Abstract ID: 26-506
Successful management of bilateral orbital metastases from invasive lobular breast cancer with abemaciclib and letrozole: a case report
Author: Catarina Barão Base Hospital / Institution: ULS São José
Presentation Type: ePoster Presentation
Purpose
To report a rare case of synchronous bilateral orbital metastases as the presenting manifestation of bilateral hormone receptor-positive (HR+)/HER2-negative (HER2-) lobular breast carcinoma, and to describe the sustained response to first-line treatment with abemaciclib and letrozole.
Methods
A 51-year-old woman presented with progressive right periorbital edema, pain, and restricted ocular motility. Orbital imaging demonstrated bilateral intra- and extraconal infiltrative lesions. An orbital biopsy was performed, and histopathological and immunohistochemical analyses were conducted. A systemic evaluation, including breast imaging, was subsequently undertaken. Clinical course, treatment, and follow-up data were reviewed.
Results
Histopathology demonstrated moderately differentiated lobular carcinoma cells within fibrous tissue and mild chronic inflammatory infiltrate. Tumor cells were positive for GATA3 and CK7, with 100% estrogen receptor expression. Systemic evaluation confirmed bilateral multicentric HR+/HER2- lobular breast carcinoma with synchronous bilateral orbital metastases. Treatment with abemaciclib (150 mg twice daily) and letrozole (2.5 mg daily) was initiated but temporarily interrupted because of toxicity. Therapy was resumed after two weeks with reduced-dose abemaciclib (100 mg twice daily) combined with letrozole, with acceptable tolerance. Nearly two years after diagnosis of inoperable metastatic disease, the patient remains clinically stable without evidence of progression.
Conclusion
Bilateral orbital metastases may represent the first manifestation of occult lobular breast carcinoma. This case highlights the importance of considering metastatic breast cancer in the differential diagnosis of atypical orbital inflammation. The combination of abemaciclib and letrozole demonstrated a remarkable and durable response, suggesting that CDK4/6 inhibitors may represent an effective therapeutic option in selected patients with orbital metastatic disease from HR+/HER2- breast cancer.
Additional Authors
| First name | Last name | Base Hospital / Institution |
|---|---|---|
| Miguel | Lopes | ULS São José |
| Nuno | Alves | ULS São José |
| Ana Teresa | Miranda | ULS São José |
| Catarina | Mota | ULS São José |
| Ana | Duarte | H. CUF Descobertas |