Sudden onset unilateral renomegaly as an initial manifestation of primary Sjögren's syndrome in a teenage girl.

An 18-year old girl suddenly developed left-sided abdominal pain with otherwise normal clinical and urine examination. Ultrasound and computed tomography demonstrated a left renomegaly with uniformly normal structure without hydronephrosis, abnormal renal venous flow or ruptured extrauterine pregnancy. Renal biopsy showed lymphocytic interstitial nephritis, compatible with exocrine gland focus score abnormalities, consistent with those found in patients with Sjögren's syndrome. The renomegaly started to diminish after 10 days and the kidney reached normal size after 2 months. All objective tests for keratoconjunctivitis sicca and xerostomia were abnormal, although daily persistent dry eyes and dry mouth symptoms were absent. Serological tests showed high levels of anti-nuclear antibodies, anti-SS-A and anti-SS-B antibodies. Thus the patient fulfils the classification criteria for primary Sjögren's syndrome. The suddenly developed unilateral renomegaly may be an early clinical manifestation of this disease.