To the Editor: Pancreatic metastasis is rare and usually comes from lung, breast, kidney, or colon tumors that metastasize to the pancreas through the blood stream.1

We present the case of a 52-year-old man with a history of smoking (30 pack-years) and childhood tuberculosis who complained of left suprascapular mechanical pain of one month's duration and increasing in spite of analgesic treatment. A chest x-ray showed an opacity in the upper left lobe with loss of volume and areas of emphysema. A computed tomography (CT) scan of the thorax and abdomen showed a mass in the upper left lobe 6x7 cm in size invading the chest wall and a hypodense lesion in the tail of the pancreas 1.3 cm long. Fiberoptic bronchoscopy revealed complete stenosis of the apicoposterior segment of the bronchus of the upper left lobe. Biopsies were positive for large-cell carcinoma. A bone scintigram was normal. We decided to perform a positron emission tomography (PET) scan, which revealed pathological uptake in the upper left lobe of the lung and another area of tracer accumulation in the tail of the pancreas. Mediastinoscopy ruled out mediastinal node involvement. Exeresis of the pancreatic nodule with body/tail pancreatectomy was performed. The pathologist diagnosed moderately differentiated carcinoma that was probably metastatic. No invasion of the peripancreatic lymph nodes or those of the hilus of the spleen was observed. A left radical pneumonectomy was then performed by left thoracotomy, with resection of the third, fourth, and fifth ribs. The resection margins were tumor-free and the patient's course was favorable, without complications.

Lung, kidney, breast, and colon tumors may metastasize to the pancreas. Other neoplasms for which pancreatic involvement has occasionally been described are melanoma, chondrosarcoma, sarcoma, and endometrial cancer. The lung tumor that most commonly metastasizes to the pancreas is small cell carcinoma. In the series of Maeno et al,2 pancreatic invasion was observed in 10%. Pancreatic involvement is much less common in adenocarcinomas (2.4%), large cell carcinomas (1.9%), and squamous cell carcinoma (1.1%). Additional intraabdominal sites, mostly hepatic and suprarenal, have been observed in 97% of the cases of lung tumor metastasis to the pancreas.3 Pancreatic metastases are usually asymptomatic. The diagnostic technique of choice is an abdominal CT scan, and the role of PET is still uncertain. PET has been reported to detect up to 10% of unsuspected lung cancer metastases not observed by CAT.4 Pathology provides the only sure diagnostic method, and percutaneous fine needle aspiration must therefore be considered for all operable patients.

The treatment of pancreatic metastasis is aggressive resection of the lesion. Although prognosis depends on the nature of the primary tumor, it is unfavorable in all cases.