2497 Hydatid Cyst Masquerading as Appendicitis

Abstract

INTRODUCTION: Human echinococcosis (HE) is a zoonosis and can cause life-threatening tissue cysts in the liver. We present a case of an unusual presentation of hepatic echinococcosis diagnosed and treated in the United States (US). CASE DESCRIPTION/METHODS: A 23-year-old woman who emigrated from Ecuador to the United States presents to the ED with headaches, fevers and abdominal pain associated with vomiting and rigors. She denied sick contacts and recent travel. She noted 4-5 similar episodes in the past that self-resolved. Her vitals were significant for a fever of 102.3°F and heart rate in 120s. Her labs were significant for a WBC 14.8 k/mm3 but the comprehensive metabolic panel was within normal limits. Exam revealed a supple neck and right lower quadrant tenderness. Due for concerns of appendicitis, she got a CT A/P C+, which was significant for a 4.2 × 2.6 cm and 1.3 cm low-density lesion in the right hepatic lobe. She was started empirically on flagyl and ciprofloxacin and discharged the next day. An outpatient MRI confirmed a cystic neoplasm in segment 5 of the liver with septation. Serum workup included a negative echinococcus antibody and she was referred to a surgical oncologist. She underwent liver segment 4 and 5-6 tumor resections without any complications. Pathology revealed calcified echinococcal cysts with extensive necrosis and abscess formation suggestive of microscopic areas of rupture. She was started on albendazole and is doing well. DISCUSSION: Echinococcosis is a zoonotic disease, with a two-host lifecycle and occurs in humans when Echinococcus eggs infect the liver (70%) and lungs (20%). After ingestion of eggs, the embryos escape and penetrate the intestinal mucosa, enter the portal circulation and then are trapped in the liver. Human cystic echinococcosis (CE) is the most common type of HE. The greatest prevalence of HE is in temperate areas such as parts of South America, North Africa, Asia and Australia. Diagnosis is made on imaging by US, CT and MRI. Treatment includes surgical resection, percutaneous drainage and anti-parasitic agents. Although the vast majority of cases occur outside the US, cases within the US exist and are incidentally found. Despite progress in controlling echinococossis, this condition remains a public health problem in endemic countries and a cause of morbidity and mortality. It should be included on the differential of a patient from an endemic area found to have cystic lesions on liver.