Pathomorphosis of eyelid tumor pathology in demodectic infection

Abstract

Background. Pathological changes in the tissues of the oculo-conjunctival region caused by the activity of the Demodex mite is represented by the development of inflammatory process. On detection of the parasite on eyelashes, the presence of the Demodex mite is diagnosed in half of adult patients seeking ophthalmic care. Pathomorphological descriptions of specific patterns associated with the presence of Demodex infection are practically absent. During pathological examination, in the vast majority of cases it is almost impossible to see the parasite in the test material. There are pathomorphological patterns associated with the presence of the mite as a commensal, not only on the eyelid surface or in the conjunctiva, but also in morphological structures formed against the background of pathological processes in this area. Aim. To find out the morphological patterns reflecting the pathomorphosis of some tumor processes in the eyelid thickness caused by demodectic invasion, which have not been identified so far in ophthalmopathological studies. Materials and Methods. We analyzed the archival material from the oculo-conjunctival region submitted to the ocular pathology laboratory within the period of 2020–2023. Surgical and biopsy specimens were processed by standard histologic methods. Results. One of the pathognomonic patterns of demodecosis are calcifications with fragments of the dead mite and cysts. When a mite rapidly destroys tissue, it leaves the site until it dies without retaining its fragments. Post-demodecosis pathomorphosis in basal cell carcinoma of the eyelids complicates the pathomorphologic diagnosis of the biopsy. Conclusions. Our results prove the presence of mites in tumor tissues and illustrate their influence on the development of the pathomorphological picture, which should be taken into account in the practical activity of a pathologist. Keywords: demodex mite, pathomorphology, ophthalmopathological examination, oculo-conjunctival region.