Results: CT Clinical Practice: Interpretation

Renal masses

1. Can multiple bilateral renal angiomyolipomas be distinguished from extramedullary hematopoeisis on CT or by any other imaging? How common are multiple, bilateral lesions absent TS or LAM?

Answer: In the absence of tuberous sclerosis, most renal AML's are solitary. They can always be distinguished from extramedullary hematopoeisis (EH) as AMLs contain various amounts of fat, while EH does not. Also, EH occurs typically in the pararenal space, not the kidney parenchyma.

2. What do you do with the cyst identified on noncontrast CT for stone study? Do you recommend US or contrast study or presume benign cyst if it looks like a cyst? Does patient age, lesion size (< 1 cm, 1-2 cm, > 2cm) or body habitus/weight influence which imaging modality to use? (This question submitted by 2 individuals.)

Answer: If it looks like a cyst, I consider it a cyst and stop there.

3. We are using a Volume Zoom MDCT scanner. We did a CT in a patient with left renal pathology, most probably not RCC. Pelvic fat is not visible, encased with soft tissue without strict border (not typical for urothelial carcinoma), parenchymal opacification is significantly decreased compared to the right side. Excretion is delayed and decreased. We are considering urothelial carcinoma or chronic pyelonephritis. Urine leukocyte count is normal. Can you help us with the diagnosis?

Answer: Sounds like transitional cell carcinoma. Send me the images and I will happily take a look.

References


Georgiades CS, Neyman EG, Francis IR, Sneider MB, and Fishman EK. Typical and Atypical Presentations of Extramedullary Hematopoiesis AJR 2002; 179: 1239 - 1243.

  • Summary: Included in this review article is a discussion of the appearance of extramedullary hematopoeisis in the kidney region, which typically arises in the parapelvic or perinephric regions.

Sharma AK Tumefactive extramedullary hematopoiesis of the kidney in a patient with idiopathic thrombocytopenic purpura AJR 1996; 167: 795 - 796.

  • Summary: In this case report, a woman with ITP underwent sonography and CT, which revealed a mass replacing the majority of her left kidney. In addition, hepatosplenomegaly was noted. Biopsy revealed intrarenal extramedullary hematopoeisis (EMH). The authors note that EMH simulating renal cell carcinoma is rare.

Kim JK, Park S-Y, Shon J-H, Cho K-S. Angiomyolipoma with minimal fat: Differentiation from renal cell carcinoma at biphasic helical CT. Radiology 2004; 230: 677-684.

  • Summary: This study compared 81 patients with angiomyolipomas (AML) that contained minimal fat, to 62 patients with renal cell carcinoma (RCC), using unenhanced, corticomedullary and excretory phase acquisitions. Results showed that homogeneous enhancement (79% vs. 5%) and prolonged enhancement (58% vs. 10%) were more common in AML than RCC, respectively.

Rha SE, Byun J-Y, Jung SE et al. The Renal Sinus: Pathologic Spectrum and Multimodality Imaging Approach RadioGraphics 2004; 24: 117-131.

  • Summary: This review describes the anatomy and pathology of the renal sinus, including a wide variety of disease processes and the imaging features using various modalities. This article provides CME credit.