Primary malignant Melanoma of the kidney: a rare case report
Tsung-Hsien Wu、Yuantso Cheng
Department of Urology, Kaohsiung Chang Gung Memorial Hospital, Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Kaohsiung, Taiwan
Metastasis malignant melanomas of kidney is common noted in patients. These lesions are usually multiple, asymptomatic, small and bilateral. We report a case of malignant melanoma presenting as a renal pelvis mass that was found by abdominal CT, and confirmed by surgical and pathologic examination. The patient has been living tumor free for 2 years and 3 months after surgery. We preferred that this is a primary malignant melanoma of the kidney.
This is a 77 years old patient with underlying disease of 1.hypertention, 2.diabetes mellitus, 3.stone history. This time, he complained pf right lower abdomen pain with intermittent fever for one week. He had visited OPD and sonography showed Right hydronephrosis and hydroureter. Then, he came to our OPD where enhanced abdominal CT showed right upper ureter lesion. After discussed with the patient, right hand assisted retroperitoneal nephrouretrectomy was arranged. However, pathology showed Malignant melanoma and immunohistochemical stain showed CK7: (-), GATA3: (-)SOX10: (+), Melan-A: Focal (+), HMB45: Focal (+), S100: Focal (+). He went to dermatology OPD but physical examination showed no overt skin lesion. Therefore, this is a case report of primary malignant Melanoma of the kidney.
Malignant melanoma is a tumor that can grow in any organ, but primary malignant melanoma of the urinary tract is extremely rare. Clinically, malignant melanoma with ureteral involvement can present by hydronephrosis or filling defects seen on echography or abdominal CT which mimicking renal cell carcinoma or urothelial carcinoma. In our case, renal mass lesion cannot detect by echography, but renal pelvis solid, irregular, unilateral mass was noted. Acording to Stein and Kendall, a primary melanoma could not be located because the primary lesion had probably regressed. Birkhoff et al. also reported that melanin-synthesizing cells was not noted at the kidney. However, the physical examination by dermatologist cannot detect any pigmented or overt skin lesion. In our case, the immunohistochemical stain showed SOX10, Melan-A, HMB45, S100 which demonstrated a malignant melanoma. Gakis et al. had proposed a therapeutic treatment algorithm. If the lesions was unilateral involvement, a nephroureterectomy with regional lymphadenectomy was suggested. Adjuvant chemotherapy with dacarbazine was indicated if the pathology results demonstrated positive margins or positive lymph nodes. In this case,the pathology kidney showed a solid pelvic tumor infiltrating to the peripelvic fat, the ureter and bladder cuff are free of tumor involvement, also margin clear. The case was regular followed up at our OPD and dermatology OPD currently.