Primary renal mucosa-associated lymphoid tissue lymphoma, the result of chronic pyelonephritis?

摘要

Objective: To report 2 cases of primary renal marginal zone B-cell lymphomas of mucosa-associated lymphoid tissue (MALT lymphoma), and observe the relations between this rare tumor of kidney and chronic pyelonephritis. Methods: 2 renal MALT lymphomas were collected from referral consultation. Detailed clinical information were reviewed, morphological analysis based on the HE section, and immunohistochemistry were performed by CD20, CD79a, CD5, CD10, CD43, CD23, BCL10 and Cyclin D1 antibodies. Results: 2 female patients with age of 48 and 55, respectively, all had a history of chronic pyelonephritis. Under the B ultrasonic and CT scanning a bump in the kidney was found. Renal carcinoma suspected and hereby the whole nephrectomy performed. In the macroscopic, tumors were laid in the renal medulla, with dark red color and ill-defined boundary. In the microscopic, there were mixed lymphoid cells infiltrate which mainly consisted of small lympho- cytes, centrocyte-like cells, lymphoplasmacytoid and plasma cells, reactive follicles and lymphoepithelial lesions also could be seen in the lesion, but follicles colonization was rare. In fact, except changes of lymphoma, basic renal disease also could be seen. Most glomeruli were atrophic, some glomeruli were hyperplastic and hypertrophic. Tubules were dilated or contacted, many dilated tubules contained pink-color glassy-appearing casts that suggest the appearance of thyroid tissue. As a result, those 2 cases showed juxtaposed changes of lymphoma and pyelonephritis. Immunohistochemistry showed that tumor cells were CD20 and CD79a positive, CD43 was weak positive, but CD5, CD10, CD23, BCL10 and Cyclin D1 were all negative. Conclusion: Primary renal MALT lymphoma was very rare disease. According to the clinical manifestation, it’s hard to differentiate from renal cell carcinoma. But the morphological features were consistent with the classic MALT lymphomas in other sites. Immunophenotypic profiles were helpful for diagnosis. Based on the truth that many MALT lymphomas in other sites were connected with chronic inflammations, we suppose that the renal MALT lymphoma may originate from chronic pyelonephritis.