Lymphomas and lymphoproliferative disorders clinically presenting as renal carcinoma: A clinicopathological study of 14 cases

Aims: Although uncommon, lymphomas and lympho-proliferative disorders (LPDs) that manifest as renal or peri-renal masses can mimic primary renal cancers upon clinical and radiological evaluations. However, such distinction is critical as the management of these diseases are drastically different. This study reports the clinical, radiological and pathological features of 14 lymphomas/LPDs that were initially managed as primary renal carcinomas. Methods: The surgical pathology file was queried for kidney resections or biopsies with a diagnosis of lymphoma or LPD. The clinical symptomatology, imaging results, pathology data, treatment regimens and outcome data were obtained by electronic patient data search and/or chart review. Results: Lymphomas/LPDs accounted for only 29 of 5490 (0.5%) of renal neoplasms diagnosed by pathology over a 27 year period. Of these 29 cases, 14 had a presumptive clinical diagnosis of renal carcinoma prior to nephrectomy or biopsy. Eleven of 14 (78.6%) had concurrent retroperitoneal, periaortic or distant adenopathy. Only two cases had inferior vena caval invasion. On pathological examination, the majority of these cases were mature B-cell neoplasms; however, three of 14 cases were initially interpreted as poorly differentiated carcinoma on routine histological sections. Upon staging, all 14 cases had nodal and/or additional extranodal involvement while only two of 14 cases demonstrated vascular invasion. Conclusions: Lymphomas/LPDs should always be kept in the differential diagnosis for unusual renal or perirenal masses. Extensive regional or distant adenopathy without vascular invasion favours a clinical diagnosis of LPD, while the presence of both regional adenopathy and vascular invasion should raise clinical suspicion for renal carcinoma.