Unfortunately, formatting PivotTables with sparklines directly within Excel isn't currently possible. Sparklines are a limitation of Excel versions before 2010 and PivotTables require those later versions.

However, there are alternative approaches to achieve mini-trend visualizations within your PivotTables:

1. Conditional Formatting:

* Use conditional formatting to apply color coding or data bars based on the value or trend in your PivotTable cells. This can provide a visual cue of positive, negative, or flat trends.

2. Mini Charts within Cells:

* Consider using Excel's chart functionality to create small charts (like bar charts or line charts) directly within PivotTable cells. You can customize the chart size and format it to fit within the cell.

3. Separate Charts based on PivotTable Slicers:

* Utilize PivotTable slicers to filter your data and create separate charts for different categories. This allows you to see trends specific to each filtered view.

4. Export to Other Tools:

* Export your PivotTable data to other software like Google Sheets that supports sparklines alongside PivotTables.

5. Third-party Add-ins:

* Explore third-party add-ins specifically designed for Excel that might offer functionalities to integrate sparklines with PivotTables.

While sparklines within PivotTables aren't native to Excel, these alternative methods can still provide valuable visualizations of trends within your data.