Osteolytic lesions (brown tumors) of primary hyperparathyroidism misdiagnosed as multifocal giant cell tumor of the distal ulna and radius: a case report

Abstract

BackgroundBrown tumors represent a rare clinical manifestation reported in approximately 3% of patients with primary hyperparathyroidism and correspond to radiologically osteolytic lesions with well-defined borders in different parts of the skeleton.Case presentationWe report the case of a 53-year-old white man who presented to our hospital with osteolytic lesions of his distal ulna and radius, causing pain and swelling of 2-month duration. A subsequent biopsy revealed histological features consistent with giant cell tumor and a complete resection of his distal ulna was followed, along with curettage and cementoplasty of the distal radial metaphysis. Two weeks later, he was re-admitted with diffuse musculoskeletal soreness, anorexia, constipation, nausea, and localized abdominal pain and multiple osteolytic lesions on plain radiographs. A histopathological examination of the ulna and radius specimens showed similar findings and, given the multifocality, brown tumors related to primary or secondary hyperparathyroidism was included in the differential diagnosis. A laboratory examination showed high total serum calcium (14.5 mg/dl) and low serum phosphorus and 25-hydroxyvitamin D levels. Primary hyperparathyroidism was suspected and confirmed by the elevated parathyroid hormone levels of 1453 pg/mL. At radiological work-up, using computed tomography, ultrasonography, and parathyroid subtraction technetium-99m sestamibi scintigraphy, a 4.5 × 2.5 × 3.2 cm mass emanating from the right lobe of his thyroid gland was detected, displaying extensive uptake in the right lower parathyroid gland. After appropriate medical support including hyperhydration and high doses of diuretics and diphosphonates, his laboratory profile normalized and he underwent total thyroidectomy with removal of the parathyroid glands. Our patient is now recovering 12 months after surgery, with normal values of serum parathyroid hormone and calcium levels. The lytic bone lesions have almost disappeared and no other additional orthopedic intervention was necessary.ConclusionsThe present case report emphasizes the need of inclusion of brown tumors in the differential diagnosis of multifocal osteolytic bone lesions, in order to avoid harmful surgical interventions. Laboratory testing of serum phosphate, calcium levels, and parathyroid hormone levels should always be included in the routine survey of patients with multifocal osteolytic lesions.

Brown tumor of the iliac crest initially misdiagnosed as a giant cell tumor of the bone

“…One of the best ways to distinguish BTs from other giant cell-containing bone lesions is through biochemical workup: hypercalcemia with elevated PTH levels in the presence of a giant cell-rich osteolytic lesion is highly suggestive of the diagnosis of BT. However, it is to keep in mind that there are a few cases reporting the concomitant presence of a GCT and PHPT (3,7). (3,7,8,9).…”

Severe Primary Hyperparathyroidism Caused by Parathyroid Carcinoma in a 13‐Year‐Old Child; Novel Findings From HRpQCT

“…In both studies, (33,34) there was no report of any osteolytic lesions, which may also be explained by this mechanism, but is most likely caused by the higher PTH levels attributed to the carcinoma versus parathyroid adenomas noted in published adult studies. (39)(40)(41) It is important to note, however, that the interpretation of HRpQCT bone properties in the context of healthy controls is currently limited for the HRpQCT version 2 of the scanner. The available normative data for children in the literature have only reported results from version 1 scanners, (42) which use a slightly lower resolution (82-μm isotropic voxel size) and yield multiple parameters that are not directly measured, but are derived from bone volume fraction and trabecular density.…”

A Benign Pathology Mimicking Multiple Bone Metastasis on F-18 FDG-PET/CT: Brown Tumor

“…Histopathologically, the differential diagnosis of these two tumors may not be made. Clinical and laboratory findings of hyperparathyroidism also should be definitely evaluated (10). The treatment of Brown tumor is partial or complete resection of the parathyroid gland.…”

“…The treatment of Brown tumor is partial or complete resection of the parathyroid gland. Spontaneous tumor regression is followed by the operation (10). The treatment of GCT is a surgical excision of the tumor.…”