Three Rare Concurrent Complications of Tertiary Hyperparathyroidism: Maxillary Brown Tumor, Uremic Leontiasis Ossea, and Hungry Bone Syndrome

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.

The value of integration of bone scan and targeted SPECT/CT in diagnosis of primary hyperparathyroidism with multiple bone brown tumor

Although parathyroid bone disease is rarely seen nowadays, skeletal manifestation can be the first sign of hyperparathyroidism (HPT) in some clinical practice. Nevertheless, the diagnosis of HPT is often overlooked. We describe three cases of multiple brown tumors (BT) in which bone pain and destruction were the first symptoms that masqueraded as a malignancy. However, according to the results of bone scan and targeted single-photon emission computed tomography/computed tomography (SPECT/CT), we considered BTs as the diagnosis in all of three cases. The final diagnoses were confirmed by laboratory tests and post-parathyroidectomy pathology. Parathyroid hormone (PTH) is significantly elevated in primary hyperparathyroidism (PHPT) as we know. However, such elevation is virtually never seen in malignancies. Diffuse or multiple foci of tracer uptakes in the bone scan were always seen in bone metastasis, multiple myeloma, and other bone neoplasm. When patients visited nuclear medicine for first consultation without biochemical results, radiological evidence from planar bone scan and targeted SPECT/CT can help in distinguishing the skeletal diseases. Lytic bone lesions with sclerosis, intra-focal or ectopic ossification and calcification, fluid-fluid level, and distribution of the lesions may be helpful in the differential diagnosis in these reported cases. In conclusion, when patients present with multiple foci of uptake on bone scan, targeted SPECT/CT is acquired for suspicious lesions, which can increase the diagnostic sensitivity and reduce unnecessary interventions and treatment. Moreover, BTs should be always kept in differential diagnosis of multiple lesions without a conclusive primary tumor.

Forestalling Hungry Bone Syndrome after Parathyroidectomy in Patients with Primary and Renal Hyperparathyroidism

Hungry bone syndrome (HBS), severe hypocalcemia following parathyroidectomy (PTX) due to rapid drop of PTH (parathormone) after a previous long term elevated concentration in primary (PHPT) or renal hyperparathyroidism (RHPT), impairs the outcome of underlying parathyroid disease.

OBJECTIVE

overview HBS following PTx according to a dual perspective: pre- and post-operative outcome in PHPT and RHPT. This is a case- and study-based narrative review.

INCLUSION CRITERIA

key research words "hungry bone syndrome" and "parathyroidectomy"; PubMed access; in extenso articles; publication timeline from Inception to April 2023.

