title: Acute lymphoblastic leukemia mimicking Wilms tumor at presentation.
abstract: BACKGROUND
  Acute lymphoblastic leukemia (ALL), the commonest malignancy of childhood, is known to manifest with a myriad of atypical presentations. Nephromegaly is a rare presentation of childhood ALL with hepatic mass being even rarer.
  
  
  METHODS
  We present a 3 year-old child with unilateral renal mass and hepatic mass lesion with normal blood counts, initially suspected to have metastatic Wilms tumor based on clinical, radiological and WT1 positivity on immunocytochemistry of renal mass. He was later diagnosed as ALL with peripheral blood flowcytometry and bone marrow examination.
  
  
  CONCLUSIONS
  Renomegaly at presentation of acute leukemia is not necessarily due to leukemic infiltration and rarely leads to renal impairment. The radiological differential of such a renal mass includes both benign and malignant entities including metastasis. Over-expression of WT1 mRNA has been found in a number of solid tumors and hematological malignancies and is far from being diagnostic of Wilms tumor. Again, a small number of children with acute leukemia may have a deceptively normal complete blood count at presentation. Though, initial all (clinical, radiological, hematological, and immunocytological) parameters pointed towards a diagnosis of Wilms tumor in our case, the subsequent development of thrombocytopenia and lymphocytic leukocytosis prompted further investigation and final diagnosis of ALL.
  
  
  CONCLUSIONS
  WT1 positivity is a known phenomenon in childhood ALL and undifferentiated lymphoblasts may be positive for WT1 and negative for Leucocyte common antigen. Acute leukemia with renal and hepatic mass with normal blood counts at presentation is a diagnostic challenge.
authors.affiliation: Department of Pediatrics, Chacha Nehru Bal Chikitsalaya, Geeta Colony, New Delhi.
authors.forename: Amitabh
authors.initials: A
authors.lastname: Singh
authors.affiliation: Department of Pediatrics, All India Institute of Medical Sciences, Ansari Nagar, New Delhi.
authors.forename: Anirban
authors.initials: A
authors.lastname: Mandal
authors.affiliation: Department of Pediatrics, All India Institute of Medical Sciences, Ansari Nagar, New Delhi.
authors.forename: Vijay
authors.initials: V
authors.lastname: Guru
authors.affiliation: Department of Pediatrics, All India Institute of Medical Sciences, Ansari Nagar, New Delhi.
authors.forename: Rachna
authors.initials: R
authors.lastname: Seth
mesh_terms: D002675:Child, Preschool; D003937:Diagnosis, Differential; D006801:Humans; D015470:Leukemia, Myeloid, Acute / Q000175:diagnosis*; D008297:Male; D054198:Precursor Cell Lymphoblastic Leukemia-Lymphoma; D012333:RNA, Messenger; D025721:WT1 Proteins / Q000378:metabolism; D009396:Wilms Tumor / Q000175:diagnosis*
chemical_list: D012333:RNA, Messenger; D025721:WT1 Proteins