History :
This 48 y/o gentleman, a heavy smoker consuming 1PPD of cigarettes for 30years, had been well until two month ago when dry cough was noted. Facial swelling were noted since 1 month ago.

Image finding :
-A huge mass at least 9 cm in diameter on axil plane located at middle mediastinum predominate at right side.
-There is tumor encasement of the right main pulmonary artery and azygos vein.
-There is anterior displacement of SVC and direct tumor growth into the SVC.
-Enlarged right hilar lymph node is also noted.
-There is also encasement of the right upper lobe bronchus.
-Mass effect of the tumors upon the intrathoracic trachea which is compressed and slightly deviated to left side.

Diagnosis :
Small cell lung cancer, right upper lobe, limited stage, with superior vena cava syndrome.

Discussion :
Small cell undifferentiated carcinoma (15%) :
-Strongly associated with cigarette smoking Rapid growth + high metastatic potential (early metastases in 60-80% at time of diagnosis); -should be regarded as systemic disease regardless of stage;
-virtually never resectable
-smooth-appearing mucosal surface endoscopically
-ectopic hormone production: Cushing syndrome, inappropriate secretion of
ADH
-Most common primary lung cancer causing superior vena caval obstruction (due to extrinsic compression / endoluminal thrombosis / invasion)!

Location:
-90% central within lobar / mainstem bronchus (primary tumor rarely visualized)
-typically large hilar / perihilar mass often associated with mediastinal widening (from adenopathy)
-extensive necrosis + hemorrhage
-small lung lesion (rare)
Staging evaluation: CT of abdomen + head, bone scintigraphy, bilateral bone marrow biopsies

SUPERIOR VENA CAVA SYNDROME
=obstruction of SVC with development of collateral pathways

Etiology: 

1. Malignant lesion (80-90%)
   • Bronchogenic carcinoma (>50%)
   • Lymphoma
2. Benign lesion 
• Granulomatous mediastinitis (usually histoplasmosis, sarcoidosis, TB)
• Substernal goiter
• .Ascending aortic aneurysm
• Pacer wires / central venous catheters (23%)
• Constrictive pericarditis

Collateral routes:

1. Esophageal venous plexus = "downhill varices" (predominantly upper 2/3)
2. Azygos + hemiazygos veins
3. Accessory hemiazygos + superior intercostal veins = "aortic nipple" (visualization in normal population in 5%)
4. Lateral thoracic veins + umbilical vein
5. Vertebral veins

*head and neck edema (70%)
*cutaneous enlarged venous collaterals
*headache, dizziness, syncope
*with benign etiology: slower onset + progression, both sexes, 25-40 years of age
*with malignancy: rapid progression within weeks, mostly males, 40-60 years of age
*proptosis, tearing
*dyspnea, cyanosis, chest pain
*hematemesis (11%)
-superior mediastinal widening (64%)
-encasement / compression / occlusion of SVC
-dilated cervical + superficial thoracic veins (80%)
 SVC thrombus

NUC:
-increased tracer uptake in quadrate lobe + posterior aspect of medial segment of left lobe (umbilical pathway toward liver when injected in upper extremity)