Misdiagnosis of brown tumour caused by primary hyperparathyroidism: a case report with literature review

Brown tumor causing pathologic fracture of the ipsilateral femur and pelvis in a pregnant woman: a case report

We present the case of a 30-year-old pregnant woman who was found to have an aggressive-appearing osteolytic lesion of the left distal femur in the setting of hypercalcemia. Biopsy confirmed a brown tumor secondary to hyperparathyroidism. She underwent a successful parathyroidectomy followed by a Cesarean section. Postpartum, she sustained pathologic fractures of the ipsilateral femur and pelvis due to a fall, requiring operative fixation. She progressed to uncomplicated healing following surgical management. Although brown tumors can appear aggressive on imaging, they typically resolve following treatment of the underlying hyperparathyroidism. Pathologic fractures should be managed according to standard orthopedic principles. Clinicians should include brown tumors in the differential diagnosis when evaluating osteolytic lesions, particularly in the presence of hypercalcemia.

Diagnostic challenge of the brown tumors in developing country: A case series

INTRODUCTION AND IMPORTANCE

Brown tumors are non-neoplastic reactive tissue with osteoclasts multinucleated giant cells, and vascular and proliferative fibrous tissue. Hemorrhage results in significant bone resorption caused by hyperparathyroidism. This study provides information about the diagnosis challenge for brown tumor cases.

CASE DESCRIPTION

We report four cases that experience pathological fractures with moderate pain, multiple lytic lesions, severe hypercalcemia, increased ALP (Alkaline Phosphatase), and PTH (Parathyroid Hormone). Abnormal parathyroid mass was found in ultrasound. A bone scan described increasing radio uptake in various bones, a whole body scan, or parathyroid scintigraphy with 99mTc-MIBI. Eventually, in all cases, the diagnosis of the brown tumor was confirmed through histopathological examination, which showed multiple nucleated giant cells with a deposit of hemosiderin pathognomonic for the brown tumor, and the diagnosis of primary hyperparathyroidism (PHPT) was confirmed in all cases.

CLINICAL DISCUSSION

These cases show that initial misdiagnosis of brown tumors as other bone tumors. A definitive diagnosis of brown tumors requires more than just histological confirmation. A comprehensive evaluation encompassing laboratory tests, imaging studies, clinical symptoms, and a multidisciplinary orthopedic-oncology board discussion is essential. Observations show that treating hyperparathyroidism alleviates the osteolytic lesions caused by brown tumors, despite the lack of clinical guidelines.

CONCLUSION

Based on a review of the literature and our clinical experience, we recommend screening serum calcium, phosphorus, and PTH levels in patients presenting with multiple lesions and widespread bone pain. This screening aims to rule out multiple bone lesions caused by PHPT.

Brown Tumors: The Hidden Face of Primary and Renal Hyperparathyroidism Amid Real-Life Settings

Brown tumors, an exceptional bone complication of severe primary (PHP) or renal (secondary) hyperparathyroidism (RHP), are caused by long-standing, elevated parathormone (PTH)-induced osteoclast activation causing multinucleated giant cell conglomerates with hemosiderin deposits in addition to the local production of cytokines and growth factors. We aim to present an adult case series including two females displaying this complication as part of a multidisciplinary complex panel in high PTH-related ailments. The approach was different since they had distinct medical backgrounds and posed a wide area of challenges amid real-life settings, namely, a 38-year-old lady with PHP and long-term uncontrolled hypercalcemia (with a history of pregnancy-associated PHP, the removal of a cystic jaw tumor, as well as a family and personal positive diagnosis of polycystic kidney disease, probably a PHP-jaw tumor syndrome), as well as, a 26-year-old woman with congenital single kidney and chronic renal disease-associated RHP who was poorly controlled under dialysis and developed severe anemia and episodes of metabolic acidosis (including one presentation that required emergency hemodialysis and was complicated with convulsive seizures, followed by resuscitated respiratory arrest). Both subjects displayed a severe picture of PHP/RHP with PTH levels of >1000 pg/mL and >2000 pg/mL and elevated serum bone turnover markers. Additionally, they had multiple brown tumors at the level of the ribs and pelvis (asymptomatically) and the spine, skull, and pelvis (complicated with a spontaneous cervical fracture). As an endocrine approach, the control of the underlying parathyroid disease was provided via surgery in PHP (for the postparathyroidectomy hungry bone syndrome) via medical intervention (with vitamin D analogs) in RHP. Additionally, in this case, since the diagnosis was not clear, a multidisciplinary decision to perform a biopsy was taken (which proved inconclusive), and the resection of the skull tumor to confirm the histological traits. This series highlights the importance of addressing the entire multidisciplinary panel of co-morbidities for a better outcome in patients with PHP/RHP-related brown tumors. However, in the instance of real-life medicine, poor compliance and reduced adherence to recommendations might impair the overall health status. Thus, sometimes, a direct approach at the level of cystic lesion is taken into consideration; this stands for a narrow frame of decision, and it is a matter of personalized decision. As seen here, brown tumors represent the hidden face of PHP/RHP, primarily the complex and severe forms, and awareness is essential even in the modern era.

