Malignant rhabdoid tumors (MRT) of the kidney are rare in children and even less common in adults, with only six previously reported adult cases. We present the case of a 60-year-old man with an MRT arising in the left kidney with extensive pulmonary micrometastases and thromboembolism resulting in thrombotic pulmonary microangiopathy (pulmonary tumor embolism syndrome). MRT is an extremely aggressive neoplasm with a short survival time.M alignant rhabdoid tumor (MRT) of the kidney is a highly aggressive, extremely rare neoplasm that is usually seen in children. Th e term rhabdoid is used because the tumor cells resemble rhabdomyoblasts but lack myogenic markers, and pathologic diagnosis requires familiarity with these microscopic features plus awareness that adult onset is possible. We describe clinical and necropsy fi ndings in an adult with primary renal MRT.
CLINICAL HISTORYA 60-year-old white man with known hypothyroidism, hypertension, and chronic obstructive pulmonary disease had progressive fatigue and abdominal distension for 6 months and worsening dyspnea for 2 weeks. Imaging showed bilateral pulmonary infi ltrates consistent with pneumonia, and he was treated at home with antibiotics and prednisone. Th ree days later, he presented to an outside emergency department with gross hematuria, left calf pain, hemoptysis, painful testicular swelling, and nontraumatic ecchymoses. He was then transferred to Baylor University Medical Center at Dallas and admitted to the intensive care unit. Examination disclosed bilateral lower-extremity edema and ecchymosis over the left calf and ankle. His body mass index was 30.4 kg/m 2 , blood pressure, 170/90 mm Hg; heart rate, 96 beats/minute; respiratory rate, 18 breaths/minute; white blood cell count, 31.9 k/μL; hemoglobin, 9.3 g/dL; hematocrit, 25.9%; platelets, 81 k/μL; prothrombin time, 18.0 seconds (reference range 9.0-12.0 seconds); blood urea nitrogen, 46.0 mg/dL; creatinine, 1.6 mg/dL; and arterial blood gas pH, 7.38. He was given heparin and multiple units of red blood cells and cryoprecipitate. Chest radiograph showed bilateral basilar and right upper lobe infi ltrates. Computed tomography showed a thrombus within the left renal vein that extended into the inferior vena cava and a mass in the mid to lower pole of the left kidney (Figure 1).Over the next few days, the patient's oxygen requirements increased, his abdomen became more distended, and his urine output decreased. A left radical nephrectomy and retroperitoneal lymph node dissection was performed. At surgery, there was no residual thrombus in the left main renal vein. Postoperatively,