Orbital myoepithelial carcinoma: implications for diagnosis and treatment strategies

Given the rarity orbital myoepithelial carcinoma (OMC) and the paucity of current evidence characterizing its clinical profile, this study aims to summarize the clinical features and prognostic outcomes of OMC.

This retrospective cohort study analyzed a consecutive series of 12 patients with histopathologically confirmed OMC managed at Beijing Tongren Hospital, Capital Medical University (January 1, 2000-December 31, 2024), with evaluation of demographic data, clinical features, imaging findings, histopathological features, treatment modalities, prognostic outcomes, and follow-up records, using progression-free survival and overall survival as primary outcome measures alongside clinical presentation and imaging study assessments.

Twelve patients (58.3% male, 7/12) were enrolled, with a mean age of 55.08 ± 14.46 years (range: 28-82). The mean age at initial detection of the tumor was 44.83 ± 18.89 years (range: 19-80). The most common initial presentation was abnormal globe position (41.7%). Tumors were generally large, with a maximum diameter ranging from 9.00 to 73.00 mm (median: 25.50 mm, IQR 18.75-35.25). Invasion into adjacent structures (sinonasal or intracranial) was observed in 41.7% (5/12) of cases. A history of prior neoplasms was noted in 83.3% (10/12) of patients, with pleomorphic adenoma (PA) accounting for 50%. MRI findings predominantly demonstrated lobulated cystic lesions with iso-intensity on T1-weighted imaging (T1WI), iso- to hyper-intensity on T2-weighted imaging (T2WI), and heterogeneous enhancement. CT scans revealed soft-tissue density masses, with calcifications in 25% of cases and bone destruction of 66.7% cases. Histopathologically, hemorrhage/necrosis was identified in 63.6% (7/11), and perineural invasion in 18.2% (2/11). During a mean follow-up of 6.56 ± 3.36 years (range: 1-12) in 9 patients, the overall survival rate was 77.8%, with two disease-specific deaths at 6- and 8-years post-diagnosis. The recurrence rate was 55.6%, and all three patients with a history of PA experienced recurrence. The progression-free survival rate was 44.4%, with a median survival time of 3 years (IQR 2-6).

OMC predominantly affects males, presents with large tumors prone to sinonasal/intracranial invasion and bone destruction, and carries a poor prognosis. Patients with PA-associated OMC exhibit exceptionally high recurrence rates, emphasizing the necessity of long-term postoperative surveillance.