Renal infiltration of peripheral T-cell lymphoma, not otherwise specified, mimicking drug-induced acute interstitial nephritis.

Renal invasion of T-cell lymphoma does not usually occur. The renal infiltration of peripheral T-cell lymphoma, not otherwise specified (PTCL-NOS), is rare. Therefore, the detailed pathology, clinical features, and effective therapy of this type of extranodal disease remain uncovered. Here, we report the rare case of acute kidney injury (AKI) caused by the renal infiltration of PTCL-NOS with no evidence of lymphadenopathy and extranodal lesions, except for the kidney. We mistakenly diagnosed our patient with drug-induced acute interstitial nephritis (AIN) at first, because his clinical features were similar to those of drug-induced AIN; however, we reached the correct diagnosis by detecting atypical T-cells in his urine. After the introduction of cyclophosphamide, doxorubicin, vincristine, and prednisone therapy his general condition improved rapidly. When suspecting drug-induced AIN as the cause of AKI, PTCL-NOS should also be recognized as one of the causes, and urine cytology may be useful to noninvasively distinguish between the two diseases.

Atypical familial Mediterranean fever developed in a long-term hemodialysis patient.

Familial Mediterranean Fever (FMF) is usually an autosomal recessive autoinflammatory disease characterized by recurrent attacks of fever and serositis. FMF develops before the age of 20 years in 90% of patients. It has intervals of 1 week to several years between attacks, which leads to renal dysfunction-amyloidosis. We report a case of atypical FMF that developed in a long-term hemodialysis patient. A 65-year-old Japanese female undergoing hemodialysis for 32 years was referred to our hospital with a fever of unknown origin (FUO) following cervical laminoplasty. The fever occurred as recurrent attacks accompanied by oligoarthralgia of the left hip and knee. We suspected FMF because of recurrent self-limited febrile attacks, although the patient showed atypical clinical features such as late-onset and highly frequent attacks. After receiving treatment, she achieved a complete response to colchicine. Therefore, a diagnosis of FMF was made based on the Tel-Hashomer criteria, which was confirmed by genetic testing. The case suggests that FMF may be of note in long-term hemodialysis patients developing FUO.