I thought fig also, but it seems to be a lot larger. Then, I noticed a third photo, which I guess I didn't see before (my laptop is having issues downloading pix). It could well be a fig but the seeds don't look like fig seeds. An heirloom tomato is a good guess also. Def not quince.
From the inside, I'd say it was an heirloom tomato. My brother gives me tomatoes off the vine and some have really super odd shapes. The inside definitely looks tomoato. I would have eaten it