Four cases of invasive anterior mediastinal tumors definitively diagnosed by the chamberlain procedure.

Percutaneous needle biopsy, commonly used for a definitive diagnosis of anterior mediastinal tumors, is sometimes inconclusive because of the small size of the biopsy specimens and the histologic heterogeneity of the tumors. We herein report 4 cases of invasive anterior mediastinal tumors, in which the definitive diagnosis was made using the Chamberlain procedure. [Case 1] A 33-year-old man was found to have an anterior mediastinal tumor on chest X-ray and computed tomography (CT). The tumor was histologically diagnosed as thymic carcinoma (squamous cell carcinoma) using the Chamberlain procedure. After 3 courses of preoperative chemotherapy, the patient underwent surgery and postoperative radiotherapy. He remains well, 35 months after the biopsy. [Case 2] A 17-year-old boy was found to have a tumor in the anterior mediastinum on chest CT. His serum alpha-fetoprotein level was elevated to 2,461 ng/mL. Histological diagnosis of yolk sac tumor was confirmed using the Chamberlain procedure. He was treated with one course of chemotherapy, followed by surgery; he remains well 57 months after the biopsy. [Case 3] A 72-year-old man was found, on chest X-ray and CT, to have a left upper anterior mediastinal tumor with invasion of the subclavian vessels. The tumor was confirmed histologically as thymic (sarcomatoid) carcinoma using the Chamberlain procedure. Despite 2 courses of chemotherapy, the tumor continued to enlarge and metastasized to the lung and bone. The patient died 7 months after the biopsy. [Case 4] A 62-year-old woman under treatment for rheumatoid arthritis (RA) was found, on a chest X-ray, to have a right anterior mediastinal tumor. Histological diagnosis using the Chamberlain procedure suggested lymphoproliferative disorder, and the RA medication was discontinued. This was followed by a decrease in the tumor size and avoidance of invasive surgery. The patient remains well, 15 months after the biopsy. [Conclusion] The Chamberlain procedure proved useful for definitive diagnosis in all 4 cases of invasive anterior mediastinal tumors. We recommend the Chamberlain procedure for biopsy since it enables safe, rapid, and successful collection of tissue samples.