophages) can actually **promote** tumor growth and angiogenesis. * **LAK Cells:** Lymphokine-activated killer cells (NK cells treated with IL-2) are used in experimental immunotherapy.

Q: Which of the following does not describe a documented mechanism of tumor-mediated immune evasion?

Antigenic variation. **Explanation:** The correct answer is **Antigenic variation**. While common in pathogens (like *Trypanosoma* or Influenza), antigenic variation is not a primary mechanism for tumor evasion. Tumors typically evade the immune system by suppressing the response or hiding their identity, rather than rapidly changing their surface proteins to stay ahead of antibodies. **Why the other options are documented mechanisms:** * **Downregulation of Class I MHC:** Tumors often stop expressing MHC-I molecules. Since CD8+ T-cells require MHC-I to recognize "non-self" tumor antigens, this makes the tumor "invisible" to cytotoxic T-lymphocytes. * **Secretion of TGF-β:** Tumors create an immunosuppressive microenvironment by secreting cytokines like **TGF-β** and **IL-10**. These inhibit T-cell activation and promote the recruitment of Regulatory T-cells (Tregs), which dampen the immune response. * **Secretion of Decoy Molecules:** Some tumors shed their surface antigens as soluble "decoy" molecules. These bind to circulating antibodies or T-cell receptors before they can reach the actual tumor cell, effectively neutralizing the immune attack. **High-Yield Clinical Pearls for NEET-PG:** * **Immune Checkpoints:** Tumors often upregulate **PD-L1**, which binds to PD-1 on T-cells, sending an inhibitory signal that "shuts down" the T-cell (T-cell exhaustion). * **Fas Ligand (FasL):** Some tumors express FasL to induce apoptosis (programmed cell death) in infiltrating T-cells that attempt to attack them. * **NK Cells:** While MHC-I downregulation helps evade T-cells, it theoretically makes tumors vulnerable to **Natural Killer (NK) cells**, which follow the "missing self" hypothesis. However, tumors often evolve additional mechanisms to inhibit NK cell receptors.

Question 1

A 2-year-old boy is found to have bilateral retinal tumors. Molecular studies demonstrate a germline mutation in one allele of the Rb gene. Which of the following genetic events best explains the mechanism of carcinogenesis in this patient?

Accepted Answer

Loss of heterozygosity

Answer

Balanced translocation

Answer

Expansion of trinucleotide repeat

Answer

Gene amplification

Question 2

Her2 neu receptor is used in breast carcinoma for what purpose?

Accepted Answer

Predicting response to treatment

Answer

Diagnosis of cancer

Answer

Screening of breast carcinoma

Answer

Detecting recurrence

Question 3

Erythropoietin is increased in all of the following conditions except:

Accepted Answer

Pancreatic carcinoma

Answer

Hepatocellular carcinoma

Answer

Renal cell carcinoma

Answer

Cerebellar hemangioblastoma

Question 4

Which histological feature characterizes an adenomatoid odontogenic tumour?

Accepted Answer

Tubular or duct-like cells

Answer

Polyhedral epithelial cells

Answer

Stellate shaped cells

Answer

Stratified squamous epithelial cells

Question 5

Proliferation of cells which are not native to that place is known as:

Accepted Answer

Both B and C

Answer

Harmatoma

Answer

Choriostoma

Answer

Fordyce's granule

Question 6

A patient presents with bilateral proptosis. Biopsy from the orbital region shows spindle cells arranged in compact fascicles with nuclear palisading forming Verocay bodies (Antoni A pattern), alternating with loose hypocellular myxoid areas (Antoni B pattern). Immunohistochemistry shows strong S-100 positivity. What is the most likely diagnosis?

Accepted Answer

Schwannoma

Answer

Leiomyoma

Answer

Rhabdomyosarcoma

Answer

Fibromatosis

Question 7

Which of the following is NOT a common childhood tumor?

Accepted Answer

Pleomorphic rhabdomyosarcoma

Answer

Wilm's tumor

Answer

Neuroblastoma

Answer

Embryonal rhabdomyoma

Question 8

Which of the following does NOT show antitumor activity?

Accepted Answer

Basophils

Answer

Cytotoxic T lymphocytes

Answer

Natural killer cells

Answer

Macrophages

Question 9

A 74-year-old woman presents with insidious onset of increasing back pain and malaise without a history of recent trauma. Her past medical history includes hypertension and breast cancer diagnosed 7 years ago, treated with surgery and adjuvant therapy. Physical examination reveals percussion tenderness over the lower spine. An X-ray of the lumbar spine shows lytic lesions compatible with metastatic bone disease, and her serum calcium level is elevated. Which of the following mediators is least likely to be involved in this patient's presentation?

Accepted Answer

Ectopic parathyroid hormone (PTH)

Answer

Interleukin-6 (IL-6)

Answer

Tumor necrosis factor (TNF)

Answer

Interleukin-1 (IL-1)

Question 10

Which of the following does not describe a documented mechanism of tumor-mediated immune evasion?

Accepted Answer

Antigenic variation

Answer

Down regulation of class I MHC

Answer

Secretion of TGF-b

Answer

Secretion of decoy molecules

Neoplasia — MCQs

Neoplasia — MCQs

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