A 60 year old female develops bilateral cicatrisation of the conjunctiva. The patient undergoes a conjunctival biopsy for direct immunofluorescence (DIF) and the results are shown in Figs 1,2 and 3.
Fig 1 IgA
Fig 2 IgG
Fig 3 C3
1. What is the clinical differential diagnosis?
2. What do the DIF images show?
3. What is the likeliest diagnosis?
4. What is the histological differential diagnosis?
5. How should conjunctival biopsies destined for DIF be sent to the path lab?
6. Should a biopsy for formalin also be taken at the same time? If yes-why?
1. Trauma; Infection; Allergic; Drugs; Mucocutaneous disorders; Immunobullous disorders; Systemic autoimmune disorders; Neoplastic; MMP/OCP.
2. Linear IgG, IgA and granular to linear C3 along the epithelial basement membrane.
4. Paraneoplastic OCP/MMP, drugs, systemic autoimmune conditions
5. Michel’s aqueous medium or equivalent or fresh in saline gauze
6. Yes—to look at inflammatory cell mix (eg eosinophils could indicate rosacea or allergic KC, granulomas in infectious or sarcoid) and exclude dysplasia and malignancy.