[Possible contribution of disseminated Mycobacterium shigaense infection to development of splenic marginal zone lymphoma].

A 73-year-old male who underwent splenectomy was diagnosed with splenic non-caseating granuloma in May 201X, and sarcoidosis was disregarded from the differential diagnosis. Owing to the persisting inflammation, the patient was carefully followed up with no treatment. Four months post splenectomy, the patient was hospitalized due to progressive dyspnea. Chest computed tomography revealed an encapsulated pleural effusion and lymphocytic infiltration in the left lower lung, with subclavian and mediastinal lymphadenopathy. Although the patient was treated with antibiotics, his condition showed no improvement; therefore, prednisolone 40 mg was administered, resulting in lung lesion improvement. A re-examination of the tissue obtained from the previously removed spleen revealed splenic marginal zone lymphoma (SMZL), a specific low-grade, small B-cell lymphoma. As a result, the patient was treated with rituximab combined with chemotherapy. During the fifth course of the chemotherapy, a subcutaneous abscess appeared in the cervical region, and Mycobacterium shigaense was isolated from the pus discharge, suggesting that the splenic granulomatous lesion formed due to M.shigaense, and dissemination of the Mycobacterium infection occurred following splenectomy and chemotherapy, when the patient was immunosuppressed. Overall, we consider that SMZL developed because of chronic inflammation resulting from a nontuberculous mycobacterial infection.

Renal artery stenosis following nilotinib administration in a patient with chronic myelogenous leukemia.

A 63-year-old male was diagnosed as having chronic phase CML in 2001. He obtained a major molecular response with imatinib (IM). In 2012, amulodipin was started for hypertension. In January 2013, IM was switched to nilotinib (NIL) in a clinical trial, and in February 2015, NIL was discontinued because MR4.5 had been maintained for two years. One month later, he was admitted to our hospital because of headache and high blood pressure (194/108 mmHg). His urine test showed protein 3+ and occult blood 2+. His eGFR rapidly deteriorated from 45.6 to 28.5 after admission. MR angiography showed left renal artery stenosis. He thus underwent angioplasty of the left renal artery with a stent implantation. His renal function subsequently improved. Cardiovascular events such as PAOD (peripheral artery occlusive disease) during NIL treatment were recently reported. However, to date, only four cases including our present patient with renal artery stenosis associated with NIL have been reported. These observations suggest assessment of risk factors for cardiovascular events at the start of NIL and careful monitoring to be important during tyrosine kinase inhibitor treatment of CML patients.