Neoplastic Processes

A 42-year-old female presents to the clinic after noticing a painless lump in the anterior portion of her neck while swallowing. She has no symptoms of hyperthyroidism or hypothyroidism, and she denies any history of head or neck irradiation. Physical examination reveals a firm, mobile, 2.5-cm nodule in the right lobe of the thyroid gland. No cervical lymphadenopathy is appreciated. Laboratory testing shows a serum thyroid-stimulating hormone (TSH) level of 1.8 mIU/L (normal: 0.4-4.0 mIU/L). Arrange the following clinical interventions in the most appropriate chronological order for the definitive evaluation and management of this patient's condition, assuming findings at each step strongly suggest a primary differentiated thyroid malignancy.

A 68-year-old woman is brought to the emergency department by her family due to progressive confusion, weakness, and severe constipation over the past week. She has a 40-pack-year smoking history. Her vital signs are within normal limits. Physical examination reveals lethargy and diminished deep tendon reflexes. Laboratory studies reveal:

Serum calcium: 14.1 mg/dL
Serum phosphorus: 2.1 mg/dL
Intact parathyroid hormone (PTH): 8 pg/mL (normal: 10-65 pg/mL)

A chest radiograph demonstrates a large, centrally located cavitary mass in the right lung. Which of the following best describes the underlying mechanism of this patient's electrolyte abnormality?

During a routine health maintenance examination, a physician palpates an asymptomatic, firm nodule in the right anterior neck of an adult female patient. The patient denies any recent weight changes, palpitations, dysphagia, or hoarseness. Her vital signs are within normal limits.

Laboratory evaluation reveals a serum thyroid-stimulating hormone (TSH) level of $2.1 \text{ mIU/L}$ (normal: $0.4 - 4.0 \text{ mIU/L}$) and a free T4 of $1.3 \text{ ng/dL}$ (normal: $0.9 - 1.7 \text{ ng/dL}$).

A dedicated neck ultrasound demonstrates a $1.8\text{-cm}$ solid, hypoechoic nodule in the right thyroid lobe with irregular margins and punctate microcalcifications. A subsequent fine-needle aspiration biopsy is performed, revealing clusters of cells that demonstrate pale, empty-appearing nuclei, prominent longitudinal nuclear grooves, and scattered laminated calcific spherules.

Based on the confirmed diagnosis, which of the following correctly pairs the predominant molecular pathogenesis of this patient's neoplasm with a principle of its clinical management?

A 68-year-old man is evaluated for progressive headaches and left-sided weakness over the past month. Magnetic resonance imaging of the brain reveals a 4-cm, ring-enhancing lesion in the right frontal lobe with extensive surrounding edema, characteristic of glioblastoma. The patient undergoes surgical resection. Pathologic examination of the tissue demonstrates pseudo-palisading necrosis and prominent microvascular proliferation. The rapid growth and vascularization of this patient's tumor are primarily driven by a cascade of molecular events initiated by the tumor microenvironment. Arrange the following molecular and cellular events in the correct chronological order to describe the mechanism of tumor-induced angiogenesis in this patient.

A 64-year-old man with chronic hepatitis C virus infection is evaluated for abdominal distension, fatigue, and a $5\text{-kg}$ ($11\text{-lb}$) weight loss over the past two months. Three weeks ago, he was admitted to the hospital for an episode of hematemesis. Esophagogastroduodenoscopy at that time revealed large esophageal varices with red wale signs; he received endoscopic band ligation and was discharged on nadolol.

Vital signs today are within normal limits. Physical examination shows scleral icterus, palmar erythema, and a palpable, hard liver edge $4 \text{ cm}$ below the right costal margin.

Laboratory studies show:
Total bilirubin: $2.4 \text{ mg/dL}$
Aspartate aminotransferase (AST): $95 \text{ U/L}$
Alanine aminotransferase (ALT): $88 \text{ U/L}$
Platelet count: $85,000/\mu\text{L}$
Alpha-fetoprotein: $2,100 \text{ ng/mL}$

A multiphase abdominal CT scan reveals a $7\text{-cm}$ hypervascular mass in the right hepatic lobe that demonstrates avid arterial phase enhancement and rapid portal venous washout. The mass invades the right main branch of the portal vein. There is no evidence of extrahepatic metastasis.

The multidisciplinary tumor board considers initiating the preferred first-line systemic combination regimen consisting of atezolizumab and bevacizumab. However, the oncologist determines that this specific regimen is currently contraindicated for this patient.

This contraindication is primarily due to the drug-induced impairment of which of the following physiological processes?

An oncology care team is preparing to initiate induction chemotherapy for a recently admitted patient.

