Alveolar Echinococcosis of the Parotid Gland-An Ultra Rare Location Reported from Western Europe

(1) Background: Alveolar echinococcosis (AE) is restricted to the northern hemisphere with high endemic regions in Central Europe, North and Central Asia as well as Western China. The larval stage of Echinococcus multilocularis (E. multilocularis) causes AE with tumor-like growth. Humans are accidental hosts. This report is on the first case of AE becoming clinically manifested in the parotic gland. (2) Case presentation: A 52-year-old male patient presented with progressive and painful swelling of the right parotid gland persisting for one year. We performed a partial parotidectomy. The histological examination and immunohistological staining revealed larval stage of E. multilocularis. (3) Conclusion: E. multilocularis is known to infect animals and humans coincidentally, and leads to AE. It is one of the most life-threatening zoonoses in Europe. It typically manifests in the liver (50-77%), with further spreading to other organs being a rare phenomenon. Echinococcosis should be considered in the differential diagnosis of lesions of the parotid gland in endemic areas, but AE has not been described so far in the parotid gland as the sole manifestation and, therefore, impedes the correct diagnosis. A complete resection should be the aim, however, preservation of the facial nerve and adjuvant albendazole therapy is mandatory.