title: Isolated omental metastasis of renal cell carcinoma after extraperitoneal open partial nephrectomy: A case report.
abstract: BACKGROUND
  Metachronous metastatic spread of clinically localized renal cell carcinoma (RCC) affects almost 1/3 of the patients. They occur most frequently in lung, liver, bone and brain. Isolated omental metastasis of RCC has not been reported so far.
  
  
  METHODS
  A 62-year-old patient previously diagnosed and treated due to pulmonary sarcoidosis has developed an omental metastatic lesion 13 years after having undergone open extraperitoneal partial nephrectomy for T1 clear-cell RCC. Constitutional symptoms and imaging findings that were attributed to the presence of a sarcomatoid paraneoplastic syndrome triggered by the development this metastatic focus complicated the diagnostic work-up. Biopsy of the [18F]-fluorodeoxyglucose (+) lesions confirmed the diagnosis of metastatic RCC and the patient was managed by the resection of the omental mass via near-total omentectomy followed by targeted therapy with a tyrosine kinase inhibitor.
  
  
  CONCLUSIONS
  Late recurrence of RCC has been reported to occur in 10-20% of the patients within 20 years. Therefore lifelong follow up of RCC has been advocated by some authors. Diffuse peritoneal metastases have been reported in certain RCC subtypes with adverse histopathological features. However, isolated omental metastasis without any sign of peritoneal involvement is an extremely rare condition.
  
  
  CONCLUSIONS
  To our knowledge, this is the first reported case of metachronously developed, isolated omental metastasis of an initially T1 clear-cell RCC. Constitutional symptoms, despite a long interval since nephrectomy, should raise the possibility of a paraneoplastic syndrome being associated with metastatic RCC. Morphological and molecular imaging studies together with histopathological documentation will be diagnostic.
authors.affiliation: Koc University, School of Medicine, Department of Urology, Istanbul, Turkey.
authors.forename: Ömer
authors.initials: Ö
authors.lastname: Acar
authors.affiliation: VKF American Hospital, Department of Urology, Istanbul, Turkey. Electronic address: tunam@amerikanhastanesi.org.
authors.forename: Tuna
authors.initials: T
authors.lastname: Mut
authors.affiliation: Acibadem University, School of Medicine, Department of Pathology, Istanbul, Turkey.
authors.forename: Yeşim
authors.initials: Y
authors.lastname: Sağlıcan
authors.affiliation: Koc University, School of Medicine, Department of Radiology, Division of Interventional Radiology, Istanbul, Turkey.
authors.forename: Alan Alper
authors.initials: AA
authors.lastname: Sag
authors.affiliation: Koc University, School of Medicine, Department of Nuclear Medicine and Molecular Imaging, Istanbul, Turkey.
authors.forename: Okan
authors.initials: O
authors.lastname: Falay
authors.affiliation: Koc University, School of Medicine, Department of Internal Medicine, Division of Medical Oncology, Istanbul, Turkey.
authors.forename: Fatih
authors.initials: F
authors.lastname: Selcukbiricik
authors.affiliation: Koc University, School of Medicine, Department of Internal Medicine, Division of Pulmonary Medicine, Istanbul, Turkey.
authors.forename: Levent
authors.initials: L
authors.lastname: Tabak
authors.affiliation: Koc University, School of Medicine, Department of Urology, Istanbul, Turkey; VKF American Hospital, Department of Urology, Istanbul, Turkey.
authors.forename: Tarık
authors.initials: T
authors.lastname: Esen
keywords: Case report; Metastasis; Omentum; Renal cell carcinoma