BACKGROUND Acalculous cholecystitis is a rare form of gallbladder inflammation that occurs without the presence of gallstones. It primarily affects critically ill patients and warrants prompt treatment given its association with high mortality. Pericarditis, an inflammation of the pericardium, typically arises from viral infections but can also be secondary to rheumatological, malignant, or bacterial causes. The concurrent presentation of both these conditions is rare and should prompt clinicians to investigate for a potential underlying cause. Previous case reports have shown that systemic lupus erythematosus, malignancies, and parasitic or bacterial infections are possible underlying causes of this dual presentation. CASE REPORT We describe a unique case in which acute viral pericarditis initially presented with clinical and imaging findings consistent with acute acalculous cholecystitis. A man in his 40s presented with epigastric pain and community ultrasound findings consistent with acalculous cholecystitis. As part of the workup, a CT scan showed an incidental finding of a pericardial effusion, and transthoracic echocardiogram revealed no evidence of cardiac tamponade. Despite treatment, the patient continued to spike fevers. Consequently, an extensive workup was performed, including pericardial and pleural biopsies, which were negative for rheumatological, bacterial, and malignant causes. After ongoing treatment with non-steroidal anti-inflammatory medications, the patient made a full recovery. CONCLUSIONS This case highlights the importance of recognizing acalculous cholecystitis as an atypical manifestation of acute viral pericarditis. When these 2 conditions occur together, identifying a possible underlying cause is paramount, as the management differs greatly. This case report is one of the few describing the presence of both conditions not due to a primary bacterial, malignant, or rheumatological cause. Viral illnesses can cause inflammatory responses leading to both conditions.