The American Surgeon | 2019
Anterior Mediastinal Teratoma Secondarily Infected with Salmonella in an Infant
Abstract
Anterior mediastinal tumors classically arise from one of four etiologies: teratomas, thymomas, thyroid masses, and lymphomas. Mediastinal teratomas are typically benign extragonadal germ cell tumors derived from all three embryonic cell layers (ectoderm, mesoderm, and endoderm). Teratomas are categorized as immature or mature based on cell differentiation and malignant potential. The vast majority of teratomas are classified as mature, and these tumors are typically well differentiated and benign in nature. There are very few case reports in the literature describing infected teratomas. We present a rare case of an anterior mediastinal teratoma in an infant presenting with acute respiratory decompensation after becoming secondarily infected with Salmonella. A two-month-old female infant presented to the ED with a five-day history of persistent fevers, decreased oral intake, irritability, and worsening respiratory distress. She had a prenatal diagnosis on ultrasound and MRI of a possible right middle lobe cystic lung lesion. She was delivered via cesarean section at term with no complications at birth. Postnatal chest X-ray revealed an enlarged thymus but no evidence of lung lesion. She was followed up by pediatric surgery at one month of age. She continued to dowell, and repeat chest X-ray showed a persistent enlarged thymus with no evidence of lung lesion. Given these findings, it was recommended that she follow up in one year with a chest CT scan. After presentation to the ED with acute respiratory distress, chest X-ray showed a much larger thymic silhouette than the prior image one month earlier. A CT scan revealed a large anterior mediastinal mass with calcifications, suspicious for teratoma (Fig. 1). She was febrile to 101°F, but her other vitals were within normal limits. On physical examination, she appeared irritable and fretful with rigorous cry. Her cardiac examination was significant for distant heart sounds, and pulmonary examination was significant for decreased breath sounds on the right side. She was tachypneic, grunting, and had notable intercostal and subcostal retractions. Her white blood cell count was normal, but bandemia was present. A full fever workup including lumbar puncture was completed. The respiratory viral panel, blood cultures, and cerebrospinal fluid cultures were negative. Urinalysis showed evidence of urinary tract infection, and urine culture was positive for Proteus mirabilis. The patient was started on ceftriaxone. She was admitted to the ICU for further stabilization, tumor markers were drawn, and she was urgently prepared for surgery. The patient was taken to the operating room for median sternotomy with excision of the mediastinal mass. The lesion, which appeared to have both cystic and solid elements, was adherent to the right anterior thoracic wall, pericardium, and diaphragm. Once dissected free, it measured 10 · 7 cm in size (Fig. 2). Fluid from the pleural cavity was sent for culture. Bilateral chest tubes were placed, and the sternotomy was closed. The patient tolerated the procedure well. The surgical pathology report revealed a mature teratoma, and the intraoperative culture grew Salmonella. The patient was appropriately treated with a full seven-day course of ceftriaxone. The patient’s postoperative course was uneventful. Her right chest tube was discontinued on postoperative day 4, and the left chest tube was discontinued on postoperative day 5. She was discharged home in good condition on postoperative day 6. One month later, the patient continues to do well at surgical follow-up and is having no issues. Germ cell tumors represent up to 24 per cent of mediastinal neoplasms, and there are four types: mature teratomas, immature teratomas, seminomas, and nonseminomatous germ cell tumors. Mature teratomas are slow-growing and benign, and they usually arise in the anterior mediastinum, either near the thymus or from within the thymic parenchyma. The other three types of mediastinal germ cell tumors are either malignant or have high rates of malignant conversion.1 Address correspondence and reprint requests to Richard M. Tanner Jr., M.D., Department of Surgery, University of Tennessee College of Medicine Chattanooga, 979 East Third Street, Suite B-401, Chattanooga, TN 37403. E-mail: Richard.tanner.jr@gmail. com.