Detection of Alveolar Rhabdomyosarcoma in Pleural Fluid with Immunocytochemistry on Cell Block and Determination of PAX/FKHR Fusion mRNA by Reverse Transcription-Polymerase Chain Reaction
Ruchchadol Sawangpanich MS*, Noppadol Larbcharoensub MD**, Artit Jinawath MD, PhD**, Atcharaporn Pongtippan MD**, Usanarat Anurathapan MD*, Suradej Hongeng MD*
Affiliation : * Department of Pediatric, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok, Thailand ** Department of Pathology, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok, Thailand
Background : Alveolar rhabdomyosarcoma is a primitive malignant round cell neoplasm, which shows skeletal muscle
differentiation. Although their histopathologic and immunohistochemical findings are well known, the cytology,
immunocytochemistry and molecular study on pleural effusion have not been well documented.
Objective : To apply molecular method in the diagnosis and monitoring of alveolar rhabdomyosarcoma.
Case Report : The case of a 14-year-old Thai male, who presented with dyspnea and left pleural effusion. Computed tomography
of the chest and abdomen showed a huge heterogeneous enhancing mass at the left retroperitoneum. Pleural fluid cytology
showed malignant small round blue cells. Immunocytochemical stains on cell block material showed positive reactivity to
vimentin, sarcomeric actin, desmin, MyoD1, myogenin, and CD56 in round cell tumor. Reverse transcription-polymerase
chain reaction (RT-PCR) demonstrated PAX/FKHR fusion transcript. The patient received chemotherapeutic regimen for
advanced-stage rhabdomyosarcoma. Finally, he succumbed to the disease, thirteen months after the diagnosis.
Conclusion : Immunocytochemistry on cell block in conjunction with determination of PAX/FKHR fusion mRNA by RT-PCR
is a molecular method in the diagnosis and monitoring of alveolar rhabdomyosarcoma in pleural fluid.
Keywords : Alveolar rhabdomyosarcoma, Pleural effusion, Cytology, Immunocytochemistry, Reverse transcription-polymerase chain reaction
