Question category: Endocrinology
A 42 year old female presents with malaise, night sweats and weight loss. She has also noticed tender bruise like lesions on her shins. A CXR reveals bilateral hilar lymphadenopathy. She has also noticed polydipsia, polyuria and constipation over the last few weeks and bloods reveal hypercalcaemia. Given the most likely diagnosis, what is the cause of her hypercalcaemia?