Abstract
RATIONALE: Sarcomatoid hepatocellular carcinoma (SHC) is a rare subtype of hepatocellular carcinoma. Its imaging findings often resemble those of liver abscess, making preoperative diagnosis particularly challenging. To date, there have been no documented cases of SHC with subdiaphragmatic metastases. In this report, we present a case of SHC with subdiaphragmatic metastasis that was initially misdiagnosed as hepatic abscess. In addition, we conducted a retrospective analysis of the clinical and imaging findings to improve the clinical understanding of this disease. PATIENT CONCERNS: A 74-year-old woman was admitted to our hospital with recurrent right upper abdominal pain and discomfort, chills, and fever for >1 month. DIAGNOSES: The patient underwent abdominal computed tomography and magnetic resonance imaging, which revealed multiple nodules and masses in the left lobe of the liver. Furthermore, a thick-walled irregular cystic solid mass was identified in the anterior and subdiaphragmatic regions. Based on these findings, the patient was diagnosed with an abscess. The postoperative pathology confirmed SHC in both the left lobe of the liver and subdiaphragmatic mass. INTERVENTIONS: The patient underwent a left external liver lobectomy. OUTCOMES: The patient's condition deteriorated after surgery, and hepatic encephalopathy developed 1.5 months postoperation, ultimately leading to death. LESSONS: To the best of our knowledge, cases of SHC with subdiaphragmatic metastases are rare, and the preoperative diagnosis presents a significant challenge in clinical practice. More comprehensive case analyses of SHC are needed to enhance the accuracy of clinical and imaging diagnoses.