Multiple brown tumors with Tc-99m MDP superscan appearance and negative Tc-99m MIBI uptake

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.

Localization of Brown Tumors With 18F-Fluorocholine PET/CT Imaging in Severe Primary Hyperparathyroidism

ABSTRACT

We present the case of a 68-year-old woman with a painful tibial tumor and fatigue. Histology and laboratory studies were consistent with a brown tumor secondary to initially unrecognized, severe primary hyperparathyroidism. 18F-fluorocholine PET/CT revealed a large hypermetabolic parathyroid mass and multiple bone foci considered as brown tumors. Unilateral neck exploration confirmed a large parathyroid adenoma. Serum calcium and parathyroid hormone levels normalized quickly, and symptoms subsided gradually after parathyroidectomy. Brown tumors are a rare complication of severe hyperparathyroidism. 18F-fluorocholine PET/CT allows the localization of parathyroid adenomas and brown tumors, and can be used as a single imaging modality.

Primary hyperparathyroidism presenting with sudden onset paraplegia

A 48-year-old female with long-standing type 2 diabetes mellitus presented with acute onset of bilateral lower limb weakness. She had been previously well and denied any constitutional symptoms. Physical examinations revealed generalized lower limb weakness with bilateral lower limb hypotonia, power of 0 over 5, reduced deep tendon reflexes, and loss of peripheral sensations up to the level of T10. Upper limb functions were normal. Rectal examination showed a lax anal tone and reduced anal grip. Blood investigations showed elevated serum alkaline phosphatase, corrected serum calcium, and parathyroid hormone. Magnetic resonance imaging of the spine revealed an expansile mass at the posterior element of the ninth thoracic vertebrae, causing spinal compression with possible impingement of the right T9 exiting spinal nerve. An urgent surgical decompression and tissue biopsy were performed for stabilization of the spine. Intraoperative findings included spinal cord compression secondary to an epidural tumour mass extending from T9 to T10 disc levels. Histopathological analysis showed a giant cell tumour of the spine. A ^99mTc Sestamibi-SPECT parathyroid scintigraphy showed an ectopic parathyroid adenoma at the left suprasternal region. A diagnosis of Brown tumour secondary to ectopic parathyroid adenoma was made. She underwent an exploratory parathyroidectomy procedure with removal of the ectopic parathyroid gland, which resulted in a normalization of the serum calcium and parathyroid hormone. Unfortunately, her lower limb functions did not return to normal, and she remained paraplegic at 6 months postoperatively.

Multiple brown tumors-Forgotten pathology in times of calcimimetics: A case report and literature review

Multiple brown tumors represent a rare variant of osteitis fibrosa cystica. Brown tumors are associated with primary, secondary, or tertiary hyperparathyroidism. Brown tumors have been reported in patients with chronic kidney disease resulting in mineral and bone disorders. Chronic kidney disease resulting in mineral and bone disorder is a result of increased osteoclast activity and excessive production of parathormone due to parathyroid gland hyperactivity. Brown tumors are frequently overlooked in patients with end-stage renal disease since calcimimetics and vitamin D analogs were introduced as pharmacological therapy for secondary hyperparathyroidism. We present a case of a 79 year-old pre-dialysis woman, with multiple brown tumors secondary to a parathyroid adenoma despite being treated with cinacalcet for secondary hyperparathyroidism. In addition, we review the corresponding literature.

18F-Fluorocholine PET/CT Imaging of Brown Tumors in a Patient With Severe Primary Hyperparathyroidism

Brown tumors are rare skeletal anomalies occurring in patients with hyperparathyroidism and exposing patients to pathological fractures. We report the case of a 26-year-old woman with severe primary hyperparathyroidism (calcemia, 2.9 mmol/L; parathyroid hormone, 59 pmol/L) who underwent F-fluorocholine (FCH) PET/CT before parathyroidectomy. FCH PET localized the hyperfunctioning parathyroid gland and showed multiple foci in correspondence with bone lytic lesions on CT. Those lesions were not visible on the Tc-MIBI dual-phase scintigraphy. The pathology of one of the FCH-positive bone lesions corresponded to a brown tumor related to hyperparathyroidism.