Kimura’s disease presenting with intraparotid and neck nodes: A case report and review of literature

Abstract

Kimura’s disease (KD) is a rare chronic inflammatory disorder of unknown etiology. The purpose of this article is to increase the awareness of clinicians regarding KD presenting with intraparotid and neck nodes which can mimic various inflammatory and neoplastic conditions. A 22-year-old man presented with a slow-growing left parotid swelling for 3 years. Ultrasound and computed tomography showed multiple enlarged intraparotid and neck nodes. Fine needle aspiration results showed lymphoid tissue hyperplasia. A diagnosis of KD was based on characteristic histopathological findings after a superficial parotidectomy in conjunction with peripheral eosinophilia. KD should be included in the differential diagnosis especially in young Asian men with slow-growing lesions and peripheral eosinophilia. Cytology by fine needle aspiration is useful to exclude malignancy but the results may be inconclusive. Surgical excision is best for definitive histopathological diagnosis, and has been the mainstay of treatment of KD.

Introduction

Kimura’s disease (KD) is a rare chronic inflammatory angiolymphatic proliferative disorder of unknown etiology. ¹ Most cases have been reported in young Asian men presenting with painless masses involving subcutaneous tissue, lymph nodes, or salivary glands primarily in the head and neck region, accompanying with blood eosinophilia and elevated serum immunoglobulin E. ¹ The lesions can mimic a malignant tumor or chronic infection.

Parotid gland involvement has been variably reported in 10–58% of KD cases.^1,2 Parotid gland swelling in KD results from lesions in the intraparotid lymph nodes or adjacent subcutaneous connective tissues, without involvement of the parotid parenchyma. ¹ There have been only 5 reported cases of KD presenting with intraparotid lymph nodes enlargement.^3-7 Herein, we report the case of a young man with left parotid swelling from intraparotid node enlargement and regional lymphadenopathy. Unlike previous reports, the diagnosis of KD in this case was difficult in the absence of typical cytological characteristics. A definite diagnosis was established based on histological findings after surgical excision. A review of the literature is provided, and the differential diagnosis is discussed.

Case report

A 22-year-old Thai man presented with left parotid gland swelling which had been slowly increasing for 3 years. There was no history of pain, fever, night sweats, or weight loss. The physical examination showed a non-tender, firm mass measuring 2 × 2 × 4 cm extending from the left angle of the mandible to the postauricular area with normal overlying skin. There was also a palpable node sized 1.5 cm at the leveI II left neck. There was no facial palsy. Fine needle aspiration (FNA) results showed lymphoid tissue hyperplasia of the intraparotid lymph node, without atypical cells. FNA findings of the left neck node also showed reactive lymphoid hyperplasia. The ultrasonographic and computed tomography (CT) findings are shown in Figure 1. Laboratory data included hemoglobin of 16.7 g/dL, platelet count of 293,000/uL, and white cell count of 10,300/uL: differentiation showed 30.9% eosinophils, 37.9% neutrophils, 25.4% lymphocytes, and 4.7% monocytes. Blood urea nitrogen, creatinine, electrolytes, and urinary analysis were normal. A chest radiograph was unremarkable.

Figure 1.

(A) Gray-scale color doppler ultrasound image showing a group of enlarged hypoechoic nodes with hilar vascularity at the left intraparotid and periparotid areas. (B) Axial contrast-enhanced CT showing multiple homogeneously enhancing left cervical nodes involving the left parotid and periparotid regions. (C) The coronal image shows associated cervical lymphadenopathy, greater on the left than the right.

A benign tumor or inflammatory lesion was suspected. Malignant lesions, for example, lymphoma or nodal metastases, although unlikely from the clinical presentation, could not be totally excluded. A lymph node biopsy was suggested, but the patient decided to go directly to surgery due to cosmetic concerns at the parotid area. A left superficial parotidectomy was performed. During the operation, the plane between the subcutaneous tissue and the parotid gland was well-defined. The main trunk of the facial nerve and its branches were identified. The superficial lobe of the parotid gland was dissected and removed. The deep lobe of the parotid gland was not involved. Macroscopically, several gray-white irregular rubbery nodules measuring 0.5–2.0 cm were seen within the parotid gland. A microscopic examination revealed numerous nodal and extranodal reactive lymphoid follicles with germinal centers, dense eosinophil infiltration, eosinophilic microabscesses, stromal fibrosis, and increased vascularity (Figure 2). A diagnosis of KD was then made based on the histopathogical findings in conjunction with the clinical presentation and marked peripheral eosinophilia. The postoperative period was uneventful. At the 6-month follow-up, there was no recurrence.

