CASE 2. Thymoma and Tumor Lysis Syndrome in an Adolescent

Angela D. Trobaugh-Lotrario, Xiayuan Liang, Joseph S. Janik, Mark A. Lovell, Lorrie F. Odom

From the Departments of Pediatric Hematology/Oncology, Pathology, and Pediatric Surgery, The Children’s Hospital of Denver; University of Colorado School of Medicine; and University of Colorado Cancer Center, Denver, CO

A 16-year-old previously healthy white male presented with left rib and shoulder pain associated with decreased energy and exercise tolerance, and occasional “blue lips” in cold weather for 2 months. He had no cough, shortness of breath, weight loss, or fever. He denied orthopnea, but slept with two pillows for the last 2 years. Physical examination was remarkable for chest asymmetry, with the left hemithorax appearing more expanded anteriorly, and markedly decreased left-sided aeration. He had no tachypnea or increased work of breathing, and his oxygen saturation in room air was normal. There was no hepatosplenomegaly or lymphadenopathy. Laboratory evaluation disclosed a normal complete blood count, normal creatinine of 0.9 mg/dL, normal serum electrolytes, normal liver enzymes, a high normal lactate dehydrogenase (LDH) of 228 U/L (normal range, 130 to 230), and uric acid of 8.0 mg/dL (normal range, 4 to 8.4). Serum beta-human chorionic gonadotropin and alpha-fetoprotein were normal. Chest radiograph showed nearly complete opacification of the left hemithorax with a large mass and slight mediastinal shift to the right (Fig 1A). On computed tomography scan, the mass was heterogeneous without calcifications, but with multiple pleural metastases (Fig 1B). Echocardiography showed an ejection fraction of 45% and compression of the left pulmonary artery and vein with good dynamic flow. A bone scan was normal, and an octreotide scan subsequently showed uptake within the tumor. He was admitted and underwent a left thoractomy with multiple biopsies and chest tube placement. Grossly, the tumor was partially encapsulated with extensive invasion of surrounding tissue and with multiple pleural implants. He received no steroids intraoperatively. A frozen section of the tumor was interpreted as lymphoblastic lymphoma. On the first postoperative day, he developed emesis and increased chest tube output. That evening, he developed hypotension with blood pressures of approximately 100/40 with oliguria. He received a normal saline bolus, but remained completely oliguric for 12 hours. Serum chemistries showed marked change from baseline: potassium of 5.1 mmol/L, bicarbonate of 17 mmol/L, blood urea nitrogen 67 mg/dL, creatinine of 3.3 mg/dL, ionized calcium of 0.9 mmol/L (normal range, 1.2 to 1.4), LDH 331 U/L, phosphorus of 14 mg/dL, and uric acid of 33.8 mg/dL. Urinalysis had more than 100 RBCs and 10 to 25 WBCs per high power field, and uric acid crystals. A renal ultrasound showed significant focal increased density. He was given calcium, amphojel, allopurinol, and furosemide, and hemodialysis was initiated. CSF and bone marrow aspirate with biopsy were normal. Intrathecal cytarabine was administered. After 3 days of hemodialysis, his phosphorus decreased to 8.9 mg/dL, creatinine was 5.2 mg/dL (after a peak of 6.3), blood urea nitrogen was 59 mg/dL, calcium was 4.2 mEq/L, potassium was 4.1 mmol/L, LDH was 270 U/L, and uric acid was 8.9 mg/dL.

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