Improvement of Giant Cell Lesions of the Jaw Treated With High and Low Doses of Denosumab: A Case Series.

Giant cell tumors (GCTs) and central giant cell granulomas (CGCGs) are aggressive lesions that appear in the jaw. These lesions occur in the second and third decades of life and often arise in the mandible. Clinical manifestations of these lesions vary from asymptomatic to symptomatic tooth displacement with cortical perforation. GCTs, which are characterized by multinucleated osteoclast-type giant cells that express receptor activator of nuclear factor-κB (RANK) ligand, rarely present in the jaw and have overlapping histopathologic features with CGCGs, which are composed of fibroblastic stromal cell lesions. GCTs and CGCGs have overlying histopathologic features that make distinction between the two challenging. There is a real controversy as to whether giant cell tumors and central giant cell granulomas are in fact, one and the same lesion. The majority of GCTs occur in the long bone, with surgery being the typical therapeutic option. Denosumab as a treatment modality is a fairly new concept that has been used effectively in GCTs affecting long bones. There is less experience, however, with its use for jaw lesions. This seven-case series describes the effective use of both low-dose and high-dose denosumab in the treatment of GCTs and CGCGs affecting the jaw and special dosing considerations for younger patients who present with disease. © 2017 The Authors. JBMR Plus Published by Wiley Periodicals, Inc. on behalf of the American Society for Bone and Mineral Research.

Osteoporosis as the sole manifestation of systemic mastocytosis in a young man.

OBJECTIVE: To highlight the difficulty involved in making a diagnosis of systemic mastocytosis (SM) when it manifests solely as osteoporosis. METHODS: We present a detailed case report and review the literature regarding the work-up of secondary osteoporosis and the diagnosis and treatment of SM. Other cases of SM presenting as osteoporosis in male patients are also described. RESULTS: A 35-year-old man presented with back pain after weight lifting and was diagnosed with a T7 vertebral compression fracture. A dual-energy x-ray absorptiometry scan resulted in a T-score of -3.2 in the spine and of -1.9 and -2.4 in the hip and femoral neck areas, respectively. Results of standard tests for secondary osteoporosis including calcium, phosphorus, 25-hydroxyvitamin D, kidney and liver function, thyroid function, testosterone level, and midnight salivary cortisol were normal. Further testing revealed a high serum tryptase level of 26.8 µg/L (reference range, <11.4) and elevated urinary histamine at 39.1 µg/g creatinine (reference range, <35). Bone marrow biopsy confirmed the diagnosis of mastocytosis. CONCLUSION: The rare diagnosis of SM is difficult when there is little clinical suspicion and remains a challenge to endocrinologists and other physicians. The condition should be suspected in young male patients with no other obvious cause of osteoporosis.