Sarcoidosis and primary hyperparathyroidism simultaneously occurring in a hypercalcemic patient

Sir,

A 60-year-old African-American female with a history of sarcoidosis and hypertension, presents to the clinic with complaints of nausea, vomiting, dehydration and constipation. Her physical examination was unremarkable. During the routine laboratory analysis it showed hypercalcemia of 10.8 mg/dl (N = 8.2-10.2mg/dl). Serum phosphorus levels were 3.9 mg/dl (N = 3.5-4.5 mg/dl). Intact PTH level was 120 pg/ml (N = 10-75 pg/ml) and 25-Hydroxy vitamin D₃ was 36 ng/ml (N = 20- 110 ng/ ml). Her bone-specific alkaline phosphatase was 23 U/L (N = 14.2-42.7 U/L). Patient serum creatinine was 0.8 mg/ dl. Other laboratory values including thyroid and liver function tests and a bone scan was normal. Her chest X-ray showed bilateral lymphadenopathy consistent with her diagnosis of sarcoidosis. Her serum ACE was checked and it was elevated at 72 U/L (N = 8-52).

She was adequately hydrated and bisphosphonates was tried but her calcium levels remained persistently elevated. A trial of steroids, prednisone 1 mg/kg for 5 days was tried but it failed to relieve her symptoms and she continued to have hypercalcemia. Finally in the presence of elevated PTH, a sestamibi imaging of the parathyroid [Figure 1] was done that showed, right inferior parathyroid gland adenoma. Surgery was consulted and the patient underwent surgery with removal of right inferior parathyroid gland that weighed 470 mg. Histology showed noncaseating granulomas, consistent with sarcoidosis [Figures 2 and 3] surrounded by multiple colloid-filled thyroid follicles of varying sizes lined by benign epithelium. The parathyroid tissue also contained non caseating granuloma. Following surgery patient did well and her symptoms resolved with normalization of her calcium levels at 9.2 mg/dl and PTH levels. The patient has been followed periodically for the past 10 years with no recurrence of the disease.

Figure 1: Tc99m Sestamibi scan, showing uptake in the right inferior parathyroid gland

Figure 2: Normal thyroid follicle

Figure 3: Noncaseating granuloma within the thyroid follicle

Sarcoidosis and primary hyperparathyroidism have rarely been reported to coexist [Table 1]. In sarcoidosis the elevated calcium levels is expected to cause suppression of the PTH levels. However, occasionally these two separate entities can coexist causing persistent hypercalcemia[¹²] which is both of a diagnostic and therapeutic challenge.[³] Response is variable with surgery alone or both with steroid therapy and surgery. In our case, parathyroidectomy cured the condition and the patient has been followed for an extended period of time with no recurrence of her symptoms or the disease.

Table 1: Cases with coexisting sarcoidosis and primary hyperparathyroidism, with the treatment plan

We believe that primary hyperparathyroidism that contributed to her hypercalcemia with little to no contribution by her sarcoidosis. Finally to our knowledge this is the second case reported of the finding of sarcoid granuloma both in parathyroid and thyroid gland with coexistence of primary hyperparathyroidism.[⁵]