Conjunctival lymphomas are predominantly extranodal B-cell non-Hodgkin’s lymphomas (NHL), most of them are MALT-lymphomas originating from the mucosa-associated lymphoid tissue. Manifestations of the conjunctival NHL are very diverse, and often imitate the appearance of other ocular diseases, which makes their clinical diagnosis difficult and significantly lengthens the time from the first visit to the ophthalmologist until the diagnosis is verified. The article presents the case histories of two young patients who were treated for a long time at the place of residence as acute chlamydial conjunctivitis (in one case — 3, in the other — almost 5 months). A comprehensive laboratory study to detect specific blood antibodies, DNA of the pathogen in conjunctival scrapings and the cytological picture of the conjunctiva did not confirm the chlamydial etiology of the process. A pronounced lymphoid reaction mainly due to small lymphoid cells was found in both patients in scrapings from the conjunctiva of the eyelid, which was the basis for referring patients for consultation to oncologist. Histological examination of conjunctival biopsy specimens also revealed proliferation of lymphoid tissue: patients with suspected MALT lymphoma were referred to onco-hematologists. A PCR analysis of the biopsy material revealed HHV-8 DNA in one patient and Epstein-Barr (EBV) DNA in another, although no pathogen genomes were detected in the conjunctiva scrapings. Immunohistochemical analysis in one patient confirmed the conjunctival MALT-lymphoma, in another one diagnosed hyperplasia of the conjunctival mucous-associated lymphoid tissue, caused by prolonged antigenic stimulation (EBV DNA was detected in the biopsy). The follicular appearance of the lymphocyte hyperplasia in conjunctiva may imitate the clinical picture of infectious diseases. For differential diagnosis of chlamydial conjunctivitis and MALTlymphoma, especially in young patients with refractory follicular conjunctivitis, it is advisable to include a set of serological, molecular biology and cytological methods.
Colonic mucosa-associated lymphoid tissue (MALT) lymphoma: an important differential diagnosis for a slow-growing colonic polyp