Malignant melanoma located in the ureter and gallbladder: A case report and literature review.

RATIONALE:Melanoma is one of a common cutaneous malignancy. Currently, metastatic malignant melanoma is difficult to be diagnosed through imaging examinations. Furthermore, the incidence of metastatic melanoma affecting the gallbladder and ureter is exceptionally rare. PATIENT CONCERNS:A 54-year-old female was admitted to the hospital with a half-month history of left lower back pain. Correlative examination revealed an occupying lesion in the mid-left ureter and the neck of the gallbladder. DIAGNOSES:The patient was initially diagnosed with gallbladder cancer and left ureteral carcinoma based on imaging. Following 2 operations, immunohistochemical staining confirmed the presence of metastatic melanoma involving both the gallbladder and ureter. INTERVENTION:After multidisciplinary consultation and obtaining consent from the patient and her family, the patient underwent left radical nephroureterectomy, radical cholecystectomy, laparoscopic partial hepatectomy (Hep IV, Hep V), and lymph node dissection of hepatoduodenal ligament. OUTCOMES:One month after treatment, the patient imaging showed no disease progression, and at 6 months of follow-up, the patient was still alive. LESSONS:It is difficult to distinguish metastatic melanoma from carcinoma in situ by imaging. In addition, metastatic malignant melanoma lacks specific clinical manifestations and is prone to misdiagnosis, which emphasizes the highly aggressive nature of malignant melanoma.