buckeye rot of tomato
Buckeye rot-I have only observed this disease in processing fields. The characteristic symptom is the dark, concentric pattern of necrosis on tomato fruit.
Figure 1. A processing tomato with Buckeye rot. 
Figure 2. Four processing tomatoes with diverse symptoms of Buckeye rot. 
Figure 3. Four tomatoes with Buckeye rot with a range of symptoms. Concentric circles of necrosis is typical of Buckeye rot.