Renal myxoma in a pediatric transplant recipient

Posted By Connor Crowley
Renal myxoma in a pediatric transplant recipient

RENAL MYXOMA IN A PEDIATRIC TRANSPLANT RECIPIENT ABBREVIATIONS CT: Computed tomography CTDIvol: Computed tomography dose index volume DLP: Dose length product MRI: Magnetic Resonance Imaging PET: Positron Emission Tomography POG: Pediatric Oncology group Ki 67: is a protein that is a marker for cellular proliferation HMB-45: Human Melanoma Black-45 is a monoclonal antibody ABSTRACT Renal myxoma is a very rare benign neoplasm seen almost exclusively in adults with only 16 reported cases in the literature. All of these cases have been reported in native kidneys with none being reported in a transplant kidney. We report a case of a renal myxoma in a 17-year old boy in a transplant kidney found as an incidental mass on ultrasonography that was further evaluated with a computed tomography and a positron emission tomography scan. Positron emission tomography findings of renal myxoma are reported here for the first time, and a discussion of imaging findings from previous cases are briefly reviewed. This case report highlights the fact that adult-predominant tumors and pathology should always be a consideration in pediatric patients who receive organ transplants from adult donors. CASE REPORT A 17-year-old boy received a living related donor kidney transplant from his mother at age 2 secondary to congenital renal dysplasia. At the age of 5 years, he was treated for post-transplant lymphoproliferative disorder [PTLD - abdominal stage IV Burkitt’s Lymphoma] per Pediatric Oncology Group (POG) 9317 without complication. At the age of 12 years, the patient developed chronic transplant nephropathy and concomitant renal insufficiency. He received a second kidney transplant at age of 15 years secondary to graft failure of the first transplant and this initial transplant kidney was left in place. The second transplanted kidney was removed 1 week later due to renal vein thrombosis. 6 months later, the patient began hemodialysis and continued to be evaluated for another transplant. He underwent an abdominal ultrasound as part of his pre-transplant work-up and a mass was incidentally discovered in the original transplanted kidney. The ultrasound study showed an enlarged heterogeneous transplant kidney measuring 14.2 cm with a 4.2 x 5.4 x 3.0 centimeter nodular area in the midpole [Fig 1]. A subsequent CT scan was done pre- and post-intravenous contrast (CTDIvol- 20.26 mGy and DLP- 921.70 mGy-cm). The images showed an enlarged transplant kidney with heterogeneous enhancement with a hypodense mass [Fig 2]. Hypodense areas in the inferior portion of the kidney appeared to be infiltrating the kidney and extending into the renal pelvis and proximal ureter [Fig 3a, b]. Initial concern was for recurrence of PTLD, but a PET scan done 2 weeks prior to the ultrasound and CT did not show any hypermetabolic areas [Fig 4 a, b] in the mass. The patient underwent a radical right transplant nephrectomy. The kidney was noted to have a neoplasm in the postero-l

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  • Connor Crowley 2017-03-17 17:03:11

    Here are the figure legends:





    Fig. 1 Longitudinal sonographic image showing a heterogenous enlarged transplant kidney

    Fig. 2 Axial post contrast CT image showing a predominantly hypodense non-enhancing right lower quadrant mass (arrows) distorting the transplant kidney in the posterior aspect

    Fig. 3 Coronal post contrast CT images a Hypodense mass in the medial aspect extending to the renal pelvis (arrows) b Hypodense mass in the medial aspect (arrows) extending from the renal pelvis to the transplant ureter almost to the ureterovesical junction

    Fig. 4 PET-CT images a Axial image showing the mass in the transplant kidney without increased metabolic activity b Coronal image showing the mass in the transplant kidney without increased metabolic activity

    Fig. 5 Gross specimen image showing a well-circumscribed glistening gray tan mass filling the hilum of the kidney (arrows). Dark green substance is remnant of specimen preparation

    Fig. 6 Hematoxylin and eosin stained slide. Original magnification 40X (low power). The tumor is relatively acellular with an abundant slightly basophilic mucoid matrix. Focal areas of more eosinophilic fibrous matrix are also present. Vessels are inconspicuous. The neoplastic cells are spindled or stellate with no mitotic figures. Scattered mononuclear inflammatory cells are seen

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  • Connor Crowley 2017-03-17 16:31:49

    Submitting this case to be considered for invitation to submit a manuscript to JRCR. Thank you all for your feedback.

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