Brown Tumor From Secondary Hyperparathyroidism Mimicking Metastatic Renal Cell Carcinoma in a Patient With End-Stage Renal Disease

Brown tumors (also known as osteitis fibrosa cystica) are rare complications of end-stage renal disease (ESRD) and secondary hyperparathyroidism (HPT), characterized by focal bone lesions that resemble neoplasms. They are often misdiagnosed as metastatic bone disease, especially in patients with a history of malignancy. We present a case of a 60-year-old man with a history of renal cell carcinoma (RCC), and ESRD on hemodialysis (HD), who developed diffuse bone lesions on imaging with osteolytic/osteoblastic appearance concerning metastases, but on further workup was found to have brown tumors. We discuss the treatment and outcome and briefly review the relevant medical literature.

Unusual body weight loss due to primary hyperparathyroidism: A case study with literature review

Brown tumors (osteitis fibrosa cystica) are rare pathognomonic signs that occur in patients with primary hyperparathyroidism (PHPT). Brown tumors can exist in multiple bones and can easily be misdiagnosed as a metastatic tumor or multiple myeloma. It is also localized in the forearm, humerus, and leg. The symptoms of hypercalcemia, pathologic fracture, and bodyweight loss may increase the diagnostic difficulty of brown tumors because multiple myeloma and bone metastasis also show the same symptoms. We studied a 68-year-old woman who had experienced unusual bodyweight loss in the past 6 months (56kg-40kg) and bone pain. She went to the hospital after a fall with a complaint of bone pain. An X-ray revealed a left bubbly-like cystic change and multiple fractures at the left ulna midshaft. Upon investigation, the level of intact parathyroid hormone was ascertained to be 1800 (normal: 10-60) pg/ml. Microscopically, the tumor demonstrated a benign bone lesion and was compatible with osteitis fibrosa cystica due to PHPT. The parathyroid scan (Tc-99 m sestamibi) indicated right parathyroid hyperplasia, which was later confirmed by a parathyroidectomy. She was diagnosed with osteitis fibrosa cystica associated with PHPT due to a parathyroid adenoma. PHPT can be presented with multiple fractures, bone pain, and bodyweight loss. Therefore, if a patient presents these symptoms, PHPT should be considered.

Primary Hyperparathyroidism With Brown Tumor of the Mandible Misdiagnosed as a Giant Cell Tumor: A Case Report

In this case study, we present an incidentally discovered giant cell granuloma, which, upon detailed investigation, led to an unexpected diagnosis. A 36-year-old woman exhibited a bone lesion in the right retromolar trigone area, initially suspected of being malignant. However, histopathological examination revealed a giant cell tumor of bone. Further biochemical profiling, including serum calcium, phosphorus, and parathyroid hormone (PTH) levels, showed elevated PTH and hypercalcemia, prompting consideration of primary hyperparathyroidism and the diagnosis of a brown tumor due to this condition. This case underscores the importance of considering brown tumors associated with primary hyperparathyroidism as a potential differential diagnosis in patients with lytic bone lesions.

Multiple Bone Cysts Caused by Hyperparathyroidism: A Case Report and Review of the Literature

Background

Brown tumor, a skeletal complication of severe hyperparathyroidism, comprises reparative granulation tissue and proliferating fibrous tissue with hemosiderin deposition. Multiple brown tumors are extremely rare complications of primary hyperparathyroidism.

Case Report

A 41-year-old woman presented with pain in the left knee. Radiography showed multiple cystic lesions in both femurs and the left proximal tibia, and additional radiography showed multiple cystic lesions in the left humerus and ulna. Magnetic resonance imaging (MRI) revealed multiple cystic lesions in the bilateral femurs, left proximal tibia, and ilium. Laboratory tests revealed hypercalcemia (albumin-corrected calcium level, 13.9 mg/dl), hypophosphatemia (phosphate level, 1.6 mg/dl), elevated level of alkaline phosphatase level (614 U/l), and markedly elevated parathyroid hormone (PTH) level (1,070 pg/ml; normal range=10-65 ng/l). 99mTc-hexakis-2-methoxyisobutyl-isonitrile scintigraphy revealed tracer accumulation in the left upper parathyroid gland, which was consistent with parathyroid tumor. Although resection of the parathyroid tumor was planned, the patient developed parathyroid apoplexy before tumor excision. After the parathyroid apoplexy, serum calcium and PTH levels temporarily normalized. Resurgence of the PTH level was observed 2 years after the diagnosis, and the patient underwent left upper parathyroidectomy. One year after the tumor excision, the patient had no symptoms, and MRI showed shrinkage of the cystic bone lesions.

