Devita, Hellman, and Rosenberg's Cancer

LWBK1006-19 LWW-Govindan-Review December 7, 2011 21:24

222 DeVita, Hellman, and Rosenberg’s CANCER: Principles and Practice of Oncology Review

ANSWERS

Answer 19.1. The answer is D.

This middle-aged woman has an anterior mediastinal mass that appears

localized on radiologic imaging. Thymomas are the most common tumors

arising in the anterior mediastinum. They occur in patients of all ages,

and approximately one-half of patients are symptomatic because of com-

pression of mediastinal structures (e.g., pain, cough, superior vena cava

syndrome) or associated paraneoplastic syndromes. Paraneoplastic syn-

dromes can be identified in up to 70% of patients with thymoma but

are uncommon in patients with thymic carcinoma. Myasthenia gravis is

the most common paraneoplastic syndrome associated with thymoma,

although a wide variety of other syndromes, primarily caused by autoim-

mune dysregulation, have been reported. Small cell lung cancer typically

presents with a central lung mass and bulky mediastinal lymphadenopa-

thy, and nearly all patients have a history of tobacco use. Pericardial cysts

occur primarily in the middle mediastinum and, in adults, are usually

asymptomatic. NSGCTs occur predominantly in young men, and 80% to

85% are associated with elevations of-fetoprotein and/or-hCG.

Answer 19.2. The answer is B.

This child presents with radicular pain and a noninvasive posterior medi-

astinal mass arising from the paravertebral sulcus. Thoracic neurogenic

tumors occur most commonly in the posterior mediastinum and account

for 75% of tumors in this location. They are predominantly seen in chil-

dren, in whom they are frequently malignant, and in young adults, in

whom they are usually benign. In children, neurogenic tumors account

for nearly half of all mediastinal neoplasms. Histologic subtypes of tho-

racic neurogenic tumors include neurofibroma, neurilemmoma, neurosar-

coma, ganglioneuroma, paraganglioma, and neuroblastoma. Because

thoracic neurogenic tumors arise in the paravertebral sulcus, they fre-

quently cause pain and a variety of neurologic symptoms, including spinal

cord compression, paresthesia, Horner’s syndrome, and muscular atro-

phy. Surgical resection is the primary treatment option for all thoracic

neurogenic tumors if it can be accomplished with acceptable risk. Obser-

vation is an option for asymptomatic patients with benign tumors who are

poor candidates for surgery. Thymomas are found predominantly in the

anterior mediastinum, although ectopic thymic tissue can rarely result in

tumors in other mediastinal compartments. Mediastinal germ cell tumors

are uncommon in young children and nearly always arise in the ante-

rior mediastinum. Lymphomas account for 26% of mediastinal tumors

in adults, but only 9% in children, and are mainly noted in the anterior

mediastinum.

Answer 19.3. The answer is C.

Transesophageal ultrasonograpy provides the best assessment of the inva-

siveness of a posterior mediastinal mass, while the other modalities have