Figure 2.

Histological findings showing reactive lymphoid follicles with germinal centers, and prominent eosinophilic infiltration with microabscess formation (H&E stain, 40X).

Discussion

The slow-growing nature of the lesion in this patient favors benign tumor or chronic inflammation of the parotid gland. However, malignancy or chronic infection could not be excluded, especially in the presence of cervical lymphadenopathy. The reported cases of KD with intraparotid nodes including the present case are summarized in Table 1. Among the other 5 published cases, 3 had accompanying cervical lymphadenopathy, and 4 had cytological results of lymphoid cells mixed with the predominance of eosinophils which were compatible with KD. In our case, the FNA results showing lymphoid tissue hyperplasia without atypical cells was considered inconclusive so tissue pathology was required.

Table 1.

Case reports of Kimura’s disease presenting with intraparotid nodes enlargement.

Report	Age	Sex	Clinical presentation	Cytology	Ultrasound findings	CT/MRI findings	Management
Present case	22	M	Left parotid swelling 2 × 2 × 4 cm with bilateral neck nodes for 3 years	Lymphoid tissue hyperplasia of the intraparotid lymph node, without atypical cells	Enlarged hypoechoic nodes with well-defined border and hilar vascularity at the left intraparotid and periparotid areas	CT - multiple homogenous enhancing intraparotid and periparotid nodes at the left superficial gland, with homogenous enhancing bilateral neck nodes	Superficial parotidectomy
Shivakumar et al. 6	21	M	Right parotid mass 6 × 7 cm with multiple right neck nodes for 2 years	Reactive lymphoid cells, mast cells, tingible body macrophages, numerous eosinophils, and a few Warthin-Finkeldey-like giant cells, without atypical cells	Multiple enlarged right intraparotid and right neck nodes	CT - enlarged enhancing parotid gland with subcutaneous fat stranding. Enlarged enhancing right neck nodes	Steroids
Ong et al. 7	43	M	Bilateral parotid swelling (right 10 × 15 cm and left 5 × 6 cm) for 5 months	Polymorphous population of lymphoid cells with predominance of eosinophils	––	CT - heterogenous enlargement of bilateral parotid glands, with multiple nodules of varying sizes. Extensive fat streakiness of overlying subcutaneous plane with skin involvement. Multiple enlarged enhancing bilateral level I-V neck nodes	Steroids
Bonfils et al. 5	31	M	Left parotid swelling 4 cm	––	––	MRI - heterogenous and intermediate on T2-weighted images of the left parotid gland, small level Ib, and V left neck nodes with homogenous signal	Superficial parotidectomy
Boccato et al. 4	16	M	Right parotid gland swelling	Polymorphous lymphoid component, mature eosinophils, and eosinophilic granules in the background, without atypical cells	2 superficial round intraglandular structures, measuring 1 × 1.5 cm and 1.5 × 2 cm	––	Superficial parotidectomy
Chow et al. 3	36	M	Left parotid swelling 2.5 × 5 cm for 2 months	Small lymphocytes mixed with moderate number of eosinophils. Warthin-Finkeldey polykaryocytes	––	––	Excision

Note: CT = computed tomography; MRI = magnetic resonance imaging.

Imaging could be a useful adjunct investigation though a histological confirmation is necessary. The ultrasound and CT findings in our case, that the affected structures were enlarged intraparotid nodes and not salivary gland parenchyma, helped with the diagnosis. The differential diagnosis of intraparotid and neck node enlargement with FNA results of lymphoid tissue hyperplasia include Warthin’s tumor, lymphoma, granulomatous inflammation (e.g., tuberculosis), and chronic inflammation (e.g., KD or Castleman disease). The typical characteristics of these diseases are shown in Table 2. FNA of salivary glands is an excellent tool to distinguish neoplastic from non-neoplastic lesions. The accuracy of a salivary gland FNA in diagnosing malignant lesions is high, with a sensitivity of 70% and specificity of 99%. ⁸ The major limitations of FNA include some false negative results, and the possibility of an inadequate tissue sample. The diagnosis is usually straightforward in the presence of the typical cytomorphological findings, but the scarcity of characteristic features often leads to a diagnostic dilemma. In most KD cases, the interpretation of the cytology is inconclusive, and tissue biopsy or excision offers the best clues for definite diagnosis. ⁹

Table 2.

