P115 Extranodal marginal zone lymphoma secondary to sjogren syndrome, an extremely rare association in children

Background and aimMarginal zone lymphomas represent 3% of all lymphomas and are divided into extranodal (ENMZL), splenic and nodal. ENMZL is characterised by indolent natural history, is usually diagnosed in localised stages (70%) and chronic antigen stimulation seems to be involved in its pathogenesis. Typically seen in the 6thdecade of life, it is responsible for 8% of adult non-Hodgkin lymphoma. According to multicentre NHL-BFM studies, the incidence of ENMZL in children is 0.1%, most commonly found in the gastrointestinal tract (44%). The salivary gland is involved only in 5% of paediatric patients, being preceded in 1/3 cases by Sjogren syndrome (SS). Herein, we report a 15-year-old girl with advanced ENZML of salivary glands following SS, a very rare diagnosis in children.METHOD AND ResultsFemale patient, 13y, presented with enlarged jaw area, was evaluated by an oral-maxillofacial surgeon and cherubism was excluded. Laterocervical ultrasound, head and neck MRI: hypertrophic parotid glands with cystic images, small adenopathies. Based on parotid swelling, dry mouth and eyes, bilateral hypo-lacrimation on Schirmer’s test, positive anti-Ro, anti-La and anti-nuclear antibodies, she was diagnosed with primary SS. At age 15: progressive parotid swelling, no ‘B’ symptoms, leucopenia 3.38 × 10^9/l, anaemia 10.5 g/dl, sedimentation rate 33 mm/h, LDH 225UI (n<200 UI), B2-microglobulin 2.62 mg/L (n=0,9–2 mg/L), normal bone marrow biopsy. Right parotid biopsy, immunohistochemistry and molecular biology: lymphoid proliferation of small-sized monocytoid cells, with lympho-epithelial lesions and marginal zone pattern (incorporating residual reactive germinal centre), CD20+, CD3-, kappa/lambda 5/1, FR2-JH+ in heavy-chain IG. PET-CT scan showed active sites in left parotid gland, supra and subdiaphragmatic lymph nodes. The patient was diagnosed with B-cell ENMZL of parotid glands, stage III A. She received 6 cycles of R-CHOP regimen (rituximab, cyclophosphamide, vincristine, doxorubicin, prednisone), at 3 week interval, had negative PET-CT after 4 and 6 courses and she is in complete remission 6 months after the end of therapy.ConclutionENMZL of parotid glands following SS is rarely seen, especially in paediatric patients, thus the knowledge about this lymphoma type is limited. It is low-grade and responds well to R-CHOP chemotherapy, even in advanced stages. Nevertheless, regular follow-up is required, as relapses can occur during the course of the disease.