Background:  The rare localizations of hydatidosis represent an interesting topic, especially with reference to epidemiological and diagnostic problems. Hydatid disease, common in Mediterranean countries, still remains endemic in some regions of Italy.

Methods:  In the period April 1983−October 2003 73 patients with hydatid disease were observed.

Results:  Seven patients (9.5%) presented a primary rare localization (thyroid, kidney, sacrospinal muscle, peritoneum and spleen). The main peculiarity of primary rare hydatidosis localizations concerns diffusion of the infecting embryo; the most reliable hypothesis is that liver and lung can be bypassed through precapillary anastomosis between pre‐ and post‐parenchymal circulation. The new imaging techniques allow a correct topographic evaluation and so a radical surgical treatment. The chemotherapy, complementary to surgery, produced degenerative modifications of parasite in 75.8% of the present cases and reduction of recurrence from 23.3% to 6.7%. At follow up of 1−5 years no patients had recurrence.

Conclusion:  It is important to be aware, especially in countries where echinococcosis is endemic, that it is possible to find an echinococcosis cyst in a rare localization.