```xml
<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<ns4:query_definition xmlns:ns2="http://www.i2b2.org/xsd/cell/crc/psm/1.1/" xmlns:ns4="http://www.i2b2.org/xsd/cell/crc/psm/querydefinition/1.1/" xmlns:ns3="http://www.i2b2.org/xsd/cell/crc/psm/analysisdefinition/1.1/">
    <query_name>Principal Diagn@21:33:21</query_name>
    <query_timing>ANY</query_timing>
    <specificity_scale>0</specificity_scale>
    <panel>
        <panel_number>1</panel_number>
        <panel_timing>ANY</panel_timing>
        <panel_accuracy_scale>100</panel_accuracy_scale>
        <invert>0</invert>
        <total_item_occurrences>1</total_item_occurrences>
        <item>
            <hlevel>3</hlevel>
            <item_name>Malignant neoplasms</item_name>
            <item_key>\\i2b2_DIAG\i2b2\Diagnoses\Neoplasms (140-239)\Malignant neoplasms (140-208)\</item_key>
            <item_icon>FA</item_icon>
            <tooltip>Diagnoses \ Neoplasms \ Malignant neoplasms</tooltip>
            <class>ENC</class>
            <constrain_by_modifier>
                <modifier_name>Principal Diagnosis</modifier_name>
                <modifier_key>\\i2b2_DIAG\Principal Diagnosis\</modifier_key>
                <applied_path>\i2b2\Diagnoses\Neoplasms (140-239)\%</applied_path>
            </constrain_by_modifier>
            <item_is_synonym>false</item_is_synonym>
        </item>
    </panel>
</ns4:query_definition>

```

I want to find all patients with a principal diagnosis of malignant neoplasms within the specified date range, including all subcategories under the broader category of malignant neoplasms. The specificity scale is set to 0, meaning the results will include all possible matches, and the panel accuracy scale is set to 100, indicating the highest level of accuracy. The query is not inverted, and only one occurrence of the specified diagnosis is required for a patient to be included in the results.