Pulmonary alveolar proteinosis in pediatric leukemia.
BACKGROUND
Pulmonary alveolar proteinosis (PAP) is a rare disorder characterized by intra-alveolar accumulation of periodic acid-Schiff (PAS)-positive surfactant components. Leukemia is the cancer most often associated with PAP; prolonged neutropenia and reduction of alveolar macrophages by myeloablative chemotherapy or leukemic infiltration are implicated. Only isolated cases of PAP have been reported, and pediatric experience is limited.


METHODS
We reviewed all pathology records (1962-2007) of St. Jude Children's Research Hospital to identify patients with PAP.


RESULTS
Five patients had PAP. As expected, all had leukemia and had profound neutropenia at onset of PAP. A diagnosis was made only after PAS staining of bronchoalveolar lavage (BAL), lung biopsy, or autopsy specimens. Two patients had Down syndrome, which is not known to be associated with PAP. The other three patients had undergone hematopoietic stem cell transplantation (HSCT). Two patients showed clinical improvement or histological disappearance of PAP after neutropenia resolved.


CONCLUSIONS
PAP should be considered in the differential diagnosis of severe respiratory symptoms in neutropenic patients with hematologic malignancy, especially those with Down syndrome, a history of HSCT, or active disease. PAP should be confirmed by PAS staining of a BAL or lung biopsy specimen.
Inaba
Hiroto
H
Department of Oncology, St. Jude Children's Research Hospital, Memphis, Tennessee, USA. hiroto.inaba@stjude.org
Jenkins
Jesse J
JJ
McCarville
M Beth
MB
Morrison
R Ray
RR
Howard
Scott C
SC
Pui
Ching-Hon
CH
Ribeiro
Raul C
RC
D000293:Adolescent; D000328:Adult; D001706:Biopsy; D018893:Bronchoalveolar Lavage; D002675:Child, Preschool; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007938:Leukemia / Q000150:complications*; D008297:Male; D009503:Neutropenia; D011649:Pulmonary Alveolar Proteinosis / Q000175:diagnosis* / Q000209:etiology; D012189:Retrospective Studies; D013194:Staining and Labeling