Syncope as the initial presentation of pulmonary embolism in two patients with hepatocellular carcinoma: Two case reports and literature review

RATIONALE: Pulmonary embolism (PE) has diverse clinical manifestations and syncope might be the first or only symptom of PE. Tumor disease usually presents with symptoms associated with the primary site, however, PE may be the first manifestation of occult tumors. PATIENT CONCERNS: Here, we report 2 patients admitted to our hospital because of syncope. One patient had a chronic hepatitis B history of more than 20 years and the other patient had chronic heavy drinking for many years. Neither patient had been diagnosed with neoplastic disease before admission. DIAGNOSES: Clinical examinations, including laboratory tests and imaging tests upon admission demonstrated PE resulting in syncope. Furthermore, malignant hepatocellular carcinoma (HCC), inferior vena cava, and right atrium tumor thrombus were diagnosed. INTERVENTIONS: Thrombolysis and anti-coagulation therapy were performed immediately after the diagnosis of PE. Twenty-seven HCC patients with PE in 27 articles from 1962 to 2020 in the PubMed database were reviewed. OUTCOMES: The improvement was achieved that no syncope recurred after treatment of PE. The oxygen partial pressure increased and the D-dimer level decreased. The clinical characteristics of 27 HCC patients with PE were summarized and analyzed. LESSONS: It is important for clinicians to be aware that occult carcinoma might be a reason for patients with PE presenting with syncope. If PE cannot be explained by common causes, such as our patient, and HCC should be highly suspected when inferior vena cava and right atrial mass are found on imaging tests.