A 46-year-old female patient had a history of elevated alkaline phosphatase (AKP) for 4 years. She had occasional thirst, with no abdominal pain, abdominal distension, acid reflux, heartburn, constipation, dyspepsia, or nocturia. The history of renal insufficiency was denied. The patient had regular physical examination every year and found that his AKP level increased progressively. Osteoporosis was found by physical examination two years ago with no bone pain or fracture history. The patient's menstruation is still regular, and there is no obvious history of dysmenorrhea.
Blood test results one month before operation showed that AKP was 294 U/L (normal range 30-100 U/L), PTH 981.20 pg/mL (normal range 15-65 pg/mL), calcium 2.93 mmol/L (normal range 2.00-2.60 mmol/L), phosphorus 0.64 mmol/L, Vitamin D 6.97 ng/mL (normal range >=30 ng/mL). Right forearm bone mineral density detection showed BMD 0.391, Z score -5.33, and t score -5.44. Computed tomography scan showed posterior superior mediastinal was occupied with a cystic solid tumor whose maximum cross-section size was about 3.3 x 1.9 cm (Figure 1A-1D). No special signs were found by neck ultrasound. The patient underwent 99mTechnetium sestamibi scanning, indicating a mass with increased uptake of imaging agent in the posterior mediastinum (Figure 1E-1F).
The patient had daily subcutaneous injection of a total amount of 100-300 IU per day of salmon calcitonin preoperatively due to hypercalcemia and underwent single-port thoracoscopic resection of the mediastinal tumor. The tumor was carefully removed by ultrasonic scalpel. The volume of the tumor was about 6.0 x 4.2 x 1.0 cm at pathological examination. Postoperative pathology confirmed parathyroid adenoma (Figure 2).
The PTH and blood calcium levels decreased instantly after the operation. The PTH level on the first day after the operation was 93.96 pg/mL, and on the second day after the operation was 7.29 pg/mL. However, on the fourth day after the operation, the PTH level raised to 65.61 pg/mL (normal range 15-65 pg/mL) and continued to rise to 159.2 pg/mL one month after the operation. Serum calcium concentration was still within the normal level and no specific symptoms were shown. Meanwhile, the vitamin D level was found lower than the normal level in the first month after surgery. So the patient was supplemented with vitamin D 800 IU per day. The PTH level continues to decrease, whereas vitamin D levels continue to rise ever since exogenous vitamin D was supplemented. One year after the operation, serum PTH, calcium, and vitamin D levels returned to normal (Figure 3).
The timeline of clinical interventions for this patient was shown in Figure 4.