title: Pleural relapse during hematopoietic remission in childhood acute lymphoblastic leukemia.
abstract: OBJECTIVE
  This report describes an isolated pleural relapse during hematopoietic remission in a child previously treated for acute lymphoblastic leukemia (ALL).
  
  
  METHODS
  An 11-year-old boy had a cough and exertional dyspnea 34 months after an initial diagnosis of ALL and 10 months after completion of therapy. Imaging studies revealed a large left pleural effusion. Bone marrow and cerebrospinal fluid studies were negative for disease at this time.
  
  
  RESULTS
  Histopathologic examination of biopsy samples revealed cells with morphologic features of acute lymphoblastic leukemia blasts. Immunophenotyping, cytogenetic, and gene rearrangement studies confirmed the presence of a leukemic blast cell population similar to that detected at initial diagnosis. An isolated extramedullary relapse in the pleura was diagnosed. The patient underwent successful reinduction therapy and subsequently a matched unrelated donor bone marrow transplant; he died of disseminated infection in the posttransplant period.
  
  
  CONCLUSIONS
  Unusual extramedullary sites of relapse are recognized with increasing frequency as long-term survival in childhood ALL improves. The length of the disease-free interval before relapse is felt to be of prognostic significance. Isolated relapse to the pleural space has not previously been described. The mechanism for persistence of leukemic clones in patients who appear to be in hematopoietic remission is unknown.
authors.affiliation: Department of Pediatrics, British Columbia's Children's Hospital, Vancouver, Canada.
authors.forename: D B
authors.initials: DB
authors.lastname: Dix
authors.forename: R A
authors.initials: RA
authors.lastname: Anderson
authors.forename: D E
authors.initials: DE
authors.lastname: McFadden
authors.forename: L D
authors.initials: LD
authors.lastname: Wadsworth
mesh_terms: D000328:Adult; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use; D001752:Blast Crisis; D001853:Bone Marrow / Q000473:pathology; D016026:Bone Marrow Transplantation; D017809:Fatal Outcome; D015321:Gene Rearrangement; D006410:Hematopoiesis; D006801:Humans; D016130:Immunophenotyping; D007621:Karyotyping; D008297:Male; D016066:Pleural Effusion, Malignant / Q000175:diagnosis* / Q000628:therapy; D054198:Precursor Cell Lymphoblastic Leukemia-Lymphoma / Q000473:pathology* / Q000628:therapy*; D012008:Recurrence; D013997:Time Factors