TTR and cutaneous mastocytosis: Cardiac amyloidosis (CA) is characterized by the extracellular deposition of amyloid fibrils in the heart with the distinctive histological property of green birefringence when viewed under cross polarized light microscopy after staining with Congo red.1,2 There are two main types of CA, namely transthyretin (TTR) cardiomyopathy (ATTR-CM) and light chain (AL) cardiomyopathy (AL-CM).