Case of the Week
Section Editors: Matylda Machnowska1 and Anvita Pauranik2
1University of Toronto, Toronto, Ontario, Canada
2BC Children's Hospital, University of British Columbia, Vancouver, British Columbia, Canada
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July 25, 2019
Kimura’s Disease
- Background
- Kimura’s Disease, or KD, is a benign, rare, chronic inflammatory condition with several proposed etiologies including an aberrant immune reaction, immunoglobulin E-mediated hypersensitivity reaction, trauma, or chronic infection.
- It is often called eosinophilic granuloma of the soft tissue.
- Endemic in Japan and Southeast Asia, KD has a peak incidence in the second and third decades of life.
- Clinical Presentation
- Classically presents in young Asian men with a painless, slow-growing, subcutaneous nodule usually manifesting on the face or neck with the parotid region being the most common site of involvement.
- Orbital involvement is rare, but when occurs usually affects the lacrimal glands or eyelids. Regional or satellite lymphadenopathy may be present. Complications of the disease include asthma, urticaria, and nephritis, but constitutional symptoms are usually absent.
- Key Diagnostic Features
- The final diagnosis relies on typical histopathology findings of the mass or lymph node which reveal prominent proliferation of lymphoid follicles with germinal centers displaying inter-follicular infiltration by eosinophils, as well as variable degrees of fibrosis and vascular proliferation.
- CT imaging findings usually reveal single or multiple mild-to-moderately enhancing masses between 1-8 centimeters in diameter. Unilateral swelling of a rectus muscle may be the first sign of Kimura’s disease of the orbit prior to the development of proptosis, while lymphadenopathy may be the first presenting sign in systemic disease.
- Differential Diagnosis
- Idiopathic Orbital Inflammation (IOI), also known as Orbital Pseudotumor, may present very similar to KD with a chronic course, unilateral ocular muscle swelling, and optic nerve atrophy; however, in about 75% of cases, CT imaging reveals either a focal mass within the orbit involving the tendinous insertion or a lacrimal pseudotumor with concurrent blepharitis, acute pain, and conjunctival congestion.
- Lymphoproliferative Disease, including Orbital Lymphoma and Reactive Lymphoid Hyperplasia, is also usually painless and unilateral but commonly affects the extraconal compartment and rarely the extraocular muscles. CT imaging reveals homogenous, mildly-enhancing, lobulated masses that mold around surrounding structures.
- Orbital Metastases, usually breast, bronchogenic, prostate, and renal cell carcinoma, present with pain and diplopia rather than painless proptosis and vision loss. Imaging reveals well-defined or diffusely infiltrative lesions that most commonly involve the extraconal compartment.
- Angiolymphoid hyperplasia with eosinophilia (ALHE) was once synonymous with Kimura’s Disease as it presents with similar clinical and histopathological features. However, it is most common in middle-aged women with absent lymphadenopathy. ALHE has a less chronic course and is now differentiated by a predominantly vascular process with abundant vascular proliferation and cytoplasmic vacuoles. It is also less likely to involve the orbit and when it occurs usually involves the adnexal structures.
- Eosinophilic granulomatosis with polyangiitis may present similarly though there is pulmonary involvement in almost all cases. CT imaging of the orbits reveal diffuse inflammatory infiltrate that molds to the orbital contour and may involve the extraocular muscles. Contiguous extension from the paranasal sinuses and bony erosion may be present.
- Sarcoidosis of the orbit is usually bilateral and anterior uveitis is the most common manifestation.
- Kaposi’s sarcoma of the orbit will reveal intense contrast enhancement though systemic disease, including cutaneous lesions and lymphadenopathy, will be present
- Treatment
- Due to its rarity, no standard treatment has been established; however, efficacy has been reported in small case series and individual case reports in which the preferred treatment for localized disease is surgery. Surgical excision with postoperative radiation has shown the smallest risk of recurrence; however, local radiation therapy alone, systemic corticosteroid and immunosuppressant therapy, leukotriene receptor antagonists, and histamine receptor blockers have all shown success.
- No case of malignant transformation has been reported, though there is an isolated report of spontaneous resolution. Although the disease has a chronic, relapsing course and a high rate of recurrence following any type of treatment, the overall prognosis is favorable.
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