title: Large mass affecting retroperitoneal great vessels: a rare presentation of a cancer of unknown primary with diagnostic dilemma and challenged surgical intervention.
abstract: BACKGROUND
  Cancers of unknown primary site (CUPs) consist of a clinical entity which accounts for 3-5% of all solid tumor patients. They are metastatic solid tumors whose fundamental characteristic is the absence of identifiable site of the primary tumor.
  
  
  METHODS
  We report the case of a completely asymptomatic 34-year-old man with a palpated huge mass found incidentally in the left abdomen. All the investigations were normal. During the operation, a large mass was identified 2 cm below the left renal artery which was displacing and encompassing the great retroperitoneal vessels and the left ureter. A complete resection of the mass was performed while the histological examination revealed a solitary retroperitoneal lymph node categorized as metastatic adenocarcinoma of unknown primary site.
  
  
  CONCLUSIONS
  It is essential to assess the high incidence of patients with cancer who present with CUP. Early surgical excision of the metastatic lesion followed by adjuvant combination chemotherapy should be considered for patients with only a single site of malignancy.
authors.affiliation: Oncology Department, 401 General Army Hospital of Athens, Athens, Greece.
authors.forename: Paraskevi
authors.initials: P
authors.lastname: Stakia
authors.forename: Panagiotis
authors.initials: P
authors.lastname: Lagos
authors.forename: Stavros
authors.initials: S
authors.lastname: Gourgiotis
authors.forename: Vasilios D
authors.initials: VD
authors.lastname: Tzilalis
authors.forename: Stavros
authors.initials: S
authors.lastname: Aloizos
authors.forename: Nikolaos S
authors.initials: NS
authors.lastname: Salemis
mesh_terms: D000230:Adenocarcinoma / Q000556:secondary* / Q000628:therapy; D000328:Adult; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use; D001808:Blood Vessels / Q000473:pathology*; D003131:Combined Modality Therapy; D006801:Humans; D033162:Incidental Findings; D008207:Lymphatic Metastasis / Q000473:pathology; D008297:Male; D009382:Neoplasms, Unknown Primary / Q000473:pathology* / Q000628:therapy; D012186:Retroperitoneal Neoplasms / Q000556:secondary* / Q000628:therapy; D014057:Tomography, X-Ray Computed