Objective  To summarize the clinical manifestations and pathological features of alveolar echinococcosis (AE) in Tibet, China.

  Methods  Complete pathological data of all patients with surgical resection of AE in the Tibet Autonomous Region People's Hospital from September 2013 to April 2021 were retrospectively studied. Clinical and imaging findings, pathological results, treatment methods, and prognosis information were extracted through the electronic case system. The pathological sections were re-read by microscope to observe the pathological changes.

  Results  A total of 44 AE patients were included. There were 17 males and 27 females; the average age was (36.2±12.3) years; 32 cases were farmers or herdsmen. The most common clinical manifestations were gastrointestinal symptoms (54.5%), followed by respiratory symptoms (13.6%), and 29.5% of patients had no obvious clinical symptoms. CT examination showed that 23 cases had a single lesion and 21 cases had multiple lesions (15 cases with multiple intrahepatic lesions and 6 cases with multiple organ involvement); 33 cases were diagnosed as AE by CT. The specimens for histopathological examination were mainly masses, with a diameter of 1.0-23.0 cm, and the sections were honeycombed. Microscopically, there were small vesicles of different sizes and shapes in the lesions, and the outer wall of the vesicles was a thin layer of pink stratum corneum. The proliferation of vesicles was mainly exogenous. In the early stage, a large number of eosinophils infiltrated around necrotic vesicles with the formation of granuloma; dust-like calcification and massive necrosis were seen in late old lesions. Early granulomatous lesions and late old lesions were mixed in all 44 cases, of which 5 cases were accompanied by abscess formation. A total of 31 cases underwent radical surgery, and 13 cases underwent palliative surgery and drug treatment. After a follow-up of 2-82 months, 3 cases died and 41 cases survived.

  Conclusions  AE patients in China's Tibet are mainly young farmers and herdsmen, mostly women. The liver is the main organ involved, and a few cases can involve the lung or multiple organs. The clinical manifestations are related to the affected organs, and symptoms of the digestive system are more common. Imaging examination has a good reference value for the auxiliary diagnosis of typical cases, but atypical cases or cases complicated with abscess must be confirmed by pathology. Pathological examination shows that the body of alveolar echinococcus with a spherical vesicular structure, and the lesions of different periods often exist together. Most patients have a good prognosis by radical surgical treatment.