Images in Pathology - Functioning Oxyphil Adenoma of Parathyroid

A 45-year-old lady presented with multiple joint pain for the last 6 years. She was initially treated for rheumatoid arthritis; as she did not respond, she was further evaluated and a diagnosis of hyperparathyroidism was made. At presentation, she had mild pedal oedema and tenderness over the twelfth thoracic and first lumbar vertebra