A lamp with an LED array is disclosed. The centralized nature of the LEDs allows the LEDs to be configured in a filament-like way using a supporting power structure, near the central portion of the optical envelope of the lamp. In example embodiments, the LEDs are cooled by a fluid medium to enable the LEDs to maintain appropriate mechanical stability and operating temperature. In some embodiments, the lamp operates at a power of at least 5 watts. Since the LED array can be centralized to form a filament-like structure, the light pattern from the lamp is not adversely affected by the presence of a heat sink or mechanical supporting parts. In some embodiments, phosphor is used provide wavelength conversion. The phosphor can be suspended within the optically transmissive fluid medium, placed remotely in the lamp structure, or applied to un-encapsulated LED die.