12 beam associated with the object was detected with ALMA. The observed heliocentric velocity, V-r,V- hel=3878 +/- 5.0 km s(-1), immediately establishes the extragalactic nature of the object. The patch velocity is consistent with the velocity of the nucleus of NGC 3269, but not with the radial velocity of the NGC 3269 disk of the galaxy at its position. The similar to 4 '' angular size of the patch corresponds to a linear size of similar to 1 kpc at the galaxy's Hubble distance of 50.7 Mpc. The mass estimated from the (CO)-C-12(2-1) emission is similar to 1.4x10(6)(d/50.7 Mpc)M-2(circle dot), while the attenuation derived from the optical spectrum implies a dust mass of similar to 2.6x10(4)(d/50.7 Mpc)M-2(circle dot). The derived attenuation ratio A ' (B)/(A ' (B)-A ' (R)) of 1.6 +/- 0.11 is substantially lower than the corresponding value for the mean Milky Way extinction curve for point sources (2.3).Conclusions. We established the extragalactic nature of the patch, but its origin remains elusive. One possibility is that the dust patch is left over from the removal of interstellar matter in NGC 3269 through the interaction with its neighbour, NGC 3268.