This 75-year-old gentleman presented with, and was admitted to hospital for acute pancreatitis. Investigations during his admission revealed an elevated calcium and PTH level. A parathyroid scan was performed and showed a high probability of a parathyroid adenoma, measuring 20 x 15 mm, involving station 1R. Given the unusual anatomical localization of this nodule it was suggested to proceed further with a high resolution contrast enhanced CT of the upper mediastinal region. This was performed and again showed a right paratracheal mass lesion measuring approximately 2.0 x 1.9 cm, which was thought to represent a parathyroid adenoma or an enlarged lymph node. The patient was booked for a right inferior parathyroidectomy.
Otherwise, the patient has known osteoporosis, no history of renal stones, and does complain of fatigue and anxiety. Past medical history is significant for coronary artery disease, hypertension, hyperlipidemia, gastroesophageal reflux disease, diabetes, and asthma.
What is the diagnosis?
What gives the cells this particular appearance?
What is the differential diagnosis?