Flames appeared to be centered over the massage business in the 800 block of North Euclid Street, but were also affecting nearby storefronts, including an insurance office, travel agency and shipping business.
Firefighters said it appears to have started from a business that may have had electrical code violations.
About 75 firefighters battled the fire that started around 10 p.m.
The flames were shooting out of the roof of the shopping plaza and the roof appeared to be destroyed.
There were no immediate reports of injuries.