The authors agree that this surname derives from the Italianization of the Arabic term ḥaggām (also transcribed h'ağğām), which designated the practitioner of minor surgery: applier of leeches, barber, surgeon or healer. The Latinized form Cangemius appears as a possible alternative etymon, indicating in that case a dialectal alteration of a surname of Latin origin (see also Cancemi).

E. Rossoni places the main diffusion in eastern Sicily, especially in the Messina and Catania areas, and in the Reggio Calabria area, with presence in localities such as Rosarno, Palmi, Gioia Tauro and Villa San Giovanni. He also mentions the variant Gangeni, practically disappeared, which seems native to Calabria, with a focus in the Reggio Calabria area.

F. Miranda broadens the geographical panorama: besides eastern Sicily and Calabria, he notes presence in almost all the Italian regions, among them Lombardy, Lazio, Piedmont, Tuscany, Liguria, Campania and Emilia-Romagna. In Sicily he also documents it in the provinces of Syracuse, Palermo, Enna, Ragusa and Trapani. Another source agrees with the Arabic etymology and adds that it is a southern surname.