Demographics: $19$-year-old male of Mediterranean descent
Vital Signs: Temperature $37.2^\circ\text{C}$ ($99.0^\circ\text{F}$), HR $98\text{/min}$, BP $118/74\text{ mmHg}$, RR $16\text{/min}$
Physical Exam: Noticeably enlarged, non-tender submandibular and cervical lymph nodes. No hepatosplenomegaly.
Laboratory Findings:
- WBC: $12,500\text{/mm}^3$
- Hemoglobin: $13.8\text{ g/dL}$
- Platelets: $180,000\text{/mm}^3$
- Uric acid: $11.2\text{ mg/dL}$ (Normal: $4.0-8.5\text{ mg/dL}$)
- LDH: $950\text{ U/L}$ (Normal: $140-280\text{ U/L}$)
- Creatinine: $1.1\text{ mg/dL}$

A peripheral blood smear demonstrates numerous medium-sized atypical lymphocytes with vacuolated, deeply basophilic cytoplasm. Cytogenetic analysis confirms a $t(8;14)$ translocation. Given the high proliferation index and elevated baseline uric acid, the patient is at significant risk for an oncologic emergency characterized by massive release of intracellular metabolites. The attending physician recommends administering a recombinant enzyme that converts a relatively insoluble purine degradation product into a highly soluble compound. However, before administration, the physician orders an erythrocyte enzyme assay; if this assay demonstrates a specific underlying deficiency, the recombinant agent is absolutely contraindicated.

Which of the following best explains the pathophysiologic mechanism underlying this absolute contraindication?

A 28-year-old man of Mediterranean descent is admitted to the oncology unit for initiation of induction chemotherapy. He was recently diagnosed with a highly aggressive B-cell non-Hodgkin lymphoma characterized by a $t(8;14)$ chromosomal translocation. Baseline laboratory studies show a serum uric acid level of $11.5 \text{ mg/dL}$, lactate dehydrogenase of $1,250 \text{ U/L}$, and a serum creatinine of $1.1 \text{ mg/dL}$. To mitigate the risk of an impending oncologic emergency, the patient is administered a recombinant enzyme therapy that directly degrades uric acid into a highly soluble inactive metabolite. Forty-eight hours later, the patient develops sudden-onset fatigue, scleral icterus, and dark urine. His hemoglobin concentration has decreased from $14.2 \text{ g/dL}$ to $8.4 \text{ g/dL}$. A peripheral blood smear reveals the presence of bite cells. The medication that precipitated this patient's acute deterioration is absolutely contraindicated in individuals who have a primary hereditary inability to synthesize adequate amounts of which of the following molecules?

Match each patient's clinical presentation of a suspected paraneoplastic syndrome with the most likely underlying neoplastic etiology and its associated pathophysiologic mechanism.

A 22-year-old man presents to the gastroenterology clinic for evaluation of intermittent bright red blood per rectum over the past two months. He reports no abdominal pain, unexplained weight loss, or changes in stool caliber. His father died of metastatic colorectal cancer at age 38, and a paternal aunt underwent abdominal surgery for an unknown malignancy in her 30s. His temperature is 37.0°C (98.6°F), blood pressure is 118/76 mmHg, pulse is 72/min, and respirations are 14/min. Physical examination reveals a soft, non-tender abdomen without organomegaly. Digital rectal examination demonstrates normal sphincter tone with small amounts of bright red blood on the examining finger. Given his striking family history, a colonoscopy is performed and reveals over 150 small adenomatous polyps carpeting the entire colon and rectum. Biopsies of several polyps confirm tubular adenomas with low-grade dysplasia. Which of the following best describes the underlying foundational mechanism of this patient's condition and the most appropriate definitive management?

A 44-year-old man presents to the oncology clinic for treatment planning of newly diagnosed metastatic colorectal cancer. He initially presented to his primary care physician with fatigue and was found to have iron deficiency anemia. A subsequent colonoscopy revealed a 3.5-cm ulcerated mass in the ascending colon, and a computed tomography scan of the abdomen and pelvis showed multiple hepatic metastases. His family history is notable for his father dying of colon cancer at age 48 and a paternal aunt who was treated for endometrial cancer at age 46.

Physical examination reveals pale conjunctivae and a palpable liver edge 3 cm below the right costal margin. Laboratory studies show a hemoglobin of 9.2 g/dL.

Biopsy of the hepatic lesion confirms metastatic adenocarcinoma. Immunohistochemical staining of the biopsy specimen demonstrates intact expression of MLH1 and PMS2 proteins, but absent expression of MSH2 and MSH6 proteins. The oncologist recommends initiating therapy with a programmed cell death protein 1 (PD-1) inhibitor.

Which of the following molecular characteristics best explains why this patient's neoplasm is highly susceptible to this specific pharmacologic therapy?

Match each clinical scenario describing a patient with an advanced malignancy who has developed acquired resistance to a targeted antineoplastic therapy with the most likely underlying molecular mechanism of resistance.

A 55-year-old man undergoes a screening colonoscopy, which reveals a 2-cm polyp in the descending colon. Biopsy shows a tubulovillous adenoma with high-grade dysplasia. The patient is scheduled for a polypectomy. The development of such lesions into invasive adenocarcinoma typically follows a well-characterized stepwise accumulation of genetic and epigenetic alterations.

