A lamellar phase confined between parallel walls changes its structure when compared with the bulk system, The system is studied here in the Monte Carlo simulations of the Landau-Ginzburg model of a ternary mixture of oil, water, and surfactant. In the case of strongly hydrophilic boundary conditions at the walls, we observe strong topological fluctuations in the form of passages. As we change the distance between the walls we observe the formation of two surfactant layers, then the microemulsion between two layers, and finally four surfactant layers. The transition is marked by the peaks in the average Euler characteristic and in its variance. In the case of strongly hydrophilic boundary conditions at one wall and strongly hydrophobic boundary condition at the other, we observe under dilation a permanent deformation of layers in the middle of the system. In the case of weakly hydrophilic boundary conditions, the system exhibits strong topological fluctuations (passages and droplets) and the lamellar phase which forms is perpendicular to the bounding walls. In this case, edge dislocations form close to the walls. We also simulate an onion vesicle in a cubic pore and edge dislocations in slits, and show that the passages appear near a dislocation core.