Conclusion

This report emphasizes the importance of considering hyperparathy-roidism as a differential diagnosis for patients with multiple bone lesions.

Brown Tumour in Chronic Kidney Disease: Revisiting an Old Disease with a New Perspective

Osteitis fibrosa cystica (OFC) and Brown Tumours are two related but distinct types of bone lesions that result from the overactivity of osteoclasts and are most often associated with chronic kidney disease (CKD). Despite their potential consequences, these conditions are poorly understood because of their rare prevalence and variability in their clinical manifestation. Canonically, OFC and Brown Tumours are caused by secondary hyperparathyroidism in CKD. Recent literature showed that multiple factors, such as hyperactivation of the renin-angiotensin-aldosterone system and chronic inflammation, may also contribute to the occurrence of these diseases through osteoclast activation. Moreover, hotspot KRAS mutations were identified in these lesions, placing them in the spectrum of RAS-MAPK-driven neoplasms, which were until recently thought to be reactive lesions. Some risk factors contributed to the occurrence of OFC and Brown Tumours, such as age, gender, comorbidities, and certain medications. The diagnosis of OFC and Brown Tumours includes clinical symptoms involving chronic bone pain and laboratory findings of hyperparathyroidism. In radiological imaging, the X-ray and Computed tomography (CT) scan could show lytic or multi-lobular cystic alterations. Histologically, both lesions are characterized by clustered osteoclasts in a fibrotic hemorrhagic background. Based on the latest understanding of the mechanism of OFC, this review elaborates on the manifestation, diagnosis, and available therapies that can be leveraged to prevent the occurrence of OFC and Brown Tumours.

Brown tumors in nuclear medicine: a systematic review

Brown tumors (BT) are abnormal bone-repair processes and a consequence of hyperparathyroidism. The diagnosis of these lytic lesions in nuclear medicine, while a challenge, is not so rare, because functional imaging is used both in the management of cancer and hyperparathyroidism. The main objective of this review is to summarize the knowledge and the evidence concerning BT and the different imaging modalities in nuclear medicine. A systematic review was performed in Embase, PubMed and Google Scholar from 2005 to 2022. We included articles describing BT in the following imaging modalities: [¹⁸F]-fluorodeoxyglucose PET/CT, [¹⁸F]-fluorocholine or [¹¹C]-fluorocholine PET/CT, [^99mTc]-Sestamibi scintigraphy, bone scan, [¹⁸F]-sodium fluoride PET/CT, [⁶⁸Ga]-FAPI PET/CT; [⁶⁸Ga]-DOTATATE PET/CT; [¹¹C]-methionine PET/CT. For each modality, appearance, avidity for radiotracer, available quantitative parameters and imaging evolution after parathyroidectomy were collected and analyzed. Fifty-two articles were included for a total of 392 BT lesions. If the diagnosis of BT is evoked on a known lesion, performing a [¹⁸F]-fluorocholine PET/CT imaging seems the most appropriate. In [¹⁸F]-fluorodeoxyglucose, [¹⁸F]-fluorocholine, [¹⁸F]-sodium fluoride PET/CT and bone scan, BT can mimic metastatic disease. BT uptakes appear reversible after parathyroidectomy, with a more or less rapid decrease depending on the imaging modality used.

Primary hyperparathyroidism-induced brown tumors caused by parathyroid carcinoma: a case report and literature review

Brown tumors represent a benign disease that is induced by primary or secondary hyperparathyroidism, with the pathological feature of osteitis fibrosa cystica. Primary hyperparathyroidism caused by parathyroid carcinoma resulting in brown tumors is extremely rare. Herein, we report the case of a 60-year-old male patient who was admitted for giant cell tumors of the bone with local pain and limited movement of the left knee joint. With early detection of multifocal osteolytic bone lesions, hyperparathyroidism (parathyroid hormone: 2365.00 pg/mL), and parathyroid cancer, the diagnosis of brown tumors was confirmed without any unnecessary or harmful interventions. Thereafter, he underwent parathyroidectomy, from which postoperative pathology confirmed parathyroid carcinoma, and total knee arthroplasty to restore movement of the knee joint. Seven months after surgery, the left knee joint had good range of movement. This case emphasizes that detecting patients’ parathyroid hormone levels should not be neglected when diagnosing multifocal osteolytic bone lesions. A comprehensive analysis combining clinical symptoms, imaging, and laboratory tests is conducive to accurate disease assessments and avoiding unnecessary or even survival-impairing surgery. However, when the tumor involves a large joint or seriously affects joint movement, surgery may be worth considering.