Arrange the following molecular events in the typical chronological order of the classic adenoma-carcinoma sequence in colorectal cancer, from earliest (first) to latest (last).

Match each classic paraneoplastic clinical presentation with its most strongly associated primary neoplasm.

A 62-year-old woman is diagnosed with invasive ductal carcinoma of the breast. Pathologic evaluation reveals distant metastasis to the bone. To establish this distant metastasis, the neoplastic cells must have completed a series of complex biological steps known as the metastatic cascade. Arrange the following critical events of the metastatic cascade in the correct chronological sequence.

A $62$-year-old woman is evaluated in the oncology clinic for progressive shortness of breath and right upper quadrant abdominal fullness over the past three weeks. She has a history of metastatic non-small cell lung cancer (NSCLC) diagnosed $20$ months ago. At the time of initial diagnosis, molecular testing of the lung primary tumor revealed an epidermal growth factor receptor (EGFR) exon $19$ deletion. She was started on osimertinib, with a robust partial response. She has no other significant past medical history and has never smoked. Current vital signs are within normal limits.

Physical examination reveals decreased breath sounds at the right lung base and a palpable, slightly tender liver edge $4$ cm below the right costal margin. Restaging computed tomography (CT) of the chest, abdomen, and pelvis demonstrates enlargement of the primary right lung mass, new right-sided pleural effusion, and multiple new, hypervascular hepatic lesions.

A liquid biopsy (cell-free DNA) is performed and confirms the presence of the original EGFR exon $19$ deletion but is negative for secondary EGFR mutations, including T790M and C797S, as well as MET amplification. Subsequently, an ultrasound-guided core needle biopsy of one of the new hepatic lesions is performed. Histopathologic evaluation of the liver specimen reveals sheets of small cells with scant cytoplasm, finely granular nuclear chromatin, and absent glandular architecture. Immunohistochemical staining is strongly positive for synaptophysin and chromogranin A.

Based on the patient's new clinicopathologic findings, which of the following is the most appropriate next step in management?

A 42-year-old woman is evaluated for a recurrence of high-grade serous ovarian carcinoma. She has a strong family history of breast and ovarian malignancies and is known to carry a deleterious germline mutation in the BRCA1 gene. Her oncologist initiates therapy with olaparib, an oral targeted agent that exploits the principle of synthetic lethality. Arrange the following molecular and cellular events in the correct chronological sequence that mediates the antineoplastic efficacy of this pharmacological intervention.

Match each patient's clinical and histopathologic presentation with the primary molecular mechanism driving their underlying neoplastic process.

A $45$-year-old man is evaluated following a screening colonoscopy that revealed a $4\text{-cm}$ ulcerated mass in the ascending colon. He has no significant past medical history. His family history is notable for a father who died of colon cancer at age $50$ and a paternal aunt who was diagnosed with endometrial cancer at age $48$. Biopsy of the colonic mass confirms invasive adenocarcinoma. Immunohistochemical staining of the tumor specimen demonstrates an absence of nuclear staining for MLH1 and PMS2 proteins, while MSH2 and MSH6 proteins maintain normal nuclear expression. Further molecular analysis of the tumor reveals wild-type $BRAF$ and high microsatellite instability (MSI-H). Based on the underlying molecular pathogenesis of this patient's neoplasm, which of the following is the most appropriate next step in management?

A 54-year-old woman with high-grade serous ovarian carcinoma is initiated on systemic induction therapy with carboplatin and paclitaxel. Following two cycles of treatment, imaging demonstrates a significant reduction in her tumor burden. The platinum-based component of her regimen exerts its primary antineoplastic effect by triggering the intrinsic apoptotic pathway in rapidly dividing cells.

Arrange the following cellular and molecular events in the correct chronological sequence to describe this mechanism of tumor cell death, beginning with the initial pharmacologic insult and ending with the activation of the executioner phase.

A 31-year-old male is admitted to the intensive care unit with acute-onset diffuse mucosal bleeding, petechiae across his torso, and severe fatigue. Vital signs are temperature $37.8^\circ\text{C}$ ($100.0^\circ\text{F}$), blood pressure $110/70\text{ mmHg}$, heart rate $105/\text{min}$, and respiratory rate $18/\text{min}$. Laboratory studies show:

- Leukocytes: $2,100/\mu\text{L}$
- Hemoglobin: $8.4\text{ g/dL}$
- Platelets: $24,000/\mu\text{L}$
- Prothrombin time: $19\text{ seconds}$
- Partial thromboplastin time: $46\text{ seconds}$
- Fibrinogen: $85\text{ mg/dL}$
- D-dimer: $>10,000\text{ ng/mL}$

Peripheral blood smear reveals numerous abnormal promyelocytes with bilobed nuclei, abundant granules, and multiple needle-like cytoplasmic inclusions. The underlying neoplastic process involves a chromosomal translocation that creates a fusion protein, which abnormally represses gene transcription. Based on the suspected molecular pathology, which of the following is the most appropriate next step in management?