SESSION TITLE: Fellows Imaging Posters SESSION TYPE: Fellow Case Report Posters PRESENTED ON: October 18-21, 2020 INTRODUCTION: Halo sign on chest imaging is characterized by a circular area of ground-glass attenuation around a central pulmonary nodule or mass. It is most commonly associated with invasive fungal infections; however, can also be seen in a wide range of neoplastic and inflammatory conditions. Here we present a case of angio-invasive neoplasm presenting with characteristic halo sign in an immunocompromised patient. CASE PRESENTATION: A 62-year-old male with alcoholic cirrhosis post orthotopic liver transplant on chronic immunosuppression with recurrent cirrhosis of his graft liver was initially admitted for management of acute hepatic encephalopathy. A CT scan of his chest showed numerous part solid centrilobular nodules bilaterally with central solid component and surrounding ground glass halo. Invasive fungal infection was suspected, and micafungin was initiated. Serum aspergillus antigen and beta D-glucan were negative. He underwent bronchoscopy with bronchoalveolar lavage (BAL) and transbronchial biopsy (TBB). BAL was negative for bacterial, fungal and acid-fast bacilli cultures. Pathology from the TBB showed atypical epithelioid cells that could be reactive or due to a metastatic disease. A repeat CT scan performed after 10 days of antifungal therapy showed a significant increase in size of the previously noted centrilobular nodules with surrounding ground glass halo. Surgical open lung biopsy was considered but he was deemed to be a poor surgical candidate due to his frailty and comorbidities. Transbronchial cryobiopsy was then performed which showed poorly differentiated epithelioid neoplasm predominantly within the vascular spaces. Based on immunohistochemical staining positive for both cytokeratin and vascular markers, a differential diagnosis of epithelioid angiosarcoma vs. epithelioid sarcoma was made. After detailed discussion with him and his family in regards to his overall prognosis, he wished for no further testing or interventions and chose to go home with hospice. DISCUSSION: Halo sign indicates presence of hemorrhagic nodules. It was first described in immunocompromised patients with invasive pulmonary aspergillosis where the nodule itself is a focus of pulmonary infarction with surrounding alveolar hemorrhage. However, it has now been associated with a variety of pulmonary diseases including both infectious and non-infectious hemorrhagic nodules, tumor cell infiltration and few non-hemorrhagic etiologies. Metastatic lung disease from hyper vascular tumors such as angiosarcoma, chondrosarcoma and melanoma can form a halo of ground glass attenuation as a result of peritumoral hemorrhage or infiltration. Malignancy is a leading cause of death in post liver transplant patients and should always be considered in the evaluation of these patients. CONCLUSIONS: While evaluating halo sign a wide differential should be considered including malignancy in a post liver transplant patient. Reference #1: Georgiadou SP, Sipsas NV, Marom EM, Kontoyiannis DP. The diagnostic value of halo and reversed halo signs for invasive mold infections in compromised hosts. Clin Infect Dis. 2011;52(9):1144-1155. doi:10.1093/cid/cir122 Reference #2: Parrón M, Torres I, Pardo M, Morales C, Navarro M, Martínez-Schmizcraft M. Signo del halo en la tomografía computarizada de tórax: diagnóstico diferencial con correlación anatomopatológica [The halo sign in computed tomography images: differential diagnosis and correlation with pathology findings]. Arch Bronconeumol. 2008;44(7):386-392. DISCLOSURES: No relevant relationships by Sadia Benzaquen, source=Web Response No relevant relationships by Ena Gupta, source=Web Response No relevant relationships by ATUL MATTA, source=Web Response No relevant relationships by Corrado Minimo, source=Web Response No relevant relationships by Carlos Oberto, source=Web Response
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