Neoplasia Practice Questions

Q: Which electrolyte imbalance is characteristic of tumor lysis syndrome?

Hyperkalemia. **Explanation:** **Tumor Lysis Syndrome (TLS)** is an oncologic emergency caused by the rapid destruction of a large number of metabolically active tumor cells (most commonly in high-grade lymphomas and leukemias) following chemotherapy [1]. When these cells rupture, they release their intracellular contents into the systemic circulation. **Why Hyperkalemia is Correct:** Potassium is the primary intracellular cation. The massive lysis of tumor cells leads to an immediate release of potassium into the bloodstream, resulting in **Hyperkalemia**. This is the most dangerous component of TLS as it can lead to lethal cardiac arrhythmias. **Analysis of Incorrect Options:** * **Hypercalcemia:** In TLS, **Hypocalcemia** occurs, not hypercalcemia. This happens because the release of intracellular phosphorus leads to hyperphosphatemia; the excess phosphate binds to serum calcium, causing it to precipitate as calcium phosphate crystals. * **Hypokalemia:** This is the opposite of what occurs in TLS. Potassium levels rise due to cellular rupture. * **Increased serum sodium:** Sodium is primarily an extracellular ion; its levels are not characteristically elevated by the release of intracellular contents in TLS. **High-Yield Clinical Pearls for NEET-PG:** * **The Metabolic Tetrad of TLS:** 1. **Hyperkalemia** (Risk of arrhythmias) 2. **Hyperphosphatemia** (From breakdown of intracellular proteins) 3. **Hyperuricemia** (From catabolism of purines/nucleic acids) [1] 4. **Hypocalcemia** (Secondary to hyperphosphatemia) * **Renal Failure:** Hyperuricemia and calcium phosphate crystals can lead to acute kidney injury (AKI) [1]. * **Prophylaxis:** Aggressive hydration and **Allopurinol** (xanthine oxidase inhibitor) or **Rasburicase** (recombinant urate oxidase) are used to manage uric acid levels. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Kidney, pp. 941-942.

Q: A 3-year-old child presents with headaches and papilledema on funduscopic examination. One retina shows a vascular tumor, and a CT scan of the head reveals a cystic cerebellar tumor. What is the most likely condition this child is at high risk of developing later in life?

Bilateral renal cell carcinoma. **Explanation:** The clinical presentation of a **cystic cerebellar tumor** (likely Hemangioblastoma) and a **retinal vascular tumor** (Retinal Angioma) in a young child is classic for **Von Hippel-Lindau (VHL) syndrome**. VHL is an autosomal dominant neurocutaneous syndrome caused by a mutation in the *VHL* tumor suppressor gene on **chromosome 3p**. This condition predisposes patients to a specific constellation of benign and malignant tumors. The most significant long-term risk for these patients is the development of **Bilateral Renal Cell Carcinoma (RCC)**, specifically the clear cell subtype, which occurs in approximately 70% of affected individuals by age 60 and is a leading cause of mortality. **Analysis of Incorrect Options:** * **Option A:** Berry aneurysms are associated with **Autosomal Dominant Polycystic Kidney Disease (ADPKD)**, not VHL. * **Option C:** Cancers of the peripheral nerves (e.g., Malignant Peripheral Nerve Sheath Tumors) are associated with **Neurofibromatosis Type 1 (NF1)**. * **Option D:** Decreased GABA and acetylcholine in the striatum describes the pathophysiology of **Huntington’s Disease**, an autosomal dominant trinucleotide repeat disorder. **High-Yield Clinical Pearls for NEET-PG:** * **VHL Components:** Hemangioblastomas (Cerebellum/Spine/Retina), Pheochromocytoma, Renal Cell Carcinoma (Clear cell), and Pancreatic cysts/neuroendocrine tumors. * **Genetics:** VHL gene on **Chromosome 3** (Mnemonic: VHL has 3 letters). * **Screening:** Annual ophthalmologic exams and periodic abdominal imaging (MRI/CT) are essential for early detection of RCC and Pheochromocytoma.

Q: Hypercalcemia in the setting of squamous cell carcinoma of the esophagus is mainly due to which of the following?

