hypercalcemia with low associated PTH- need opinion of another endo.

[caravan25]

I am 31, male. 4 months ago, I had blood tests as part of a physical.I was found to have high serum calcium (11.4). All other results normal.TSH level in normal range; 2.656. Parathyroid obtained w/ low-normal results (13 pg/ml in range of 12-65). There is a history of hypercalcemia in my family, never treated, and though maybe due to hyperpara., parathyroid levels unknown. Primary Dr. tested my blood twice after: decreasing Ca. (11.1 and 10.7, in range of 8.5-10.6). Also had CT of chest/abdomen with normal results due to some blood in sputum (later determined as coming from a sinus infection). Under treatment of an Endo., I had more tests: Cal. now normal, 24 urine Cal. normal, vitamin D deficient, low-normal phosphate. I am VERY afraid that hypercal. is being caused by malignancy, but the Endo. is not worried, insists that she sees nothing in my workup to suggest malignancy, and that the possibility of this would be a last-case scenario. She insists that with my age, mild Ca. Elevations, and ambulatory state, I would be the “first one” she’s heard of to have Humoral Hypercalcemia of Malignancy while not sick in the hospital. Meanwhile, she has me on vitamin D supplements (insists it will not raise my Ca. because of the low amt. prescribed) and I will take more blood tests and bone density scan. She believes it to be a “tubular” syndrome. I am confused about all of this, as what I have read on sites such as e-medicin suggest that I probably have cancer. Does vitamin D deficeny futher suggest cancer? Are more tests/scans called for? She felt PTHrP test unnecessary...Thanks.

[Mark Lupo, M.D.]

The high calcium and vit D deficiency is not a usual combination -- not sure why it was 11.1 and now nl.  I think Vit D treatment is fine as long as Ca++ is monitored closely.  The low PTH suggests that the high Ca++ initially discovered was "non-parathyroid" origin but if it were a malignancy the Ca++ would typically be on the further rise.  Make sure both 25-OH-D and 1,25-OH2-D were both checked to assess vit D.  If Ca increases again and PTH is still low then check PTHrp as well as protein electrophoresis of blood and urine to exclude the unlikely multiple myeloma (if not already done).