Multiple Lesions

• Multiple discrete lung lesions occur due to widely disseminated hematogenous metastasis. 
• The pattern can vary from 
  • diffuse micronodular shadows resembling miliary disease
  • to multiple large well defined masses cannon balls.
• Occasionally, cavitation or calcification can be noted. 
• Symptoms
  • Due to the interstitial location, these lesions are often asymptomatic. 
  • Cough and hemoptysis are the usual symptoms. 
• Needle aspiration or trans-bronchial biopsy would be the procedure of choice for confirmation of the nature of the lesion. 
• Treatment
  • Chemotherapy is the choice when the tumor is responsive.
  • Occasional surgical resection of multiple lesions were attempted with some reported success. 
  • In refractory hemoptysis, selective occlusion of bronchial arteries by teflon is a consideration.

Cannon balls

52 Y/O, W/M with Ca of the colon with cannon ball mets.

• Neoplasms with rich vascular supply draining directly into the systemic venous system often present in this fashion.

Miliary Pattern: This presentation is seen in patients with 

• thyroid carcinoma 
• renal cell carcinoma 
• sarcoma of the bone 
• trophoblastic disease.

Cavitating lesions:

Cavitating mets in a patient with squamous cell cancer of larynx.

• Cavitation is identified in 4% of metastatic deposits and, as with primary bronchial carcinoma, is more likely in squamous cell lesions.
• Colon, anus, cervix, breast and larynx account for 69% of such occurrences. 
• Generally, small thin walled metastases usually indicate a primary site in the head or neck, where as most large, thick walled secondaries arise from the gastrointestinal tract. 
• Avascular necrosis of the lesion secondary to vascular occlusion, is the presumed mechanism for cavitation.

Calcification

• Calcification or ossification is rarely visible in metastasis to the thorax.
  • Calcification of metastasis from ovarian, thyroid, breast and mucin producing gastro-intestinal neoplasms. 
  • Calcification in lymphomatous nodes has most often occurred following therapy.
  • Lung metastasis may also calcify following therapy. 
  • Almost all calcified or ossified lung metastasis occurring prior to therapy are due to osteosarcoma or chondrosarcoma. 
  • Isolated cases of such metastasis have also been reported with synovial sarcoma and giant cell tumor of the bone.