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Kimura disease

Kimura disease presents with subcutaneous masses and lymph node enlargement in the head and neck, particularly cervical nodes near the mandibular angle and postauricular regions, typically in young males (20-40 years) from Asia. Imaging is performed to characterize the extent of nodal and salivary gland involvement and guide management decisions.

Key Images

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Look For First
  • Marked enlargement of cervical lymph nodes with predilection for parotid region and epitrochlear nodes, rather than posterior triangle
  • Homogeneous hyperenhancing nodes on T2 and post-contrast imaging with flow voids indicating high vascularity
  • Associated enlargement of parotid and submandibular salivary glands with heterogeneous signal
  • Hilar vascularity on ultrasound (90% of cases) and diffuse homogeneous enhancement on post-contrast MRI
Key Image Findings
  • On ultrasound: solid, enlarged hypoechoic nodes (90%) usually maintaining hilar architecture with increased hilar vascularity (90%); necrosis is uncommon (15%)
  • On CT: marked cervical node enlargement with intense homogeneous enhancement and heterogeneous enhancement of major salivary glands
  • On MRI T1: lymph nodes and affected tissues appear hypointense or isointense compared with salivary gland tissue
  • On MRI T2: nodes typically hyperintense compared to salivary gland tissue with variable signal depending on degree of fibrosis present
  • On MRI post-contrast: usually homogeneous enhancement of lymph nodes with prominent flow voids within masses due to high vascular proliferation
  • Salivary glands appear hypoechoic on ultrasound but usually more heterogeneous than the lymph nodes; may show heterogeneous enhancement on CT and variable T2 signal on MRI
  • The disease spares the posterior triangle of the neck, distinguishing it from Kikuchi-Fujimoto disease which has posterior triangle predilection
  • Histologically characterized by lymphoid follicle proliferation, eosinophilic infiltrates (sometimes forming eosinophilic abscesses), vascular proliferation of post-capillary venules, and fibrosis
Differential Diagnosis
  • Kikuchi-Fujimoto disease: presents with lymphadenopathy in posterior triangle, whereas Kimura disease has parotid region and epitrochlear node predilection
  • Reactive lymph nodes or infectious mononucleosis: benign nodes typically smaller, may show some enhancement but less homogeneous and intense than Kimura disease
  • Lymphoma/leukemia: can mimic with nodal enlargement and enhancement, but typically shows more heterogeneous signal and different clinical context; biopsy showing eosinophilic infiltrates distinguishes Kimura disease
  • Angiolymphoid hyperplasia with eosinophilia (ALHE): affects primarily white females, involves dermis without lymph node enlargement, clinically and radiologically distinct from Kimura disease
  • Castleman disease: can present with nodal enlargement and enhancement but typically hyaline vascular type shows different enhancement pattern; lacks associated peripheral eosinophilia
  • Tuberculous adenitis: typically shows rim enhancement and central necrosis; peripheral eosinophilia and marked serum IgE elevation favor Kimura disease
Discussion

Kimura disease is a rare benign inflammatory disorder of unknown etiology presumed related to an immunological response to an unidentified infectious agent

Male predominance (80%) and typical presentation in 20-40 year olds with geographic predominance in Asia are key clinical clues

Characteristic elevation of serum immunoglobulin E (IgE) levels and peripheral eosinophilia in blood and tissues help distinguish Kimura disease from other nodal pathologies

High vascularity reflected by prominent hilar vascularity on ultrasound (90%) and flow voids on MRI corresponds to vascular proliferation of post-capillary venules seen on histology

Treatment options are varied (conservative management, radiotherapy, steroids, cyclosporine, resection) due to lack of established protocols, with high recurrence rates for steroids and surgery favoring radiotherapy in some cases

Young age at presentation necessitates careful consideration of treatment approach, as recurrence and morbidity from aggressive therapy must be balanced against the benign nature of the disease

Reporting Pearls

Report Kimura disease by specifically noting the parotid region and epitrochlear node predilection (not posterior triangle), describe the nodes as markedly enlarged, homogeneously hypoechoic or hyperintense on T2, with intense homogeneous enhancement and prominent hilar vascularity, and correlate with clinical context of young Asian males with peripheral eosinophilia and elevated IgE levels.

Pitfalls
  • Confusing Kimura disease with Kikuchi-Fujimoto disease: the two conditions have distinctly different nodal distributions (parotid/epitrochlear in Kimura vs. posterior triangle in Kikuchi-Fujimoto)
  • Mistaking Kimura disease for lymphoma or metastatic nodes: the homogeneous enhancement and lack of central necrosis, combined with hilar vascularity and preserved nodal architecture, are more consistent with Kimura disease
  • Overlooking the high vascular proliferation component: prominent flow voids and hilar vascularity on imaging reflect the underlying pathology and help distinguish Kimura disease from reactive nodes
  • Not correlating imaging with laboratory findings: the combination of peripheral eosinophilia and markedly elevated serum IgE is key to narrowing the differential diagnosis toward Kimura disease
Source: Reference source

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