We herein report a rare case of primary malignant urethral melanoma developed in an elderly Japanese patient with hypertension, diabetes and hyperlipidemia. An 80-year-old female presented at our hospital with a history of urodynia and perineal pain lasting for several months. Cystoscopy revealed cystitis and urethritis with erosion. At that time, urinary cytology was negative for malignancy, although melanophages were observed. Four months later, lower abdominal computed tomography and magnetic resonance imaging indicated urethral tumors. Urinary cytology subsequently detected malignant melanoma, and a biopsy of the urethra confirmed malignancy. Although inguinal lymph node metastasis was found 16 months postoperatively, the patient has remained free of disease for more than six years after surgery and chemotherapy.

Gene fusions involving two of the MiT subfamily factors, such as TFE3, TFEB, TFC and MiTF, have been identified in renal cell carcinoma (RCC). Xp11.2 translocation RCC is a rare pediatric neoplasm that harbors gene fusions involving TFE3, which plays an important role in cell proliferation and survival. We herein present a case of RCC associated with Xp11.2 translocation/TFE3 gene fusion in a 14-year-old Japanese boy presenting gross hematuria and body weight loss. The tumor was characterized by histopathology, cytology and TFE3-immunohistochemistry/immunocytochemistry. Knowledge of distinctive morphological and immunostaining features of this tumor can help to accurately diagnose this rare subset of translocation associated RCC in routine pathological diagnostic procedures.

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Microscopy can detect the presence of amoebic trophozoites in cerebrospinal fluid and tissue. The infection was confirmed in the present case by polymerase chain reaction and immunohistochemistry, but we were unable to achieve a cure. Our case rapidly progressed without any skin lesions.