Prevalence and patterns of renal involvement in imaging of malignant lymphoproliferative diseases

Autopsy data on 1,206 children and adult patients with acute myelocytic leukemia (AML) (585), chronic granulocytic leukemia (CGL) (204), acute lymphocytic leukemia (ALL) (308), and chronic lymphocytic leukemia (CLL) (109) obtained from 1958 to 1982 were reviewed. This analysis has shown that, whereas the proportion of patients with residual AML at any anatomic site decreased significantly and uniformly over the entire study period, significant corresponding decreases in patients with CGL and ALL occurred only since 1976 and 1978, respectively. No significant corresponding decreases were noted in patients with CLL at any time. Significant decreases were also noted over time in the rates of extramedullary site involvement by AML, CGL, and ALL. Whereas the lymphoreticular organs, kidneys, adrenals, and pituitary were most often involved at autopsy by CLL, the testes, leptomeninges, dura mater, uterus, large bowel, and pancreas were most often involved by ALL. In general, patients with AML and CGL showed the lowest relative rates of involvement of the various organs by leukemia during the 24-year period. Whereas patients with AML and ALL showed significant decreases in the rates of involvement of nearly all anatomic sites during the most recent study periods, those with CGL and CLL showed corresponding decreases in only a few organ sites. The lower rates of organ involvement in patients with AML and ALL attest to the more aggressive eradication of leukemic cells by therapeutic regimens in these diseases over time. In particular, the significant decrease in the rate of meningeal involvement by ALL during the most recent period is probably attributable to central nervous system prophylaxis.

Extranodal spread of lymphoma often affects the genitourinary system, with the kidneys being the most commonly involved organs. Contrast material-enhanced computed tomography (CT) remains the modality of choice for the detection, diagnosis, staging, and monitoring of renal lymphoma. Magnetic resonance (MR) imaging is particularly useful in patients in whom intravenous administration of iodinated contrast material is contraindicated. Ultrasonography (US), although very valuable for diagnosing lymphoma in the testis or epididymis, is less sensitive than CT and MR imaging for detecting renal lymphoma. Typical imaging findings of renal lymphoma include multiple poorly enhancing or hypoechoic masses, retroperitoneal tumors directly invading the kidneys, bilateral renal enlargement, and perirenal soft-tissue masses. Cystic lesions and tumors predominantly affecting the renal sinus and collecting system are uncommon. Unless the renal lesions manifest in the setting of widespread lymphoma, percutaneous biopsy is indicated to differentiate lymphoma from metastases, hypovascular renal cell carcinoma, uroepithelial carcinoma, or atypical infection, with US routinely being used to guide the procedure. Current immunohistochemical techniques allow accurate diagnosis and characterization of renal lymphoma. Radiologists should be familiar with both typical and atypical manifestations of renal lymphoma and should recommend imaging-guided percutaneous biopsy for diagnostic confirmation to avoid unnecessary nephrectomy. Copyright RSNA, 2006