Differential diagnosis for intraparotid lymph node enlargement with fine needle aspiration results showing lymphoid tissue hyperplasia.

Disease	Clinical characteristics	Cytology	Histology	Imaging
Kimura’s disease	20–30-year-old Asian male	Polymorphous lymphoid cells with significant numbers of eosinophils, fragments of collagenous tissue, endothelial cells and, occasional Warthin-Finkeldey polykaryocytes	Prominent lymphoid hyperplasia with reactive germinal centers, eosinophil infiltration, eosinophilic microabscesses, and variable degrees of tissue fibrosis and vascular proliferation	CT - homogenous enhancement, ill-defined borders with extension into the subcutaneous tissue, no necrosis, no calcification MRI - iso- to slightly hyper-intense on T1-weighted images and hyperintense on T2-weighted images
Warthin’s tumor	50–60-year-old male Heavy smoking Multiple lesion (20%) and bilateral lesions (10%)	Lymphoid cells, oncocytic cells, and granular debris in background	Cystic and papillary epithelial components with a well-organized double layer of lymphoid stroma and oncocytic cells	CT - contrast enhancement, well-defined borders with cystic components and solid stroma
Lymphoma (especially non-Hodgkin lymphoma)	Children and young adults, B symptoms, lymphadenopathy, anemia Autoimmune disorder such as Sjögren syndrome, is associated with an increased risk.	Atypical lymphocytes, for example, small, intermediate, and large cells. Flow cytometry is usually required to confirm the diagnosis	Monomorphous small to medium-sized lymphocytes with irregular nuclei. Lack of hyperplastic germinal centers. Positive for immunohistochemical stains	CT - bilateral parotid involvement, multiple masses, lymphadenopathy, with ill-defined border
Tuberculosis	Young Multiple lesions (56%) Positive purified protein derivative skin test	Epithelioid granulomas with caseous necrosis	Granulomatous inflammation with caseous necrosis. Tubercles formed by epithelioid macrophages, langhans giant cells, and lymphocytes.	CT - rim enhancement, central necrosis, and occasional calcification MRI - isointense on T1, hyperintense on T2-weighted image, changes of parotid fascia and parotid parenchymal edema
Castleman disease	30–40-year-old Often occurs in chest, neck, and abdomen Unicentric, Multicentric	Lymphocytes, plasma cells, dendritic cells, eosinophils, and hyalinized capillary fragments	There are 2 major pathologic variations: (1) hyaline-vascular variant, the most frequent, characterized by small hyaline-vascular follicles and capillary proliferation; and (2) the plasma-cell variant, in which large lymphoid follicles are separated by sheets of plasma cells.	CT/MRI: well-defined homogenous enhancing nodes, central necrosis, and occasional calcification

Note: CT = computed tomography; MRI = magnetic resonance imaging.

Conservative treatment with steroids or cyclosporine is an initial option to avoid surgical risks. Surgery is an effective single treatment especially for patients with tumors smaller than 3 cm, and symptom duration shorter than 5 years. ¹⁰ However, recurrence rate is as high as 26%, 35%, and 50% after surgery, medication and radiotherapy, respectively. ¹⁰ Good practice is based on discussing the advantages and disadvantages of each modality with the patient.

Conclusion

Kimura’s disease is a rare chronic inflammatory disorder of unknown etiology that involves the subcutaneous tissue, lymph nodes, or salivary glands of the head and neck region. The presentation of our case highlights the need for awareness of Kimura’s disease by clinicians and pathologists. A high degree of suspicion leading to early diagnosis is helpful to put the clinicians in a better position for diagnosis and management. Cytology by fine needle aspiration is useful to exclude malignancy but the results may be inconclusive. Surgical excision is best for definitive histopathological diagnosis, and has been the mainstay of treatment of Kimura’s disease.