In this retrospective study, investigators examined the presence of a triangle-shaped tissue resembling a wedge in patients with biopsy-proven lacrimal gland disease.
Study design
MRI and CT images were obtained from 116 patients with a history of lacrimal gland carcinoma, lymphoma or dacryoadenitis treated at a single center.
The senior author then assessed a randomized, masked selection of images to determine the presence of a “wedge sign” in either the lateral or superior space. The authors defined the wedge as posterior extension of a clear lateral triangle of tissue between the lateral rectus and neighboring orbital wall.
Outcomes
The presence of a lateral wedge was most common in patients with carcinoma (41%), followed by lymphoma (30%) and dacryoadenitis (15%). The prevalence of a lateral wedge in those with malignant lesions (either carcinoma and lymphoma, 36%) was significantly higher than those with benign dacryoadenitis (P=0.029).
A similar pattern was observed for the superior wedge, which was found in 26% and 16% of patients with carcinoma and lymphoma, respectively. The combined incidence of the superior wedge in malignant disease was significantly higher than that of dacryoadenitis (P=0.029).
Limitations
The main limitations of the study include its retrospective design. Additionally, the grading is subjective and based on a single grader. Measurement-based grading would offer a more objective method to interpret scans.
Clinical significance
In general, lacrimal gland pathology can be separated into carcinomas, lymphomas, or inflammations. Diagnosis usually involves clinical history and signs, imaging and biopsy.
The authors found that the presence of the "wedge sign" is more common in lacrimal gland malignancies, and when seen, a life-threatening pathology should be suspected and biopsy should be performed urgently. When associated with dacryoadenitis, of the wedge indicated a severe inflammation or systemic vaculitides such as granulomatosis with polyangiitis, as opposed to more chronic or mild forms of inflammation.