Clinical and Histopathological study of corneal stromal dystrophies: a 15 year experience in Canada

Author Block: Dominique Geoffrion , Sabrina Bergeron, Dulce Lopez, Emily Marcotte, Siddharth Nath, Miguel Burnier.  McGill University.

Author Disclosure Block: D. Geoffrion:   None.  S. Bergeron:  None.   D. Lopez:  None.  E. Marcotte:   None.  S. Nath:  None.   M. Burnier:  None., Dominique Geoffrion: Not Current  Sabrina Bergeron: Not Current  Dulce Lopez: Not Current  Emily Marcotte: Not Current  Siddharth Nath: Not Current  Miguel Burnier: Not Current

Abstract Title: Clinical & Histopathological Study of Corneal Stromal Dystrophies: A 15-Year Experience in Canada

Abstract Body: Purpose:  Clinicopathologic findings can be ambiguous between granular corneal dystrophy (GCD) and Avellino (combined) dystrophy (also known as granular corneal dystrophy type II). Avellino dystrophy shares features of both lattice corneal dystrophy (LCD) and GCD. Clarifying the presentation and pathology is important to choose the appropriate management. The purpose was to determine the incidence of Avellino dystrophies in Canada.  Study Design:  Retrospective, comparative study  Methods:   A comparative analysis of 41 corneal specimens diagnosed with corneal dystrophy and collected from 2006 to 2021 at a single center. All corneas were retrieved from the MUHC-McGill University Ocular Pathology & Translational Research Laboratory at McGill University. Routine histopathologic staining and specific staining were performed to confirm the diagnosis and report incidence rates. Parametric and non-parametric tests were used for statistical purposes.  Results:  Mean age of patients was 58.6 ± 16.4 years, with 56% of males. The final pathological diagnosis was GCD in 10.3% (n=4), LCD in 48.7% (n=20), macular corneal dystrophy (MCD) in 12.8% (n=5) and Avellino 28.2% (n=12). Mean age at presentation for GCD was 62.8±3.4 years, LCD 61.7±3.7 years, MCD 41.2±8.6 years, and Avellino 59.8±4.4 years (P=0.323). Misdiagnosis between clinical and pathological features was highest among Avellino samples: 6 were misdiagnosed as LCD, one was incorrectly diagnosed as GCD, and the remaining corneas had an unknown diagnosis until definitive pathological diagnosis.  Conclusions:  This histopathological study confirms that lattice corneal stromal dystrophy is the most common corneal dystrophy in Canada, followed by the Avellino (combined) dystrophy. In comparison, macular corneal stromal dystrophy is most common in the Middle East. Histopathological examination with special stains is essential for the final diagnosis of corneal stromal dystrophies, in particular for the differential diagnosis between lattice and Avellino corneal stromal dystrophy.