title: Interfascicular Renal Cell Carcinoma Metastasis to the Ulnar Nerve: A Case Report.
abstract: BACKGROUND
  Metastatic solid tumors to the hand and peripheral nerves are exceedingly rare independent occurrences. Their occurrence together has never been reported in the literature.
  
  
  METHODS
  We present a case report of a 69 year old male with a previous history of renal cell carcinoma (RCC) presenting with a rapidly-growing painful mass located at the right volar ulnar wrist, found to have endoneural solid tumor metastatic RCC to the ulnar nerve.
  
  
  RESULTS
  Preoperative MRI imaging of the wrist revealed a heterogeneous mass on the volar aspect of the wrist extending along the length of the ulnar artery and nerve to the level of Guyon's canal. Pathologic examination of an incisional biopsy of the mass was consistent with metastatic renal clear cell carcinoma cells, which were infiltrating nerve and surrounding soft tissue. The patient underwent local radiation therapy to the wrist and hand with interval decrease in size of the mass and symptom improvement.
  
  
  CONCLUSIONS
  Solid tumor metastasis, although exceedingly rare, must be considered in the differential diagnosis of a patient with previous cancer history presenting with a wrist or hand mass associated with peripheral neuropathy.
authors.affiliation: University of Chicago, IL, USA.
authors.forename: Laura S
authors.initials: LS
authors.lastname: Humphries
authors.affiliation: Loyola University Chicago, Maywood, IL, USA.
authors.forename: Daniel A
authors.initials: DA
authors.lastname: Baluch
authors.affiliation: Loyola University Chicago, Maywood, IL, USA.
authors.forename: Lukas M
authors.initials: LM
authors.lastname: Nystrom
authors.affiliation: Loyola University Chicago, Maywood, IL, USA.
authors.forename: Dariusz
authors.initials: D
authors.lastname: Borys
authors.affiliation: Loyola University Chicago, Maywood, IL, USA.
authors.forename: Michael S
authors.initials: MS
authors.lastname: Bednar
keywords: hand; peripheral nerve metastasis; renal cell carcinoma