Treatment with Trastuzumab Deruxtecan for Metastatic HER2-Low Scrotal Extramammary Paget’s Disease Involving Bone Marrow: A Case Study
By
Yi Bao
Lei Zhang
Fenfen Jiang
Juanfen Mo
September 1, 2026
Clinical Scorecard: Treatment with Trastuzumab Deruxtecan for Metastatic HER2-Low Scrotal Extramammary Paget’s Disease Involving Bone Marrow: A Case Study
At a Glance
Category Detail
Condition Scrotal Extramammary Paget’s Disease (EMPD) Key Mechanisms HER2-directed antibody-drug conjugate (Trastuzumab deruxtecan) Target Population Patients with metastatic scrotal EMPD and low HER2 expression Care Setting Oncology treatment centers
Key Highlights
Uncommon case of metastatic scrotal EMPD involving bone marrow Histopathological assessment confirmed stage IV disease Patient showed stable disease during treatment with trastuzumab deruxtecan HER2 expression was 2+, but FISH was negative for amplification Guideline-Based Recommendations
Diagnosis
Histopathological assessment and immunohistochemistry for HER2 expression Management
Consider trastuzumab deruxtecan for patients with low HER2 expression Monitoring & Follow-up
Monitor for disease progression and treatment-related adverse events Risks
Potential for severe thrombocytopenia and allergic reactions to treatment Patient & Prescribing Data
A 68-year-old male with metastatic scrotal EMPD
Patient received trastuzumab deruxtecan with stable disease despite significant tumor burden
Clinical Best Practices
Multidisciplinary team discussions for complex cases Regular monitoring of blood counts during treatment Consideration of immunotherapy-related adverse events in management Related Resources & Content
