  We report on an analysis of \fermi data from four year of observations of the
nearby radio galaxy Centaurus A (Cen A). The increased photon statistics
results in a detection of high-energy ($>\:100$ MeV) $\gamma$-rays up to 50 GeV
from the core of Cen A, with a detection significance of about 44$\sigma$. The
average gamma-ray spectrum of the core reveals evidence for a possible
deviation from a simple power-law. A likelihood analysis with a broken
power-law model shows that the photon index becomes harder above $E_b \simeq 4$
GeV, changing from $\Gamma_1=2.74\pm0.03$ below to $\Gamma_2=2.09\pm0.20$
above. This hardening could be caused by the contribution of an additional
high-energy component beyond the common synchrotron-self Compton jet emission.
A variability analysis of the light curve with 15-, 30-, and 60-day bins does
not provide evidence for variability for any of the components. Indications for
a possible variability of the observed flux are found on 45-day time scale, but
the statistics do not allow us to make a definite conclusion in this regards.
We compare our results with the spectrum reported by H.E.S.S. in the TeV energy
range and discuss possible origins for the hardening observed.
