15 Neoplasms of the Mediastinum

Gregory P. Kalemkerian

QUESTIONS

Each of the numbered items below is followed by lettered answers. Select the ONE lettered answer that is BEST in each case unless instructed otherwise.

Question 15.1 A 46-year-old woman presents with dull anterior chest pain. She is a lifelong nonsmoker. Her medical history is significant for Hashimoto thyroiditis, for which she has been taking levothyroxine for 1 year. Examination is unremarkable. Chest radiograph reveals clear lung fields with a retrosternal density. Computed tomography (CT) scan shows a 4-cm, smooth, anterior mediastinal mass. Laboratory studies show normal blood counts, blood chemistry, lactate dehydrogenase (LDH), α-fetoprotein (AFP), and β-human chorionic gonadotropin (β-hCG). What is the most likely diagnosis?

A. Small cell lung cancer (SCLC)

B. Thymoma

C. Pericardial cyst

D. Nonseminomatous germ cell tumor (NSGCT)

Question 15.2 Which of the following statements regarding thymoma is TRUE?

A. The incidence of thymoma is higher in women than in men.

B. Thymoma is most commonly seen in people under 30 years old.

C. The most common site of metastatic spread for thymoma is bone.

D. Complete surgical resection is the most important predictor of long-term survival for patients with thymoma.

Question 15.3 Which of the following statements regarding myasthenia gravis are TRUE? (Select three correct responses).

A. Myasthenia gravis occurs in 30% to 50% of people with thymoma.

B. Ocular symptoms are the most common initial manifestation of myasthenia gravis.

C. Myasthenia gravis is caused by autoantibodies against presynaptic muscarinic acetylcholine receptors.

D. Thymoma is diagnosed in 15% of people with myasthenia gravis.

Question 15.4 A 32-year-old man presents with an anterior mediastinal mass that was identified incidentally on a chest radiograph done as part of an employment examination. He is asymptomatic and a lifelong nonsmoker, with no significant medical history. Examination is unremarkable. CT scan shows a 4-cm, smooth, lobulated, anterior mediastinal mass without local invasion. Resection of the mass reveals an encapsulated, lymphocyte-rich thymoma (World Health Organization [WHO] type B1) with no capsular invasion. He recovers from surgery without complications. What is the most appropriate next step in the management of this patient?

A. Clinical surveillance

B. Adjuvant radiotherapy alone

C. Adjuvant chemotherapy alone

D. Adjuvant chemotherapy plus radiotherapy

Question 15.5 Which of the following are the most appropriate systemic therapy options for the treatment of advanced, stage IV thymoma? (Select two correct responses)

A. Gemcitabine and docetaxel

B. Cyclophosphamide, doxorubicin, and cisplatin

C. Cisplatin plus etoposide

D. Carboplatin plus paclitaxel

Question 15.6 Which of the following paraneoplastic syndromes are associated with thymoma? Select all that apply.

A. Myasthenia gravis and pure red cell aplasia

B. Subacute cerebellar degeneration and gynecomastia

C. Polymyositis and hypothyroidism

D. Opsoclonus/myoclonus syndrome and Pel–Ebstein fever

Question 15.7 Which of the following molecularly targeted therapies has meaningful clinical activity in advanced thymoma?

A. Octreotide, a somatostatin analog

B. Erlotinib, an EGFR inhibitor

C. Imatinib, a c-kit inhibitor

D. Sorafenib, a multitargeted kinase inhibitor

Question 15.8 A previously healthy 51-year-old man presents with facial and bilateral upper extremity edema that has progressed over the past 2 weeks. Examination reveals moderate facial, cervical, and bilateral upper extremity edema and prominent anterior chest wall vasculature. He is tachycardic, but his heart sounds are regular and his lungs are clear. There is no lower extremity edema. CT scan of the chest shows a large anterior mediastinal mass encasing and narrowing the superior vena cava, and invading the pericardium and upper lobe of the left lung. There are numerous dilated, intrathoracic collateral vessels. An experienced thoracic surgeon deems that the lesion is primarily unresectable. Mediastinotomy with biopsy of the mass reveals well-differentiated thymic carcinoma (WHO type B3). PET scan shows the large FDG-avid mediastinal mass with no evidence of metastatic disease. What is the most appropriate management of this patient?