Parathormone-related peptide secretion. Explanation: Hypercalcemia of malignancy is a common paraneoplastic syndrome, and in the context of **Squamous Cell Carcinoma (SCC)**—whether of the esophagus, lung, or head and neck—the most common mechanism is **Humoral Hypercalcemia of Malignancy (HHM)**. **1. Why Option D is Correct:** The tumor cells secrete **Parathyroid Hormone-related Protein (PTHrP)**. PTHrP mimics the action of PTH by binding to the same PTH-1 receptors in the bone and kidneys [1]. This leads to increased osteoclastic bone resorption and increased renal calcium reabsorption, resulting in systemic hypercalcemia [1]. Unlike true hyperparathyroidism, the endogenous PTH levels in these patients are typically suppressed [1]. **2. Why Other Options are Incorrect:** * **Option A (Bone metastasis):** While local osteolytic hypercalcemia occurs in cancers like breast cancer or multiple myeloma, it is less common than PTHrP secretion in esophageal SCC. * **Option B (Calcitonin excess):** Calcitonin actually *lowers* serum calcium levels. It is a marker for Medullary Thyroid Carcinoma, not SCC. * **Option C (Parathormone excess):** Ectopic production of true PTH by non-endocrine tumors is extremely rare. Hypercalcemia in malignancy is almost always due to the "related peptide" (PTHrP), not the hormone itself. **Clinical Pearls for NEET-PG:** * **Most common cause of HHM:** PTHrP secretion (associated with SCC of lung, esophagus, and cervix). * **1,25-dihydroxyvitamin D (Calcitriol) excess:** This is the mechanism for hypercalcemia in **Lymphomas** and granulomatous diseases (Sarcoidosis). * **Laboratory Findings in HHM:** High Calcium, Low PTH, High PTHrP, and Low/Normal Vitamin D levels. * **Treatment of Choice:** Aggressive IV hydration with Normal Saline, followed by IV Bisphosphonates (e.g., Zoledronic acid).

Question 1

Which electrolyte imbalance is characteristic of tumor lysis syndrome?

Accepted Answer

Hyperkalemia

Answer

Hypercalcemia

Answer

Hypokalemia

Answer

Increased serum sodium

Question 2

All of the following predispose to squamous cell carcinoma, EXCEPT?

Accepted Answer

Lichen planus of mouth

Answer

Bowen's disease

Answer

Inverted papilloma of nose

Answer

Chronic irritation of oral mucosa by jagged teeth

Question 3

Which of the following tumors has a strong hereditary factor?

Accepted Answer

Retinoblastoma

Answer

Breast carcinoma

Answer

Bronchogenic carcinoma

Answer

Pancreatic tumor

Question 4

Which of the following statements regarding oncogenes is incorrect?

Accepted Answer

Multiple growth factors can regulate the expression of oncogenes.

Answer

Oncogenes are derived from proto-oncogenes.

Answer

Oncogenes code for specific proteins.

Answer

Oncogenes can cause in vitro cell transformation in animals.

Question 5

What is the inheritance pattern of Von Hippel-Lindau (VHL) disease?

Accepted Answer

Autosomal dominant

Answer

Autosomal recessive

Answer

X linked recessive

Answer

X linked dominant

Question 6

A 3-year-old child presents with headaches and papilledema on funduscopic examination. One retina shows a vascular tumor, and a CT scan of the head reveals a cystic cerebellar tumor. What is the most likely condition this child is at high risk of developing later in life?

Accepted Answer

Bilateral renal cell carcinoma

Answer

Berry aneurysm of the basilar system

Answer

Cancer of a peripheral nerve

Answer

Choreiform movements related to decreased GABA and acetylcholine

Question 7

Which molecule inhibits the RAS gene?

Accepted Answer

GTPase activating protein

Answer

Cyclic GMP

Answer

Adenosine triphosphate

Answer

CD-kinase

Question 8

Which of the following viruses are not implicated in human malignancies?

Accepted Answer

Herpes simplex virus type I

Answer

Epstein-Barr virus

Answer

HTLV 1

Answer

Papilloma virus

Question 9

Hypercalcemia in the setting of squamous cell carcinoma of the esophagus is mainly due to which of the following?

Accepted Answer

Parathormone-related peptide secretion

Answer

Bone metastasis

Answer

Calcitonin excess

Answer

Parathormone excess

Question 10

Besides metastasis, which feature is most reliable in differentiating a benign from a malignant tumor?

Accepted Answer

Local invasion

Answer

Anaplasia

Answer

Dysplasia

Answer

Metastasis

Neoplasia — MCQs

Neoplasia — MCQs

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