S5449 An Unusual Presentation a Metastatic Hepatic Tumor With Rapid Resolutions Following Treatment Pembrolizumab

Introduction: Malignant hepatic lesions are classified into primary malignancies or hepatic metastasis (most frequent). Necrotic liver masses may be associated with a solitary necrotic nodule, which is usually benign, or large and rapidly progressive hepatic tumors or metastasis. Here we present a case of a squamous cell carcinoma (SCC) of the lung that was diagnosed based on the acute development of a substantially large necrotic liver mass on imaging. Case Description/Methods: A 71-year-old woman with a past medical history of a pulmonary nodule, stage IIIb chronic kidney disease, presented to the outpatient clinic for follow-up of abnormal imaging findings. History of a 1.3 cm right upper lobe (RUL) lung nodule on screening computed tomography (CT) chest without contrast 6 months. A few months later, the patient developed new onset hemoptysis and repeat CT chest without contrast demonstrated an increased size of the RUL nodule (3.1 cm), increased size of a right adrenal mass, and the new development of a centrally necrotic mass in the right hepatic lobe, measuring 6.5 × 10 × 9.3 cm. Due to concerning CT findings, the patient underwent positron emission tomography scan which demonstrated a cavitary hypermetabolic RUL lung mass (3.5 × 3.3 cm) and a large intralobar necrotic mass spanning both the right and left hepatic lobes (10.0 × 7.1 cm). The patient was sent for hepatic mass biopsy, which resulted in a positive diagnosis for squamous cell carcinoma, suspected lung primary. The patient was evaluated by oncology and started pembrolizumab along with palliative radiation therapy, with a significant decrease in the size of lung and liver masses after 6 months of treatment. Discussion: The etiology of large necrotic hepatic masses is not well discussed in the current literature. Our case shows a significantly large necrotic liver mass that was found to be a metastasis from primary lung SCC. This is an unusual presentation of hepatic metastasis given the rapid development and substantial size of the hepatic mass, which typically range from 1-3 cm in diameter. Additionally, the patient’s response to 6 months of pembrolizumab demonstrated an impressive reduction in the hepatic metastasis and warrants further investigation into the use of the drug for the treatment of late-stage squamous cell carcinoma of the lung.