Synchronous cancers including parathyroid carcinoma with urinary calculus as the initial sign.

Hyperparathyroidism with urinary calculus as the initial symptom is common; however, carcinomas of the parathyroid gland are rare. Moreover, synchronous cancers have rarely been reported. A man in his 50s presented to our hospital with a 1-month history of left lumbar back pain. After close examination, urinary calculus, parathyroid carcinoma, and lung cancer were detected. He underwent surgical treatment followed by additional anticancer drugs. Two and a half years following his first visit to our hospital, no recurrence has been observed. Parathyroid carcinoma should be considered as a cause of urinary calculus, and synchronous cancers, including rare cancer, can also exist.