A 67-year-old woman presented with a persistent cough, sputum production, and left-sided rib pain, which worsened with weightlifting and compression and had persisted for over a month. After one week of symptomatic anti-inflammatory therapy, her symptoms showed no significant improvement. The patient had no notable medical antecedents, no history of smoking or alcohol consumption, no family history of hereditary conditions or calcium-related metabolic disorders, and no history of kidney stones or fractures. On admission, her vital signs were as follows: blood pressure, 105/65 mmHg; height, 158 cm; and weight, 47 kg.

In March 2025, the patient underwent contrast-enhanced chest computed tomography (CT), which revealed multiple areas of bone destruction in the right scapula, sternum, and bilateral ribs, along with local soft tissue density shadows. The patient was referred to the Department of Medical Oncology for diagnostic confirmation, and a whole-body positron emission tomography CT (PET-CT) was performed. PET-CT results showed unevenly reduced bone mineral density, with recurrent osteolytic destruction involving multiple bilateral ribs, the right scapula, sternum, and L1 vertebral body. Notably, the axillary segment of the left sixth rib was identified as the focal point of destruction, with local soft tissue formation measuring approximately 46 × 36 mm. Increased uptake was observed in the local convexity of the left lung, with a maximum SUV of 9·5, and the density of the bilateral humeral bone marrow cavities was unevenly reduced (Figure 1). Cranial magnetic resonance imaging (MRI) revealed a right occipital lobe enhancing nodule with slightly higher T2-weighted imaging (T2WI) signal and a lower T1-weighted imaging signal, measuring approximately 1·1×0·8 cm, with poorly defined margins relative to adjacent meninges. Several T2WI hyperintense nodules were also observed in the occipital cistern, with the largest measuring approximately 0·9×0·6 cm (Figure 2). Based on these findings, metastases were initially suspected. The patient was admitted to the Department of Thoracic Surgery and underwent ultrasound-guided needle biopsy of a mass in the left chest wall. Ultrasound detected a cystic-solid mixed echogenic mass measuring approximately 7·8 x 3·0 cm, predominantly solid, with clear boundaries and irregular morphology. Pathology from the biopsy suggested giant cell-rich lesions consistent with brown tumors secondary to hyperparathyroidism, which are benign bone lesions caused by excessive osteoclastic bone resorption induced by sustained parathyroid hormone elevation. These findings prompted a multidisciplinary team discussion. Immunophenotype of tumor cells: CKpan (AE1/AE3) (-), H3.3G34R (-), H3.3G34V (-), H3.3G34W (-), P63 (partial +), SATB2 (partial +), Ki-67 (approximately 5%). Given the diagnostic uncertainty, the case was discussed at an MDT meeting. During multidisciplinary assessment, the imaging department noted that the patient’s brain MRI showed a right occipital lobe enhancing nodule; based on location and morphology, a meningioma was considered more likely. Concurrently, the Pathology team identified no histopathological evidence of malignancy, recommending differentiation between metabolic diseases and secondary lesions. The sonography team reported a nodule of unknown origin in the left lung lobe and advised repeating neck ultrasonography and performing parathyroid nuclide scintigraphy to assess its nature. Neck ultrasonography revealed a hypoechoic nodule in the upper pole of the left thyroid lobe, measuring approximately 19 mm ×8 mm ×16 mm, with well-defined borders, and irregular shape (Figure 3). Laboratory testing showed a PTH level of 1911·97 pg/mL, which was 21 times higher than the upper limit of normal. The serum calcium level was 3·07 mmol/L, the serum phosphorus level was 0·55 mmol/L, and the alkaline phosphatase level was 547 U/L, respectively. These results suggested significant parathyroid dysfunction. Therefore, we used nuclear medicine to further clarify the diagnosis of these patients. The results of single-photon emission CT/CT (SPECT-CT) parathyroid scintigraphy demonstrated an upper low-density nodule in the left thyroid lobe that was not clearly demarcated from the thyroid parenchyma. Uptake of 99mTc-methoxyisobutylisonitrile (99mTc-MIBI) was increased, suggesting hyperfunctioning parathyroid tissue (Figure 4).

