Fig. 1

Postoperative follow up neck CT. a b An enlarged mass considered as transplanted parathyroid tissue (2.0 × 1.7 × 1.7 cm in size) in the clavicular head of left sternocleidomastoid muscle (white arrow). Enhanced Neck CT performed 3 years after total parathyroidectomy with auto-transplantation. (a) Axial view; (b) Coronal view; (c)(d) Compared with 3 years after surgery, a more enlarged mass with internal dense calcification (2.5 × 2.0 × 2.0 cm in size) was found on the clavicular head of left sternocleidomastoid muscle (black arrow). Enhanced Neck CT performed 8 years after total parathyroidectomy with auto-transplantation. (c) Axial view; (d) Coronal view