Presentation
Abdominal pain and bloody diarrhea for 2 days. Clinical suspicion of ischemic colitis.
Patient Data
Findings: Extensive atherosclerotic changes are seen in the abdominal aorta; however, no bowel ischemia is seen. Marked circumferential thickening and pericolonic fat stranding is noted in the proximal transverse colon adjacent to the hepatic flexure; however, no definite colonic diverticula are seen in this region. No free fluid or collection/abscess is appreciable around the transverse colon. No pneumoperitoneum is seen. Multiple diverticula are seen in the distal descending and sigmoid colon without any inflammatory changes in the surrounding mesentery. Dilated CBD measuring 14 mm which is traceable almost throughout its course; no filling defect is seen in it. No obvious focal lesion is seen in the pancreas. No radiopaque gallstones or intrahepatic biliary dilatation is seen. An ill-defined poorly enhancing lesion is seen in the renal medulla at the upper pole of the left kidney. A few para-aortic and aortocaval lymph nodes are seen; the largest para-aortic lymph node seen at the level of left renal hilum measures 10 mm in short axis. A few simple cortical cysts are seen in the kidneys. Decreased bone density and degenerative changes are seen in the spine.
Impression: Distal colonic diverticulosis. Marked circumferential thickening and pericolonic fat stranding in the proximal transverse colon; infective colitis?
Findings: Enlarged left kidney with an ill-defined infiltrative poorly enhancing soft tissue mass lesion, which has dramatically increased in its size as compared to the previous scan. No renal vein or IVC thrombosis is seen. An interval increase is also noted in the left para-aortic and aortocaval lymphadenopathy. A few small subcentimeter bilateral iliac lymph nodes are also noted. The right kidney is normal. Average size spleen with multiple small hypodense non-enhancing lesions. Re-demonstration of dilated CBD and distal colonic diverticulosis. Mild bilateral pleural effusions. Minimal free fluid in the abdomen and pelvis. Impression: Left renal mass lesion with enlarged retroperitoneal lymphadenopathy and multiple small focal splenic lesions; the prime diagnostic consideration should be lymphomatous infiltration of the kidney and spleen. Possibility of other neoplastic lesion, like RCC is unlikely.
Bulky/enlarged left kidney with heterogeneous parenchymal echogenicity. An infiltrative lesion is seen at its upper and mid poles. Mild internal vascularity is seen in it on color Doppler ultrasound examination.
Left renal mass biopsy was done by the radiologist under ultrasound guidance, without any complications.
Procedure: Ultrasound-guided left renal biopsy. Microscopy: There are scattered large cells with irregular nuclear membranes and prominent/large frequently eosinophilic nucleoli. These large cells show binucleation or multinucleation and resemble Reed-Sternberg cells, and Hodgkin cells. The surrounding cells show epithelioid histiocytes, lymphocytes and a few plasma cells. Areas of necrosis are also noted. Immunohistochemical stains revealed that the neoplastic cells are immunoreactive to Vimentin, CD15 and CD30. There are numerous CD3 positive cells. A few scattered CD79a positive cells are also noted. The large cells are negative for cytokeratin AE1/AE3. The atypical cells with Reed-Sternberg-like or Hodgkin-like morphology are immunoreactive to CD30 and some of them to CD15. Immunoreactivity for cytomegalovirus is negative. EBV immunohistochemistry shows that there are several atypical cells with immunoreactivity. The overall morphology as well as immunohistochemical pattern is of "Malignant renal lymphoma, favoring, Hodgkin-type". Although, there are features suggestive of Hodgkin lymphoma; however, this is an extranodal location and a very rare site to be involved by this lymphoma. Therefore, additional biopsy of a peripheral lymph node is recommended if the patient has peripheral lymphadenopathy.
Because of her age and other medical comorbidities, the left renal lesion was not further investigated initially; however, it was biopsied after the 2nd CT scan one year later to differentiate between primary versus secondary renal malignancy. The pathologist's recommendation of peripheral lymph node biopsy could not be followed because of absence of peripheral lymphadenopathy. The patient died three weeks later without any further investigations.
Case Discussion
Primary renal lymphoma is a rare clinical entity. The genitourinary system (with kidneys being the most commonly affected) is the second most frequently affected system by the extranodal spread of lymphoma (known as secondary renal lymphoma), after the hematopoietic and reticuloendothelial system 1. Most of these secondary renal lymphomas are B-cell type non-Hodgkin lymphomas. The gold standard of diagnosis of the primary renal lymphoma (PRL) is histopathological diagnosis proven with a renal biopsy 2. Radiological features of the PRL are analogous to the secondary renal lymphoma 2.