Case Report: Steroid‐Responsive Ureteric Pseudotumour Causing Hydronephrosis in Sjögren Disease

Sjögren disease (SD) is a chronic autoimmune disorder characterized by lymphocytic infiltration of exocrine glands, resulting in sicca symptoms and a wide spectrum of extra-glandular manifestations. Renal and urinary system involvement in SD is well recognized, most commonly in the form of tubulointerstitial nephritis [1] and, less frequently, interstitial cystitis [2]. Herein, we report an unusual case of urinary obstruction caused by a presumed inflammatory mass-like lesion involving the left ureter in a patient with SD. A 52-year-old woman was diagnosed with SD in June 2016 after a one-year history of hand and foot pain, fatigue, and ocular sicca symptoms. Laboratory evaluation at diagnosis revealed antinuclear antibody (ANA) positivity at a titre of 1:320, strong positivity for anti-SS-A and anti-SS-B antibodies, keratoconjunctivitis sicca on ophthalmological examination, and a focus score of +2 on labial salivary gland biopsy. Her medical history was otherwise unremarkable except for unipolar depression treated with paroxetine. Initial treatment consisted of hydroxychloroquine (HCQ), a 3-month course of low-dose corticosteroids, and artificial tear drops. She was subsequently maintained on HCQ alone and remained clinically stable, with no evidence of systemic involvement or lymphoid malignancy, until October 2024. In October 2024, she presented with a three-day history of left flank pain, groin discomfort, urinary frequency, and dysuria. Complete blood count and peripheral blood smear were normal, with no atypical cells detected. The erythrocyte sedimentation rate (ESR) was 39 mm/h, and C-reactive protein (CRP) was elevated at 24 mg/L. Blood urea nitrogen was 17.2 mg/dL, serum creatinine was 0.72 mg/dL (eGFR 96.8 mL/min/1.73 m2), and complement levels, serum IgG4 concentration, and protein electrophoresis were within normal limits. Urinalysis revealed leukocyte esterase 3+, nitrite 2+, hemoglobin 1+, and marked pyuria (279 white blood cells per high-power field). Urine culture grew Escherichia coli (extended-spectrum β-lactamase negative). Urinary ultrasonography demonstrated a soft-tissue echogenic lesion within the lumen of the dilated distal left ureter at the ureterovesical junction, without detectable vascularisation on Doppler imaging. In addition, millimetric hyperechogenic foci were observed at the bladder entry site, accompanied by contour lobulation and irregularity of the adjacent posterior bladder wall. Oral amoxicillin–clavulanate was initiated, and a urological consultation was obtained. Computed tomography (CT) urography revealed grade 0–I hydronephrosis and dilatation of the distal left ureter up to 7 mm, with intraluminal contrast at the ureterovesical junction. At this level, there was marked luminal narrowing due to an approximately 18 × 7 mm intraluminal soft-tissue density (Figure 1A,B). Additional suspicious soft-tissue densities and contour lobulation were noted along the posterior bladder wall. A double-J ureteral stent was placed, followed by diagnostic ureteroscopy with biopsies and cytological evaluation. Neoplasia was excluded, and histopathological examination revealed fibrous tissue with fibrin deposition and chronic inflammatory infiltrates. The patient was started on methylprednisolone 40 mg/day for 1 month, which was subsequently tapered on a weekly basis according to clinical response and follow-up CT urography findings. At the 3-month follow-up visit, the double-J stent was removed. Repeat CT urography demonstrated complete resolution of ureteral dilatation and hydronephrosis, with no residual soft tissue lesion (Figure 1C,D). Taken together, the histopathological findings and the complete radiological regression following corticosteroid therapy was considered consistent with, and suggestive of, an inflammatory pseudotumour potentially associated with SD. To our knowledge, only a single similar case has been reported in the literature [3]. Yuhara et al. described ureteric obstruction and hydronephrosis in a 67-year-old patient with SD, attributed to pseudolymphomatous infiltration [3]. Unlike that case, which was associated with systemic lymphadenopathy and histological features consistent with pseudolymphoma, our patient had a localized ureteric lesion without lymphoid hyperplasia or other systemic involvement. Beyond the ureter, pseudotumoural lesions associated with SD have been reported in other organs, including the central nervous system and pancreas [4-6]. These reports describe mass-like inflammatory lesions with favorable responses to corticosteroid therapy, similar to our case. The interpretation of the SD-associated inflammatory pseudotumour in this patient was based on histopathological findings demonstrating fibrotic tissue with chronic inflammatory infiltration, along with complete regression of the lesion and resolution of hydronephrosis following corticosteroid therapy. These features were considered consistent with an immune-mediated inflammatory process. A major limitation of this case is the lack of a comprehensive immunohistochemical analysis, which prevents the definitive exclusion of other important mimics that respond to steroids. Therefore, the diagnosis relies primarily on histological morphology, radiological development, and treatment response. Due to the lack of immunohistochemical confirmation, this case is presented as a clinically instructive report rather than a definitively diagnosed case. While response to corticosteroid therapy supports the diagnosis of inflammatory pseudotumour, it is not diagnostic in isolation. Nevertheless, clinical and laboratory findings argued against alternative diagnoses, including IgG4-related disease, low-grade lymphoma (MALT), Castleman disease, inflammatory myofibroblastic tumor (IMT), and sarcoidosis. Serum IgG4 levels were normal, and there were no clinical features suggestive of IgG4-related disease, such as retroperitoneal fibrosis, multiorgan involvement, or indolent progression [7]. The absence of B symptoms, lymphadenopathy, organomegaly, cytopenia, and hypocomplementemia reduced the likelihood of lymphoma [8]. Castleman disease was considered unlikely due to the absence of lymphadenopathy, systemic inflammation, characteristic laboratory abnormalities, and typical histopathological features [9]. Sarcoidosis was also deemed improbable, given the lack of non-caseating granulomas on histology, absence of pulmonary or mediastinal involvement, and normal supporting laboratory parameters [10]. IMT was considered less likely given the absence of reported spindle cell proliferation on histopathology, the lack of aggressive or progressive behavior, and the complete radiological resolution following corticosteroid therapy [11]. Nevertheless, in the absence of comprehensive immunohistochemical confirmation, alternative diagnoses cannot be entirely excluded, and this case should be interpreted as a probable SD-associated inflammatory pseudotumour. Although pseudotumoural lesions have been rarely reported in association with SD, to our knowledge, this is the first description of isolated ureteric involvement presenting as urinary obstruction. The diagnosis of an inflammatory pseudotumour was considered probable, supported by histomorphology and steroid response, although definitive exclusion of other entities would require immunohistochemical confirmation. This case underscores that inflammatory pseudotumour of the ureter, although exceptionally rare, may occur in SD patients without systemic disease activity and may closely mimic malignancy. Recognition of this entity is essential to avoid unnecessary surgical interventions, as timely diagnosis and corticosteroid treatment can lead to complete resolution. Reyhan Kose Cobanoglu: writing – original draft, writing – review and editing, conceptualization, data curation, investigation. Utku Sentosun: writing – review and editing. Erhan Ates: writing – review and editing. Gokhan Sargin: conceptualization, writing – review and editing. The authors have nothing to report. Written informed consent was obtained from the patient for publication of this case report and accompanying images. All identifying details have been removed to ensure anonymity. The authors declare no conflicts of interest. The authors have nothing to report.