Ultrasound-guided core-needle biopsy for extra-ocular orbital soft tissue tumours: a minimally invasive alternative to surgical biopsy.

Objective: To assess the feasibility, accuracy, and safety of ultrasound (US)-guided coaxial core-needle biopsy (CNB) for histomolecular diagnosis of extra-ocular orbital soft tissue tumours as a minimally invasive alternative to surgical biopsy.

Methods: This retrospective study was conducted at a single Comprehensive Cancer Center and included all consecutive patients referred to our center between 2015 and 2023 for the diagnosis and treatment of orbital soft tissue tumours. All patients underwent US-guided transconjunctival coaxial CNB using a semiautomatic 18-gauge biopsy gun. Pathological analysis included morphological analysis, immunostainings, and molecular biology techniques when required.

Results: A total of 26 patients were included consisting of 21 adults (median age: 64 years, range: 24-93 years), 1 adolescent (17 years), and 4 children (aged 4 weeks, 5 weeks, 26 months, and 6 years). Tumour largest diameters ranged from 11 to 57 mm (median 23 mm). The overall feasibility of CNB was 88% (23/26), and it was 100% (5/5) in children. The histological accuracy was 91% (21/23), and its safety was 96% (25/26). Molecular biology analyses were requested in 9 out of 23 cases and were successful in all instances. The final diagnoses included hematological malignancies (n = 8), carcinomas (n = 5), metastases (n = 4), sarcomas (n = 4), and benign mesenchymal tumours (n = 5).

Conclusions: This study supports the use of US-guided coaxial CNB for the pathological and molecular diagnosis of orbital soft tissue tumours in both children and adults. This technique shows promise as a minimally invasive alternative to open surgical biopsy.