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

### Input Text: We studied the clinical and radiological features in 81 patients from the literature and 5 own patients trying to identify distinct subgroups .
### Output Text:
We studied the clinical and radiological features in 81 patients from the literature and 5 own patients trying to identify distinct subgroups . 