This paper studies the fluctuations of the mutual information of a class of multiple-input multiple-output (MIMO) channels with arbitrary correlated noise in the large system limit. We provide a deterministic approximation of the ergodic mutual information, which is asymptotically accurate as the number of antennas grows, and study its fluctuations around this value under the form of a central limit theorem (CLT). This result can be used to predict the outage capacity for slow fading channels. The channel model considered in this contribution has a particular application in the context of distributed antenna or network MIMO systems where the path loss between any pair of transmit and receive antennas has a different value. As shown by simulations, the approximations are very accurate for channels of small dimensions.