A. Palliative radiotherapy followed by chemotherapy

B. Definitive radiotherapy with concurrent chemotherapy

C. Neoadjuvant chemotherapy followed by surgical resection and postoperative radiotherapy

D. Palliative chemotherapy alone

Question 15.9 Which of the following histologic subtypes is associated with a more favorable outcome in patients with thymic carcinoma?

A. Clear cell carcinoma

B. Well-differentiated squamous cell carcinoma

C. Sarcomatoid differentiation

D. Small cell carcinoma

Question 15.10 Thymic carcinoid is associated with which genetic predisposition syndrome?

A. Multiple endocrine neoplasia type 1 (MEN 1)

B. Louis–Bar syndrome

C. Li–Fraumeni syndrome

D. Cowden syndrome

Question 15.11 A 21-year-old man presents with anterior chest pain and cough. Physical examination is unremarkable and his performance status is excellent. Chest radiography shows widening of the superior mediastinum. CT scan shows a 6-cm anterior mediastinal mass encasing the trachea and great vessels and three 1-cm pulmonary nodules. CT scan of the abdomen and pelvis and a testicular ultrasound examination are normal. Laboratory studies reveal normal blood counts and blood chemistry, LDH of 880 IU/L (normal, 120 to 240 IU/L), AFP of 1,800 ng/mL (normal, <8 ng/mL), and β-hCG of 1.2 mIU/mL (normal, <5 mIU/mL). What is the most likely diagnosis?

A. Hodgkin lymphoma

B. Benign teratoma

C. Nonseminomatous germ cell tumor (NSGCT)

D. Seminoma

Question 15.12 Which of the following statements is TRUE regarding mediastinal germ cell tumors?

A. The incidence of malignant mediastinal germ cell tumors is the same in men and women.

B. Seminoma is the most common mediastinal germ cell tumor.

C. An elevated serum AFP in a patient with biopsy-proven seminoma indicates the presence of a nonseminomatous component.

D. Mediastinal NSGCTs are associated with better overall survival than testicular NSGCTs.

Question 15.13 A 33-year-old woman presents with a cough and dyspnea on moderate exertion. Physical examination shows an anxious woman with a pulse of 110 beats/min, a respiratory rate of 24 breaths/min, and mild stridor. Lungs are otherwise clear to auscultation, and heart sounds are regular. Chest radiography shows a large anterior mediastinal mass with narrowing of the midtrachea. CT scan shows a 10-cm, heterogeneous, anterior mediastinal mass with foci of dense calcification that compresses the trachea and narrows, but does not obstruct, the superior vena cava. Laboratory studies reveal normal blood counts, blood chemistry, LDH, carcinoembryonic antigen (CEA), AFP, and β-hCG. She undergoes complete resection of the mass. Pathologic evaluation reveals a multicystic mass with foci of mature gland formation, respiratory epithelium, cartilage, and bone. There is no invasion into adjacent structures, and surgical margins are negative. What is the most appropriate management of this patient?

A. Clinical surveillance

B. Adjuvant radiotherapy

C. Cisplatin plus etoposide × 4 cycles

D. Doxorubicin plus ifosfamide × 6 cycles

Question 15.14 A 23-year-old man presents with hoarseness, cough, and anterior chest pain. He has a 10 pack-year smoking history. Physical examination is normal. Chest radiography shows a large left mediastinal mass and clear lung fields. CT scan of the chest shows a 5-cm irregular left paratracheal mass. Serum CEA, β-hCG, and AFP are normal. Left mediastinotomy with biopsy of the anterior mediastinal mass reveals a poorly differentiated malignant neoplasm that is immunohistochemically negative for leukocyte common antigen, vimentin, S100, TTF1 and chromogranin, but positive for low–molecular-weight cytokeratin. Genetic studies reveal no B- or T-cell rearrangements, and karyotypic analysis shows aneuploidy and isochromosome 12p. Which of the following is the most appropriate therapy for this patient?

