Hyperparathyroidism is the most common endocrine disease after diabetes and thyroid problems. The incidence can be as high as 1/500 to 1/1000. It is mostly seen in postmenopausal women, between the fourth and sixth decades of life. It can be caused by a solitary adenoma (80–85%), multiple adenomas (5%), parathyroid hyperplasia (10–15%), and carcinoma (< 1–5%) of the parathyroid glands [7].
As a result of a continuous increase in PTH, a generalized loss of lamina dura, giant cell granulomas, and demineralization are seen radiologically. As a result of progressive demineralization, decreases in the thickness of buccal cortical plates, mandibular inferior cortex, and trabeculation are observed. Similarly, radiolucencies are observed with a generalized demineralization of the mandibular inferior cortex and sinus wall thickness [9, 10].
As a result of secondary osteoporosis development due to increased parathormone levels, bone pain, pathological fractures can be observed. In our case, the patient applied to our clinic due to generalized and progressive pain at the jawbones [11].
One of the clinical features caused by hyperparathyroidism is Brown Tumors. The incidence of these lesions in primary hyperparathyroidism was approximately 3%, and in secondary hyperparathyroidism, it was 2%. Lamina dura loss and internal/external root resorption can also be observed in advanced stages of the disease [7]. In this case, radiographically 31 × 49.2 mm dimensions, irregular limited, extraoral swelling, brown tumor-like radiolucent formation observed in the maxillary region, generalized lamina dura losses, external root resorptions were observed. In the occlusive plan of the CT scans taken, destruction was seen in the buccal cortical bone.
Normocalcemic hyperparathyroidism occurs with PTH elevation, which is not linked to any other reasons. Like in our case, normal calcium levels, low or normal phosphorus levels are monitored. In the literature, 7 brown tumor cases caused by normocalcemic hyperparathyroidism have been reported [12]. Although the prevalence of this disease was reported between 0.4 and 3.1%, it was not fully determined [1]. Many unanswered questions remain about the effect of normocalcemic PHPT on target organs and their epidemiology. In this case, the literature was investigated about whether the patient had a connection to multiple sclerosis, after the diagnosis of brown tumor, which was followed up with normocalcemic hyperparathyroidism, but no obvious results were found. However, it has been reported that IL-17a, which is increased through T-helper, acts by different mechanisms in both diseases.
MS seen at our patient is a chronic autoimmune central nervous system (CNS) disease characterized by inflammation, demineralization, and axon damage. Of MS patients, 85% develop ataxia, which can be cerebellar, sensory, or mixed type and may be associated with vertigo. It is rarely seen as a single symptom and usually occurs with muscle weakness and spasticity [12]. In the literature research, it was learned that the bone destruction mechanism of parathormone is caused by the secretion of IL-17a and in the formation of MS, it was learned that the elevated IL-17a level was an effective mediator. However, studies have not found any research on the exacerbation of bone lesions between multiple sclerosis and hyperparathyroidism [13].
The radiological properties of normocalcemic PHPT are similar to primary hyperparathyroidism findings, and osteopenia is common [11].
The first step in the treatment of Brown tumors due to hyperparathyroidism is to adjust the vitamin D level of HPT or partial tumor resection (PTx). After this treatment, the lesion is expected to shrink and PTH levels to normalize. However, in some cases, an increase in tumor sizes can be observed even after PTx. In such cases, an average of 1 or 2 years of follow-up is recommended after resection of the tumor. If symptoms are observed in the patient after 1 or 2 years of follow-up, surgical resection and decompression of brown tumor should be considered. Biopsies after resection reported the giant cells and an increase in osteoblastic activity and bone production. In some large lesions, resection can be considered after the PTH level is normalized and the lesion dimensions are reduced by intralesional steroid injection in the follow-up of the lesion [14].
However, the question mark here is that the increased IL-17a level in Brown Tumor is talking about increasing the osteoporotic state, while the effect of steroids used to increase this situation is unknown. In this case report, the preliminary diagnosis made entirely with radiological findings was confirmed by pathology, and the patient was consulted to the endocrinology department for the necessary treatment. The importance of radiological evaluation is high in such destructive lesions. In the literature, it was stated that only the lesions regressed as a result of the treatment [14]. However, there is a need for studies in which the results of the treatment can be shown radiologically. Thanks to these studies, the difference in bone density with normal bone can be determined and information about recurrence rates can be obtained. In addition, the success rate of the treatment according to the size of the lesion can be supported by radiological studies.
The radiologic similarities of brown tumors and other bone tumors make it difficult to reach a correct diagnosis. A solitary bone lesion of a brown tumor may be difficult to differentiate from an aneurysmal bone cyst, giant cell tumor, solitary bone cyst, and giant cell reparative granuloma [9]. Bone metastases or multiple myeloma may be considered primarily in multifocal osteolytic lesions, especially in cases where serum calcium levels are normal, as in our case. The use of extra radiological examinations at the diagnosis can be beneficial in these cases. One study showed that brown tumors were one of the few lesions that showed osteolytic appearance on radiographs and short T2 on MR imaging, but only 13 cases were found with an MR imaging of the brown tumor in the same study [15]. Only 6 of the 13 cases were published in a radiological journal [9]. In our case, MRI was not performed because access to the MRI device was difficult and expensive. However, there is a need for studies using MR imaging techniques in the diagnosis and treatment stages of the brown tumor seen in the jawbones.
As a result, the importance of the pre-diagnosis placed with radiological findings is stated in this case report and it is seen that it accelerates diagnosis and treatment in terms of PTH. When an irregular deconstructive lesion is detected in the radiological maxilla or mandibula, a detailed anamnesis should be taken. Even if serum calcium levels are normal, it is important to investigate serum parathormone level and evaluate other radiological findings of PTH instead of initially suspecting a malign lesion. In future studies, it is clear that the relationship between the presence and exacerbation of bone lesions in multiple sclerosis and hyperparathyroid patients will facilitate the treatment and follow-up process of these patients. In addition, more studies on radiological findings in the treatment process are needed to facilitate patient follow-up during treatment.
