title: Intravascular lymphomatosis: a case presenting with encephalomyelitis and reactive haemophagocytic syndrome diagnosed by renal biopsy.
abstract: OBJECTIVE
  To report an unusual instance of intravascular lymphomatosis presented with encephalomyelitis and reactive haemophagocytic syndrome. There was no skin involvement. The diagnosis was made on a renal biopsy.
  
  
  RESULTS
  The marrow smear was air dried and stained with Diff-Quik. The tissue sections were stained with haematoxylin and eosin. Masson trichrome, periodic acid-Schiff's reagent, Elastic van Gieson's stain, modified hexamine-silver technique and Martius scarlet blue. Immunohistochemistry for CD45, CD20, CD45RO, Factor VIII related antigen, CD31 and CD34 was performed on paraffin-processed tissue. The marrow smear showed active haemophagocytosis in the histiocytes. The renal biopsy showed intravascular lymphomatosis with tumour cells positive for CD45 and CD20.
  
  
  CONCLUSIONS
  The possibility of intravascular lymphomatosis should be considered in patients with reactive haemophagocytic syndrome where the underlying cause cannot be found after thorough investigation.
authors.affiliation: Department of Pathology, Caritas Medical Centre, Hong Kong.
authors.forename: F Y
authors.initials: FY
authors.lastname: Cheng
authors.forename: W M
authors.initials: WM
authors.lastname: Tsui
authors.forename: W T
authors.initials: WT
authors.lastname: Yeung
authors.forename: L S
authors.initials: LS
authors.lastname: Ip
authors.forename: C S
authors.initials: CS
authors.lastname: Ng
mesh_terms: D000328:Adult; D003937:Diagnosis, Differential; D004679:Encephalomyelitis / Q000175:diagnosis* / Q000473:pathology; D005260:Female; D015616:Histiocytosis, Non-Langerhans-Cell / Q000175:diagnosis* / Q000473:pathology; D006801:Humans; D007680:Kidney Neoplasms / Q000098:blood supply / Q000175:diagnosis* / Q000473:pathology; D016403:Lymphoma, Large B-Cell, Diffuse / Q000175:diagnosis* / Q000473:pathology