Background: Osteoid osteoma is a benign tumor, predominantly affects the younger age group with characteristic nocturnal symptoms, relieved by rest and anti-inflammatory drugs. It can affect any bone; the most common site is shaft of long bones of lower limb (90%). It is quite uncommon to find osteoid osteoma in acromion of scapula. Case Presentation: We describe a case of 46 year old male, presented with pain in left shoulder that simulated left shoulder joint arthritis. The diagnosis of osteoid osteoma involving acromion of scapula was made on bone scan. Tc99m MDP SPECT-CT images showed a distinct focus of increased uptake in the acromion of left scapula with characteristic central lucent nidus on CT images. Conclusion: Though Osteoid osteoma in acromion is very rare, shoulder pain in middle age group, when evaluated on nuclear medicine floor, should be evaluated with correlative SPECT-CT images to rule out such rare bony pathologies.

Keywords: Osteoid osteoma, acromion, bone scan, SPECT/CT, case report