“Incomplete H Sign” in Sacral Insufficiency- A Rare Scintigraphic ‘H’ Sign Variant on Technetium-99m Methylene Diphosphonate (Tc-99m MDP) Bone Scan

A 52-year-old woman with a history of right breast carcinoma treated with surgery, chemotherapy, and radiotherapy presented with lower-back and gluteal pain following a minor fall. Tc-99m methylene diphosphonate (MDP) bone scintigraphy revealed intense horizontal linear uptake in the S3-S4 sacral segments, consistent with a sacral insufficiency fracture (SIF). SIFs are stress fractures commonly associated with osteoporosis and prior pelvic irradiation and may be difficult to detect on radiography. While the classic “Honda sign’’ is well recognised, variant scintigraphy patterns such as isolated horizontal uptake are less frequently described. Awareness of these patterns is essential to prevent misdiagnosis and unnecessary investigations.