A80-3-17 Atypical Presentation of Primary Pulmonary Angiosarcoma Effusion: A Diagnostic Conundrum

Abstract Pulmonary epitheloid angiosarcoma (PEAS) is an extremely rare and aggressive malignancy with only about 40 cases reported in the literature. It is typically misdiagnosed due to its rarity, nonspecific clinical presentation, and variable radiographic findings. We report a case of PEAS emphasizing the diagnostic dilemma presenting with recurrent hemorrhagic pleural effusions. A 71-year-old male with a medical history of hypertension and fiberglass occupational exposure presented with progressive dyspnea and dizziness one week following discharge for community-acquired pneumonia. He denied any history of falls, trauma, or use of anticoagulants. The laboratory investigations revealed a 2.4 mg/dl hemoglobin drop. A chest CT scan revealed a new large right-sided pleural effusion, along with tiny solid pulmonary nodules bilaterally measuring up to 6.7 mm, as well as mediastinal and hilar lymphadenopathy. Around 2.2 L of serosanguineous fluid was drained, which reported negative infectious and cytopathology studies. Despite initial improvement, the patient presented twice following discharge. Initially he underwent chest tube placement. A CT chest post chest tube insertion revealed ground glass opacities in the right lung base. Following that, due to loculated pleural effusion and persistent serosanguinous pleural drainage, he underwent video-assisted thoracoscopy with wedge resection, which confirmed epitheloid angiosarcoma involving visceral pleura, lung parenchyma, and extensive lymphovascular invasion with positive immunochemistry for pancytokeratin, vimentin, IMP3, CD31, and ERG. A PET scan (image) confirmed primarily lung and pleural involvement with metastasis to bone. The patient was referred to oncology for palliative treatment. PEAS represents 0.001% of all lung cancers that typically present with non-specific symptoms such as cough, dyspnea, and hemoptysis. Massive and spontaneous hemothorax has been reported in some cases as challenging presentation given its close proximity to the pleura. Recurrent hemothorax may be explained on similar grounds, although less typical and often results in misdiagnosis or delayed diagnosis. It typically falls within known limitations of cytology with low cellular yield, as seen in our case with negative results despite repeat sampling. In such instances, surgical biopsy is warranted for early diagnosis. Due to the rarity of diagnosis and poor prognosis, there are limited effective treatment options known. In most instances, with diagnosis in advanced stages, palliative care remains the only option. This case highlights the significance of prompt surgical tissue biopsy for early diagnosis with atypical presentations, vague imaging and inadequate cytology findings. A lower threshold for surgical biopsy improves diagnostic yield and may impact outcome if diagnosed at an earlier stage. This abstract is funded by: None