What diseases can develop from a tumor in the parathyroid gland?

Several: High calcium from a parathyroid tumor can cause stones, bones, moans, and groans. Stones = kidney stones. Bones = increased fracture risk, and generalized aches. Moans = mental depression or confusion. Groans = GI complaints of constipation, nausea, and ulcers. Fortunately, things rarely progress this far, since calcium testing is included in a routine chemistry panel.

Many symptoms: The list is long: bone pain, osteopenia, osteoporosis, bone fractures, osteogenesis fibrosis cystica, kidney stones, kidney failure, pancreatitis, abdominal pain, ulcers, depression, fatigue, forgetfulness, insomnia mong others. The cure is surgery, surgery, surgery!