Presentation
Chronic right shoulder pain and intermittent weakness.
Patient Data
Cortical thickening at the lateral aspect of right humerus, which is at the expected site of deltoid tuberosity (for deltoid muscle insertion), with intracortical lucency (better seen in zoom in image).
Annotated image showed the intracortical lucency within the thickened cortex at the deltoid tuberosity.
Case Discussion
Pseudotumor deltoideus is a normal anatomic variant seen at the deltoid insertion site in proximal humerus. This term was first introduced in 2001 by Morgan 1.
The typical radiographic features are focal area of cortical irregularity with central lucency at deltoid insertion site 1.
It is one of the "no touch" bone lesion where biopsy should not be performed and unnecessary interventions can be avoided.
The major differential diagnoses are
fibrous cortical defect - radiographic appearance is quite similar to pseudotumor deltoideus, but fibrous cortical defect would extend beyond the deltoid insertion site. It appears as well defined cortical lytic lesion with thinned cortical expansion.
Calcific tendinitis - focal calcified deposits in the adjacent soft tissue with cortical thickening and irregularity. The absence of soft tissue component and calcification in this case exclude this differential diagnosis.
Avulsion injury - acute avulsion usually has normal radiograph. For chronic avulsive injury, cortical defect with soft tissue swelling and periosteal reaction may be observed.
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