Here’s a case report that appeared as “Lesson of the Week” in the British Medical Journal.

A 53 year old woman of Pakistani origin who had been treated for breast cancer went to her doctors regularly over the next two years with severe widespread muscuIo skeletal pain. When it was misdiagnosed as metastatic bone disease, she was put on the usual drugs for that condition. Her pains worsened, but prior to going on a planned combination chemotherapy treatment, she went for a six-week summer trip to visit her family in Pakistan. On her return to the U.K., her symptoms had completely resolved. Chemotherapy was delayed, and a whole body CT scan showed no evidence of metastasis. Symptoms showed up again after another British winter. Eventually, her severe vitamin D deficiency was recognized and treated appropriately.

You can read more details about this important lesson here.

Source: redorbit