My Kiya got a lump exactly like you descibed. It was on her back thigh and never went away on it's own. I took her to the vet and they verified it was just a cyst and drained it. They said not to worry if it comes back, because it likely will. It would take surgery to remove permanently, but the vet said it's not worth it unless Kiya was going to be under anesthesia for another reason.
I took Sammy to the vet this weekend for a few issues. The diarrhea was my biggest concern and fortunately it is clearing right up. However, I also asked about a pain in his snout which I thought was tooth pain. He screams in pain every once in a while if you bump his snout even lightly (I do mean scream too, as only you basenji owners can understand). He also stopped playing tug of war with Kiya. Sometimes he would scream in pain when nothing happened to him at all, he would just be sitting there. The vet did a very thourough check of his snout, neck, teeth even did x-rays. Sam never once screamed or made so much as a peep.
The vet found nothing. He thinks Sam probably did have an issue causing him pain at one point and it has since healed up. The vet thinks Sammy learned that when he screams he gets lots of attention from DH and I so now he does it for the attention and at the vet's office he didn't do it since the last thing he wants there is more attention. He was basically diagnosed as being an unruly teenager. The more I think about it, the more I believe the vet too. What makes him scream is so random from time to time, and often it's nothing at all. So good-bye to a large chunk of change to learn our dog is manipulating us for sympathy!
My Sammy likes to play catch with himself as well. He tosses his kong in the air and catches it. Usually he only does this after failing to convince his crabby older sister to join him in playtime, but once he gets started he is completely content to play toss by himself.
I thought I would give everyone an update on Kiya's condition. Her coat has recovered 100%. I think she just went through a summer shedding, and since this was our first summer with her I didn't know what it was. She now has her super soft puppy like fur back and seems to be doing great. Thanks for all of the advice, and now I know what to expect next summer.
I also have a skinny guy. He is up to an almost healthy 23 pounds now, but he is still ribby and you can see his hips pretty easily. He is a bit on the tall side, but I'm really not sure where his ideal weight would be. We've tried many of the same things you have. He is a picky eater, and while very food motivated for training, once you give him the treat he actually ignores it. Our boy is a bit younger though, only 1.5 years. After having him checked thouroughly at the vet, our vet believes he is simply a very active adolescent and as he ages he will start to carry the weight better. The vet says he's in excellent health, and while he's a bit underweight, it's not enough to be concerned about as it might be normal for him. He has the metabolism I wish I had! Good luck with Squiggy!
I think my Bs would do ok in Africa. I live in Phoenix which is about has hot as you can find in the US and they love the summer. They like to layout in the sun when its 105 outside. I make them come in and cool down. In the winter they start shivering if we're out on a walk and its in the 50s. I think they also enjoy our drought conditions, since they have to deal with rain so infrequently. I've actually thought about how the Bs will be the only ones to miss the Arizona heat when or if we ever move.
Kiya will run the B-500 some, but my Sammy is the true B-500 champion. We love it, since we know its burning away his destructive energy! It's really quite amazing to watch him use all the furniture. He truly vaults off the couches and its amazing how huge his jumps are and how long he stays airborne. My friends who have witnessed it are amazed.