Serum ACE 139 U/L (ref range 8-52)
Corrected serum Ca 3.73 mmol/L (ref range 2.10-2.60)
Patient proceeded to a right cervical lymph node biopsy:
Microscopic description: Sections of lymph node show extensive non-necrotising granulomatous inflammation. Multinucleated giant cells are present. There is no evidence of malignancy.
DIAGNOSIS: Non-necrotising granulomatous inflammation, consistent with sarcoidosis.
Sarcoidosis is a systemic disorder of unknown aetiology, characterised by non-caseating granulomas. Hypercalcaemia is often a feature secondary to extra-renal dysregulated production of calcitriol (1,25-VitD) by alveolar marcophages within the granulomas. Sarcoid granulomas also produce angiotensin-converting enzyme, with serum ACE levels elevated in 60% of patients. As a diagnostic test however, serum ACE lacks both sensitivity and specificity.
Common thoracic manifestations on HRCT are perilymphatic nodularity with an upper and mid zone distribution and hilar and mediastinal lymphadenopathy. The 1-2-3 sign refers to bilateral hilar and right paratracheal lymph node enlargement.