In the sentence extracted from biomedical literature, identify all the chemical entities. The required answer format is the same sentence with HTML <span> tags to mark up specific entities. 
### Entity Markup Guides:
Use <span class="chemical"> to denote a chemical.

### Input Text: MATERIAL AND METHOD : A 40 - year - old woman presented with decreased sensation and paresthesia over her right lateral forearm ; the paresthesia had occurred after a steroid injection in the right lateral epicondyle 3 months before .
### Output Text:
MATERIAL AND METHOD : A 40 - year - old woman presented with decreased sensation and paresthesia over her right lateral forearm ; the paresthesia had occurred after a <span class="chemical">steroid</span> injection in the right lateral epicondyle 3 months before . 