Management challenges with brown tumor of primary hyperparathyroidism masked by severe vitamin D deficiency: a case report

BACKGROUND Hyperparathyroidism is a disease characterized by excessive secretion of parathyroid hormone, the hormone responsible for calcium and phosphate homeostasis in the body. It can be of three types: primary, secondary, or tertiary. It is essential to bear in mind that in any one patient more than one type of hyperparathyroidism may be found, which may create perplexity regarding the etiology of the case. Hyperparathyroidism can become apparent early in its course when a patient presents with symptoms of abdominal pain, recurrent renal calculi, repeated fractures, or behavior changes. It is generally accepted that bone involvement is a late manifestation of primary hyperparathyroidism. It is imperative to consider that some patients, such as our patient described in this report, may be previously asymptomatic clinically and on the basis of laboratory findings and present with only late skeletal manifestations. Brown tumors are one of the mimickers of lytic lesions of the jaw and need to be ruled out early in the course of management. Researchers in several studies published in high-impact journals have recommended the use of high-dose vitamin D as safe in patients with primary hyperparathyroidism without the risk of raising calcium levels significantly. In our patient, we observed considerable hypercalcemia after high-dose vitamin D therapy, and we propose exercising discretion with the use of high-dose therapies. CASE PRESENTATION We report a case of a 21-year-old Arab woman with a brown tumor who presented with hypocalcaemia. She presented with a mixed picture of primary hyperparathyroidism and severe vitamin D deficiency. CONCLUSIONS Brown tumors, although thought to be a forgotten entity with the advent of early screening for hypercalcemia, is still prevalent, as a handful of patients may present late in the disease course with no early markers, such as in our patient. We emphasize using a holistic approach for early diagnosis and adopting a restricted attitude to treating these benign entities, especially in the context of cosmesis for sensitive locations such as the face. In addition, we express caution in using daily supplementation with a high vitamin D dose to improve vitamin D status and decrease parathyroid hormone.