Sjögren syndrome (SS) is a chronic autoimmune inflammatory disease targeting exocrine glands, causing sicca syndrome characterized by dry mouth (xerostomia) and dry eyes (keratoconjunctivitis sicca). Primary SS involves isolated gland involvement, while secondary SS occurs with other autoimmune diseases such as rheumatoid arthritis and systemic lupus erythematosus. Among salivary glands, the parotid is most commonly affected; bilateral, diffuse parotid enlargement is seen in 25-60% of patients. Submandibular and lacrimal glands may also be involved. Histologically, lymphocytic infiltration (CD4+ T cells) progressively destroys gland parenchyma, and acinar atrophy, ductal dilation, and intraglandular lymphoid nodules develop. The characteristic 'leopard skin' pattern on ultrasonography (multiple small hypoechoic areas widely distributed with intervening hyperechoic fibrous bands) is diagnostic and has been included in recent Sjögren diagnostic criteria. 'Pruned tree' or 'cherry blossom' pattern on MR sialography reflects ductular damage. Importantly, SS patients have a 16-44 fold increased risk of developing non-Hodgkin lymphoma (especially MALT lymphoma) compared to the general population (5-10%); regular follow-up is therefore mandatory.
Age Range
30-60
Peak Age
50
Gender
Female predominant
Prevalence
Uncommon
The pathophysiological basis of imaging findings in Sjögren syndrome is the progressive structural destruction caused by autoimmune lymphocytic infiltration in the gland parenchyma. CD4+ T lymphocytes and B lymphocytes infiltrate the gland parenchyma and focal lymphocytic sialadenitis develops (focus score ≥1 = ≥50 lymphocyte foci per 4 mm²). Lymphocytic infiltration destroys acinar cells — salivary production decreases (xerostomia). Fibrous tissue replaces acini and the gland parenchyma becomes heterogeneous. The 'leopard skin' pattern on ultrasonography reflects this mosaic appearance of intraglandular lymphoid nodules (hypoechoic) and surrounding fibrous/normal parenchyma (hyperechoic). In advanced stages, acinar atrophy increases, duct walls are damaged and dilate (pruned tree pattern on MR sialography). Ductular dilation and retention cysts may form. Chronic B cell stimulation prepares the ground for formation of germinal center-like structures and clonal B cell proliferation — this forms the molecular basis for MALT lymphoma development. On imaging, lymphoma transformation manifests as a new focal solid mass or component showing marked diffusion restriction within the existing heterogeneous pattern.
Widely distributed multiple small hypoechoic areas with intervening hyperechoic bands in the parotid gland on ultrasonography — pathognomonic US finding for Sjögren syndrome, included in diagnostic criteria.
Widely distributed multiple small (1-6 mm) hypoechoic areas and intervening hyperechoic fibrous bands in the parotid gland on US create the 'leopard skin' (or 'salt-and-pepper') pattern. This pattern reflects the mosaic of lymphocytic infiltration nodules (hypoechoic) and fibrous/normal parenchyma (hyperechoic). US grading system (0-4) assesses disease severity: Grade 0 = normal, Grade 1 = mild heterogeneity, Grade 2 = definite hypoechoic areas, Grade 3 = multiple hypoechoic nodules, Grade 4 = calcification/advanced atrophy. Sensitivity is 80-95%, specificity 90-98%, and it has been accepted as a non-invasive diagnostic criterion alternative to biopsy.
Report Sentence
Widely distributed multiple small hypoechoic areas with intervening hyperechoic bands ('leopard skin' pattern) are identified in both parotid glands; findings are consistent with Sjögren syndrome.
MRI shows heterogeneous signal in bilateral parotid glands. Multiple small T2 hyperintense foci (lymphoid nodules and dilated ductules) are distributed among hypointense fibrous stroma. In advanced stages, larger retention cysts may form. Gland size may be increased or decreased in advanced atrophy.
Report Sentence
Heterogeneous signal pattern with multiple small hyperintense foci on T2-weighted sequences is identified in both parotid glands; findings consistent with Sjögren syndrome.
On MR sialography (T1 post-contrast or STIR sequences) ductular damage appears as 'pruned tree' or 'cherry blossom' pattern. The main duct (Stensen's) may be preserved but terminal ductules are damaged — irregular dilations and fluid collections (sialectasis) appear as small bright foci.
Report Sentence
MR sialography demonstrates 'pruned tree' pattern consistent with terminal branch damage in bilateral parotid ductal system.
CT shows diffuse enlargement and heterogeneous density in bilateral parotid glands. Multiple small hypodense areas (lymphoid nodules/cysts) and soft tissue density areas create mosaic appearance. Heterogeneous enhancement on post-contrast series. In advanced stages, gland size may decrease (atrophy).
Report Sentence
Diffuse enlargement and heterogeneous density pattern is identified in both parotid glands; multiple small hypodense areas are present.
Color Doppler US may show diffusely increased vascularity in bilateral parotid glands — especially prominent during active inflammatory periods. Vascularity pattern is diffuse (not focal), supporting that hypervascularity is consistent with an inflammatory process.
Report Sentence
Diffusely increased vascularity is observed in bilateral parotid glands on Doppler examination; consistent with active inflammatory process.
Criteria
Isolated exocrine gland involvement, no other autoimmune disease
Distinct Features
Anti-SSA/Ro antibodies positive at high rate
Criteria
Accompanied by RA, SLE or other autoimmune disease
Distinct Features
Findings of underlying autoimmune disease accompany
Criteria
Development of MALT or DLBCL on existing SS background
Distinct Features
Focal solid mass + marked diffusion restriction + rapid growth
Distinguishing Feature
Well-defined cysts in HIV-BLEC, leopard skin pattern in Sjögren; differentiate with HIV test
Distinguishing Feature
Diffuse homogeneous enlargement in IgG4, heterogeneous pattern in Sjögren; differentiate with serum IgG4
Distinguishing Feature
Focal solid mass + marked diffusion restriction in lymphoma; diffuse heterogeneous pattern in Sjögren
Urgency
routineManagement
medicalBiopsy
Not NeededFollow-up
6-monthSymptomatic treatment (artificial tears, salivary stimulants) and immunomodulatory therapy is applied. Due to lymphoma transformation risk (5-10%), regular US follow-up every 6-12 months is mandatory. Biopsy is required in case of focal solid component or rapid growth.
Autoimmune treatment (immunosuppressives) is applied. Regular follow-up for lymphoma development is required (5-10% risk). Symptomatic treatment of dry eyes and mouth is important.