ASCITES OF THE DIAPHRAGM

Abstract

SESSION TITLE: Medical Student/Resident Pediatrics Posters SESSION TYPE: Med Student/Res Case Rep Postr PRESENTED ON: October 18-21, 2020 INTRODUCTION: Rhabdomyosarcoma is more common in pediatric populations, but remains rare, representing only 3 percent of pediatric cancers. It is typically diagnosed in children less than 6 years of age, and tends to occur in the head and neck, GU tract, and extremities, with different histologic subtypes having a predilection for certain areas. CASE PRESENTATION: We present a 12-year-old girl with 1.5 weeks of cramping upper abdominal pain, nonbilious, abdominal distention, non-bloody emesis, and watery diarrhea. She also reported fatigue and 10 pound weight loss. On presentation, she was afebrile and vitals were within normal limits. Exam was notable for a distended abdomen with positive fluid wave and tenderness in the upper abdomen, as well as inguinal and axillary adenopathy. Initial labs revealed hemoglobin 12.4, platelets 718, AST 48, albumin 2.3, lipase 68. Abdominal ultrasound showed a large amount of ascites. Subsequent labs showed ESR 60, CRP 13.65, LDH 666, and uric acid 6.1. Repeat CT abdomen/pelvis with intravenous and oral contrast showed malignant ascites with focal nodular soft tissue along the left hemidiaphragm as well as in the anterior abdomen, and left pleural effusion. A paracentesis was performed with 3 L of yellow, cloudy fluid obtained with ˜5000 red blood cells, 1120 white blood cells, albumin 2.1, amylase 27, glucose 70, protein 3.9, triglyceride 28. Cytology showed reactive vs neoplastic atypical cells, degenerating cells, reactive mesothelium and inflammatory cells. Quantiferon and AFB cultures were negative. Biopsy of the left hemidiaphragm soft tissue mass showed alveolar infiltrating fibrocollagenous rhabdomyosarcoma. She is currently undergoing palliative radiation and chemotherapy. DISCUSSION: Rhabdomyosarcomas are cancers that originate from rhabdomyoblasts, making them more common in children. There are 4 subtypes: embryonal (59%), alveolar (21%), anaplastic (1%), and undifferentiated (8%). Alveolar rhabdomyosarcomas typically involve large muscles of the trunk and extremities, and tend to occur in individuals ages 10-25. They grow rapidly, and require more intensive therapy. Diagphragmatic rhabdomyosarcomas are rare, with 41 cases noted from 1868 to 2005 in a review of literature. The majority of cases present with thoracic symptoms, rather than abdominal symptoms. A recent study from the Italian Soft Tissue Sarcoma Center identified 150 children over 30 years with rhabdomyosarcoma, with only 18 of those presenting with ascites. CONCLUSIONS: We present a case of alveolar diaphragmatic rhabdomyosarcoma with only 41 cases diagnosed worldwide. What makes this case more rare is the presenting complaint of abdominal symptoms. Our case highlights that these entities can present a diagnostic challenge, given their ability to affect less common areas and grow insidiously until presenting with atypical symptoms. Reference #1: Cada M, et al. Approach to diagnosis and treatment of pediatric primary tumors of the diaphragm. Journal of Pediatric Surgery. October 2006. 41(10):1722-6 Reference #2: Di Carlo, D., Ferrari, A., Toffolutti, T., Milano, G. M., Manzitti, C., Ruggiero, A., ... Bisogno, G. (2019). Prognostic role of pleural effusion or ascites in localized rhabdomyosarcoma. Pediatric Blood and Cancer, 66(11), e27932. https://doi.org/10.1002/pbc.27932 Reference #3: Raney RB, Anderson JR, et al. Soft-tissue sarcomas of the diaphragm: a report from the Intergroup Rhabdomyosarcoma Study Group from 1972 to 1997. Journal of Pediatric Hematology Oncology. 2000 Nov-Dec; 22(6):510-4 DISCLOSURES: No relevant relationships by Holly O'Brien, source=Web Response No relevant relationships by Seif Shahidain, source=Web Response