EXCLUSION CRITERIA

non-PTx-related HBS; hypoparathyroidism following PTx. We identified 120 original studies covering different levels of statistical evidence. We are not aware of a larger analysis on published cases concerning HBS (N = 14,349). PHPT: 14 studies (N = 1545 patients, maximum 425 participants per study), and 36 case reports (N = 37), a total of 1582 adults, aged between 20 and 72. Pediatric PHPT: 3 studies (N = 232, maximum of 182 participants per study), and 15 case reports (N = 19), a total of 251 patients, aged between 6 and 18. RHPT: 27 studies (N = 12,468 individuals, the largest cohort of 7171) and 25 case reports/series (N = 48), a total of 12,516 persons, aged between 23 and 74. HBS involves an early post-operatory (emergency) phase (EP) followed by a recovery phase (RP). EP is due to severe hypocalcemia with various clinical elements (<8.4 mg/dL) with non-low PTH (to be differentiated from hypoparathyroidism), starting with day 3 (1 to 7) with a 3-day duration (up to 30) requiring prompt intravenous calcium (Ca) intervention and vitamin D (VD) (mostly calcitriol) replacement. Hypophosphatemia and hypomagnesiemia may be found. RP: mildly/asymptomatic hypocalcemia controlled under oral Ca+VD for maximum 12 months (protracted HBS is up to 42 months). RHPT associates a higher risk of developing HBS as compared to PHPT. HBS prevalence varied from 15% to 25% up to 75-92% in RHPT, while in PHPT, mostly one out of five adults, respectively, one out of three children and teenagers might be affected (if any, depending on study). In PHPT, there were four clusters of HBS indicators. The first (mostly important) is represented by pre-operatory biochemistry and hormonal panel, especially, increased PTH and alkaline phosphatase (additional indicators were elevated blood urea nitrogen, and a high serum calcium). The second category is the clinical presentation: an older age for adults (yet, not all authors agree); particular skeleton involvement (level of case reports) such as brown tumors and osteitis fibrosa cystica; insufficient evidence for the patients with osteoporosis or those admitted for a parathyroid crisis. The third category involves parathyroid tumor features (increased weight and diameter; giant, atypical, carcinomas, some ectopic adenomas). The fourth category relates to the intra-operatory and early post-surgery management, meaning an associated thyroid surgery and, maybe, a prolonged PTx time (but this is still an open issue) increases the risk, as opposite to prompt recognition of HBS based on calcium (and PTH) assays and rapid intervention (specific interventional protocols are rather used in RHPT than in PHPT). Two important aspects are not clarified yet: the use of pre-operatory bisphosphonates and the role of 25-hydroxyitamin D assay as pointer of HBS. In RHPT, we mentioned three types of evidence. Firstly, risk factors for HBS with a solid level of statistical evidence: younger age at PTx, pre-operatory elevated bone alkaline phosphatase, and PTH, respectively, normal/low serum calcium. The second group includes active interventional (hospital-based) protocols that either reduce the rate or improve the severity of HBS, in addition to an adequate use of dialysis following PTx. The third category involves data with inconsistent evidence that might be the objective of future studies to a better understanding; for instance, longer pre-surgery dialysis duration, obesity, an elevated pre-operatory calcitonin, prior use of cinalcet, the co-presence of brown tumors, and osteitis fibrosa cystica as seen in PHPT. HBS remains a rare complication following PTx, yet extremely severe and with a certain level of predictability; thus, the importance of being adequately identified and managed. The pre-operatory spectrum of assessments is based on biochemistry and hormonal panel in addition to a specific (mostly severe) clinical presentation while the parathyroid tumor itself might provide useful insights as potential risk factors. Particularly in RHPT, prompt interventional protocols of electrolytes surveillance and replacement, despite not being yet a matter of a unified, HBS-specific guideline, prevent symptomatic hypocalcemia, reduce the hospitalization stay, and the re-admission rates.

A Rare Presentation of a Bi-Maxillary Brown Tumour due to Secondary Hyperparathyroidism

Brown tumours are localized bone lesions, seen in patients with high parathyroid hormone levels. This can be due to primary hyperparathyroidism, which occurs more often in neoplasms of the parathyroid gland or due to secondary hyperparathyroidism more often seen as a result of renal impairment. Facial involvement is rare, with most reports focusing on long and axial bones. However, the mandibular bone is often the only bone affected. Here, we report a rare case of a bi-maxillary attainment of brown tumour in a patient with secondary hyperparathyroidism due to chronic kidney disease.

Manifestations of hyperparathyroidism in the jaws: Concepts, mechanisms, and clinical aspects

Hyperparathyroidism is one of the most common endocrine disorders worldwide. In countries where routine biochemical screening is not common, symptomatic hyperparathyroidism predominates. Its manifestations include skeletal alterations, calcification of soft tissues, kidney stones, and functional alterations in other systems. Notably, jaw alterations can be the first clinical sign of hyperparathyroidism, including brown tumor, renal osteodystrophy, osteitis fibrosa, and leontiasis ossea, and knowing such conditions is of core importance for the multidisciplinary diagnosis and management of hyperparathyroidism. We aimed to perform a concise review, systematizing the concepts and mechanisms underlying hyperparathyroidism and associated gnathic alterations. In addition, a detailed description of the clinical aspects of the jaw manifestations is presented.