After multidisciplinary consultation, parathyroid carcinoma was initially considered given the markedly elevated PTH level and extensive skeletal involvement. However, the final diagnosis of multiple osteolytic bone lesions secondary to a parathyroid adenoma was established based on the absence of invasive histological features, a low Ki-67 index, and confirmatory immunohistochemical findings. Doctors in the Department of Head and Neck Surgery stated that surgical removal of the parathyroid tumors could significantly alleviate the patient’s symptoms and potentially achieve a curative outcome. The thoracic surgeon advised that thoracic surgery was not required at this stage, as bone destruction secondary to lung cancer was not suspected. Post-parathyroidectomy, the patient’s chest pain improved markedly. It was noted that if the rib bone destruction did not improve after surgery, thoracic surgery and related interventions should be reconsidered. The consensus decision was to proceed with left-sided parathyroidectomy, followed by re-evaluation to determine any further treatment needs.

The patient underwent left upper parathyroidectomy and partial left thyroid lobectomy, which was performed because preoperative fine-needle aspiration of the adjacent thyroid nodule demonstrated benign follicular features and surgical exposure was required. Central neck dissection was not performed because no invasive features suggestive of parathyroid carcinoma were identified intraoperatively, and definitive postoperative pathology confirmed a benign parathyroid adenoma. Intraoperative frozen section analysis suggested a parathyroid adenoma; however, the definitive diagnosis was established based on permanent paraffin sections and immunohistochemical confirmation. The post-frozen-section paraffin pathological report demonstrated the following findings for the left superior parathyroid mass (the lesion): it presented as an irregular grayish-red tissue measuring 2 cm × 1.5 cm × 1.6 cm in dimensions, with a medium-textured cut surface. Immunohistochemical staining revealed positive expression of Syn, CgA, and PTH, negative expression of TTF-1, and a Ki-67 proliferation index of 1%. Based on these results, the lesion was diagnosed as a parathyroid adenoma. Notably, the intraoperative PTH level was recorded at 159·91 pg/mL, demonstrating a significant decline from preoperative levels. No specific preoperative medical treatment was administered to address the moderate hypercalcemia. Following surgical removal of the parathyroid lesion, serum calcium levels normalized promptly, as confirmed by postoperative laboratory testing. Postoperatively, the patient experienced a sore throat with cough and sputum production, which was aggravated during swallowing, but no symptoms such as numbness or carpopedal spasms were reported. Symptomatic treatments included mechanically assisted expectoration, red light therapy, calcium gluconate supplementation, and bromhexine for sputum reduction. On postoperative day two, follow-up measurements revealed a PTH level of 4·63 pg/mL, serum calcium level of 2·30 mmol/L, and serum phosphorus level of 0·52 mmol/L. By postoperative day four, the patient recovered well and was discharged from the hospital.

Two weeks after surgery, the patient’s rib pain had markedly improved. Laboratory review showed a serum calcium level of 1.98 mmol/L, serum phosphorus level of 0·83 mmol/L, and total 25-hydroxyvitamin D level of 17·52 ng/mL. At the last follow-up, the patient was in good general condition, with near-complete resolution of pain and other symptoms, and continued oral calcium supplementation.

I am a 67-year-old woman who was previously in relatively good health. I developed a persistent cough and severe chest pain that disrupted my daily life and sleep. Initial imaging tests at the hospital revealed extensive osteolytic lesions, and I was initially suspected of having malignant bone metastases possibly from lung cancer, which filled me with severe fear and anxiety. Through multidisciplinary evaluation including detailed laboratory tests and advanced imaging, I was finally diagnosed with primary hyperparathyroidism caused by a parathyroid adenoma, not cancer. This brought me immense relief, even though I was confused about this condition at first. After the doctors explained my condition clearly, I underwent surgery to remove the parathyroid adenoma. The surgery and recovery went smoothly, and my symptoms improved significantly within a few weeks: my chest pain eased, my cough subsided, and I gradually resumed the daily activities I had been unable to do before.