Adler cites Lexicon Ambrosianum 287.
Otherwise this toponym is poorly attested, but it does occur (in the accusative case) in Georgius Cedrenus 2.213, part of his narrative of the efforts of Basil I (Byzantine emperor 867-886) to overcome the Paulicians. He glosses it there as 'the metropolis of the Manicheans'.
Should this not be the correct referent of the present entry, other tenuous possibilities are:
[NF] Cameria, an unlocated site in central Italy. See BCA Map 44, Unlocated Toponyms.
[DW] Kameiros, on Rhodes; cf. alpha 1982, kappa 280.