Solitary phalangeal brown tumour in primary hyperparathyroidism: Report of a rare presentation
A 39-year-old male was referred to a hand surgeon at our hospital with history of swelling in the right thumb of 2 years duration. It was noticed following a trivial trauma and it had been gradually increasing in size with no associated constitutional symptoms. On clinical examination, there was grade 4 clubbing of right thumb []. A plain radiograph of the hand showed an expansile lytic lesion involving the distal phalanx of the thumb with marked cortical thinning and focal defects in the cortex. Subperiosteal bone resorption was seen in the phalanges, particularly along the radial aspects of the middle phalanges of the middle and index finger and also along the phalangeal tufts []. In view of elevated serum alkaline phosphatase and with a suspicion of solitary bone metastasis, Tc 99m methylene diphosphonate bone scintigraphy was performed. Bone scintigraphy revealed generalized intense tracer uptake in the axial and appendicular skeleton including the costal cartilages []. Increased tracer uptake was noted in the distal phalanx of right thumb [] and both scapulae. There was stasis of tracer in both kidneys. Based on these findings, the possibility of hyperparathyroidism was suggested. Further evaluation revealed elevated serum calcium, 12.5 g% and serum PTH levels, 1,821 pg/ml.\nRadiograph of the lumbar spine showed diffuse osteopenia. Bilateral stag horn renal calculi were also noted []. Lateral radiograph of the skull showed granular deossification giving the classical “salt and pepper” appearance and loss of sharp definition of the inner and outer tables []. Tc 99m sestamibi parathyroid scintigraphy [] demonstrated a functioning parathyroid adenoma in the region of the inferior pole of left lobe of thyroid, which was confirmed by single-photon emission computed tomography [Figure and ] with associated tracer uptake in the distal phalanx of the right thumb [] confirming the diagnosis of primary hyperparathyroidism due to left inferior parathyroid adenoma and brown tumor right thumb []. Ultrasound examination of the neck revealed a 10 cm × 6 mm sized well-defined ovoid hypoechoic lesion at the level of the lower pole of left lobe of thyroid, but lateral to the carotid artery, between the common carotid artery (CCA) and internal jugular vein (IJV). There was marked vascularity within the lesion on Doppler image []. This corresponded to the lesion seen on the Tc 99m Sestamibi scan and an ectopic location of parathyroid adenoma was considered.\nHe underwent excision of left inferior parathyroid adenoma. The operative findings revealed 2 cm × 1 cm lobulated left inferior parathyroid adenoma in ectopic location within left carotid sheath between the carotid artery and IJV butting the vagus nerve and also a 1.5 cm whitish firm nodule superior to it which was thought likely to be ectopic thymic remnant. The findings were confirmed by histopathology. His post-operative corrected serum calcium level was within normal limits (8.3 mg%). His follow-up after 1 year revealed 50% reduction in the size of the thumb swelling and his follow-up serum calcium was 9.4 mg%.