A. Cisplatin plus etoposide

B. Cisplatin, etoposide, and bleomycin (BEP)

C. Concurrent chemotherapy and radiation therapy

D. Cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP)

Question 15.15 A previously healthy 28-year-old man presents with fatigue and vague chest discomfort. A chest radiograph shows a widened mediastinum, and a CT scan confirms a 9-cm anterior mediastinal mass with focal hemorrhage that fills the substernal space and invades into the upper lobe of the left lung. Laboratory studies show LDH of 850 IU/L (normal, 120 to 240 IU/L), AFP of 8,700 ng/mL (normal, <8 ng/mL), and β-hCG of 220 mIU/mL (normal, <5 mIU/mL). Biopsy confirms embryonal carcinoma with elements of choriocarcinoma. After four cycles of cisplatin, etoposide, and bleomycin (BEP), a CT scan shows marked shrinkage of the mediastinal mass, now 3 cm in maximal diameter. One month after completion of therapy, LDH is 150 IU/L, AFP is 5 ng/mL, and β-hCG is 2.4 mIU/mL. Which of the following is the most appropriate management of this patient?

A. Clinical surveillance

B. Cisplatin, ifosfamide, and vinblastine (VIP)

C. Two additional cycles of cisplatin, etoposide, and bleomycin (BEP)

D. Resection of the residual mediastinal mass

Question 15.16 A 22-year-old man has a retrosternal mass identified on a chest radiograph done during his enlistment into military service. He is an asymptomatic nonsmoker with no significant medical history. CT scan shows a 2.5-cm smooth anterior mediastinal mass without local invasion. Serum LDH, β-hCG, and AFP are normal. Testicular ultrasound is normal. He refuses primary surgical resection. A percutaneous core biopsy shows pure seminoma. Which of the following is the most appropriate management of this patient?

A. Surgical resection

B. Radiotherapy

C. Cisplatin, etoposide, and bleomycin (BEP)

D. Cisplatin plus etoposide followed by surgical resection

Question 15.17 Mediastinal nonseminomatous germ cell tumors are associated with which of the following? (Select two correct responses)

A. Myasthenia gravis

B. Acute megakaryocytic leukemia

C. Klinefelter syndrome

D. Thymic carcinoid

Question 15.18 A 30-year-old man presents with chest tightness and shortness of breath. A chest radiograph shows a large mediastinal mass. CT scan shows a 9-cm, lobulated, anterior mediastinal mass invading the left lung and the pericardium with a small pericardial effusion, a 3-cm right paratracheal lymph node, and a 5-cm subcarinal lymph node. Echocardiogram shows no tamponade. Serum LDH is 440 IU/L (normal, 120 to 240 IU/L), but AFP and β-hCG are normal. Testicular ultrasound is normal. Bronchoscopic core biopsy of the subcarinal mass reveals seminoma. Which of the following is the most appropriate initial management of this patient?

A. Carboplatin plus etoposide

B. Radiotherapy

C. Surgical resection

D. Cisplatin plus etoposide

Question 15.19 A previously healthy 45-year-old man presents with hoarseness and vague chest discomfort. A chest radiograph shows a widened mediastinum, and a CT scan confirms a large anterior mediastinal mass encasing the trachea and abutting the superior vena cava, left pleura, and superior pericardium. Serum AFP is normal, but β-hCG is 10 mIU/mL (normal, <5 mIU/mL). Biopsy shows seminoma. He is treated with cisplatin, etoposide, and bleomycin (BEP). CT scan after treatment shows marked shrinkage of the mediastinal mass, now 2 cm in maximal diameter. β-hCG is 1.2 mIU/mL. Which of the following is the most appropriate management of this patient?

A. Clinical surveillance

B. Cisplatin, ifosfamide, and vinblastine (VIP)

C. Resection of the residual mediastinal mass

D. Involved-field radiotherapy

Question 15.20 Which of the following is TRUE for mediastinal germ cell tumors according to the International Germ Cell Consensus Classification (IGCCC)?

A. All pure mediastinal seminomas are good risk

B. All mediastinal nonseminomatous germ cell tumors are poor risk

C. Pure mediastinal seminomas with nonpulmonary visceral metastases are poor risk

D. Mediastinal nonseminomatous germ cell tumors without visceral metastases are intermediate risk

Stay updated, free articles. Join our Telegram channel

Join