[Pediatric Alveolar Echinococcosis with Pulmonary and Hepatic Involvement and Literature Review: A Rare Case]

Alveolar echinococcosis (AE) caused by Echinococcus multilocularis, is a rare but potentially fatal zoonotic infection. AE most commonly presents with multiple cysts in the liver, may spread to other organs through infiltration or metastasis and can mimic malignancy with fatal consequences if not diagnosed early. Its occurrence in childhood is extremely rare and simultaneous hepatic and pulmonary involvement has been reported only in a few cases. This report aimed to discuss a pediatric AE case with concurrent hepatic and pulmonary involvement, initially misdiagnosed as malignancy, in the light of current literature. The presenting complaints, physical examination findings, diagnostic methods, treatment and follow-up results of a pediatric AE case with hepatic and pulmonary involvement were documented and pediatric AE cases available in the literature were reviewed. A 10-year-old boy presented with a fivemonth history of intermittent fever and weight loss. At admission, multiple cystic lesions were detected in the liver parenchyma, along with widespread cystic foci in both lungs. Laboratory tests revealed marked eosinophilia (44.5%), and E.multilocularis serology (IgG, IHA) together with Western blot (Em70, Em90 positivity) confirmed the diagnosis. According to the "parasitic mass in the liver, neighboring organs involvement and metastasis" classification; the case was staged as P4N0M1. Since surgical resection was not feasible, continuous albendazole therapy (15 mg/kg/day) was initiated. After one year of follow-up, significant radiological regression was observed, without new lesion development or treatment-related toxicity. Pediatric AE with multi-organ involvement may mimic malignancy and cause diagnostic delays. Early diagnosis and appropriate antiparasitic therapy can achieve favorable outcomes even when surgery is not feasible. However, the prolonged duration of therapy and the lack of a well-defined treatment endpoint pose significant challenges in terms of monitoring and potential toxicity. More clinical data are needed to establish optimal treatment duration and follow-up protocols in children.