Successful management of bilateral orbital metastases from invasive lobular breast cancer with abemaciclib and letrozole: a case report and literature review

Abstract

Breast cancer is a significant global health concern, contributing to substantial morbidity and mortality among women. Hormone receptor-positive (HR+)/HER2-negative (HER2-) breast cancer constitutes a considerable proportion of cases, and significant advancements have been made in its management. CDK4/6 inhibitors (CDK4/6is) are a new targeted therapy that has demonstrated efficacy in adjuvant, advanced and metastatic settings. The propensity of lobular breast carcinomas for estrogen-rich sites, such as periocular tissues and orbital fat, may explain their tendency for orbital metastases. Current treatment strategies for these cases are predominantly palliative, and the prognosis remains poor. This article presents a unique case of a 51-year-old female with progressive right periorbital edema, pain, and limited ocular motility. An imaging work-up showed bilateral intra and extraconal orbital infiltration, which was biopsied. The histopathologic analysis disclosed mild chronic inflammatory infiltrate with thickened fibrous tissue and moderately differentiated lobular carcinoma cells, positive for GATA3 and CK7 markers, with 100% of tumor nuclei expressing estrogen receptors (ER+). A systemic evaluation showed a multicentric nodular formation in both breasts. Further diagnostic assessments unveiled an HR+/HER2- bilateral lobular breast carcinoma with synchronous bilateral orbital metastases. Systemic treatment was initiated with abemaciclib 150mg twice daily and letrozole 2.5mg once a day. However, this regimen was interrupted due to toxicity. After two weeks, treatment was resumed with a reduced abemaciclib dose (100mg twice daily) alongside letrozole, with a reasonable tolerance. Nearly two years after the initial diagnosis of inoperable metastatic cancer, the patient remains on the same systemic treatment regimen with no signs of invasive disease. This case report is the first of a patient presenting with bilateral orbital metastases from bilateral lobular breast cancer, showing an impressive and sustained response to a first-line treatment regimen combining abemaciclib and letrozole. A literature review on bilateral orbital metastases from breast cancer is also presented.

Keywords: CDK4/6 inhibitor; abemaciclib; breast cancer; case report; letrozole; metastases; orbit; review.

Figure 1

Patient timeline.

Figure 2

Clinical presentation and orbital findings at the initial appointment. (Clinical pictures) Right inferior dystopia with restriction in extraocular elevation and adduction of the right eye. (Orbit Imaging) Orbit axial and coronal T1 MRI showing post-gadolinium enhancing lesions (intra and extra-conal), with mass effect and inflammatory changes of orbital fat.

Figure 3

Orbital biopsy. (Supero-left) Orbital biopsy comprised soft tissue and lacrimal gland fragments with infiltration by lobular breast carcinoma. (Supero-right) Lacrimal gland showing discohesive cells with nuclear atypia, many resembling signet-ring cells and containing intracellular mucin. (Infero-left) Thickened fibrous tissue where isolated cells and cell rows of similar histologic characteristics are identified. (Infero-right) Infiltrating cells exhibiting immunoreactivity for estrogen receptors, suggesting breast origin.

Figure 4

Orbital findings after sixteen months of systemic treatment and clinical presentation in 08/2023. (Orbit Imaging) Orbit axial and coronal T1 MRI showing imaging improvement in the orbital region, marked by permeabilization of bilateral intraorbital fat. (Clinical pictures) Significant clinical improvement in ocular movement restrictions, with only partial limitation remaining on right adduction.