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Introduction

Kimura’s disease has a benign clinical course with atriad of features: painless mass, eosinophilia, and raisedserum IgE (1, 2). In most of the previously reportedcases, Kimura’s disease typically presents as single ormultiple subcutaneous lesions in the head and neck,especially in the parotid and submandibular regions (3-6). There are some studies that have demonstratedimaging findings of Kimura’s disease in other lesscommon sites, such as thorax, abdomen and upperextremity (7-9), but to the our knowledge, there has noreport about the imaging findings of Kimura’s diseasein lower extremity without involvement of head andneck. Clinical findings of Kimura’s disease in an

unusual location are occasionally suggestive ofmalignant soft tissue sarcoma due to its growing natureand associated regional lymphadenopathy without anyinfectious sign. When considering characteristicimaging findings in the diagnostic algorithm,radiologists may play an important role in alerting theclinician to Kimura’s disease. Here, we report anunusual case of Kimura’s disease with respect to thelocation.

Case Report

A 37-year-old woman presented with a history of apainless palpable mass in the right medial thigh for amonth. There was no history of a precipitating traumaor of any increased or unusual activities. There was no

JKSMRM 12:55-59(2008)1Department of Diagnostic Radiology of Dankook University Hospital2Department of Diagnostic Radiology of Dongguk University Hospital3Department of Orthopedic Surgery of Konkuk University HospitalThis work was supported by the Dankook University Research Foundation. Received; February 12, 2008, revised; April 12, 2008, accepted; April 25, 2008Address reprint requests to : Jee Young Lee, M.D., Department of Diagnostic Radiology of Dankook University Hospital,

330-715, San 16-5, Anseo-Dong, Cheonan, Chung-Nam, Korea.Tel. 82-41-550-6921, Fax. 82-41-552-9674 E-mail: jyleee@dankook.ac.kr

Kimura’s Disease in the Lower Extremity: A CaseReport Mimicking the Malignant Soft Tissue Mass

Jee Young Lee, M.D.1, Kyung Jin Suh, M.D.2, Hong-Geun Jung, M.D.3

We present a case of a 37-year-old woman who had Kimura’s disease involving thelower extremity mimicking malignant soft tissue mass. The diagnosis of Kimura’sdisease would be considered if there is a subcutaneous solid mass showing thepreservation of the nodal architecture with perinodal infiltrations and the laboratoryexaminations for peripheral eosinophilia and serum IgE level should berecommended although it occurs at the lower extremity.

Index words : Kimura’s diseaseLower extremity Images

history of fever, night sweat, or weight loss. Onphysical examination, she appeared in good health. Anon-tender, deeply located mass measuring 5×3 cmwas palpable in the upper medial side of the rightthigh. There was no discoloration or heating sensationoverlying the skin. There were several lymph nodesmeasuring 1-2 cm in the right inguinal area. Theclinical diagnosis of a soft tissue tumor with regionallymph node metastasis was made and she wasexamined with MRI. MRI demonstrated a poorlydefined subcutaneous mass with eccentric fat andvascular signal void dots(Fig. 1. A-C) Peritumoral softtissue infiltrations and diffuse enhancement of themass were noted (Fig. 1. C). Several reactive lymphnodes were located in the right inguinal region justabove the mass (Not shown here). The eccentricallylocated fat signal and signal void dots suggestedpathology of a lymph node preserving nodalarchtecture or fatty mass with an unusualmanifestation such as lipoma variants rather thananother neoplastic process of soft tissue.

The US showed this mass as a large lymph node withpreservation of nodal architecture and perinodalinfiltrations, rather than soft tissue sarcoma or any

other solid mass type (Fig. 1D). Several reactive lymphnodes in the inguinal area with the same architecturewere also noted (Not shown here). As a diagnosticconsideration, lymphoproliferative disorder would behighly indicative. Laboratory data revealed a whiteblood cell count of 11.84×103 /mm3 ; differential countshowed 41% eosinophils (normal range of 1-6%) andextremely high serum immunoglobulin E (IgE) level;68,300 IU/ml out of the normal range of 0-87.0 IU/ml.The associated peripheral eosinophilia and increasedserum IgE levels made this lesion strongly suggestivefor Kimura’s disease. The patient underwent simpleexcision of the enlarged lymph nodes.

The pathological diagnosis confirmed Kimura’sdisease. The microscopic findings demonstrated a largelymph node with infiltrated mantle zone and perinodalfatty tissue by the numerous eosinophils (Fig. 1E-G).Several small lymph nodes from the right inguinalnodal station showed a similar manner of eosinophilicinfiltrations (Not shown here).

Discussion

Kimura’s disease is a chronic inflammatory disorder

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a b cFig. 1. a-c. Axial MR images of the right thigh. T1- weighted spin-echo image (a) and fat suppressed T2-weightedfast spin-echo image (b) show a irregular marginated solid mass in the subcutaneous fatty layer of the right upperthigh. The mass is iso- to slightly hyperintense relative to muscle on T1- weighted spin-echo image and hyperintenserelative to muscle on T2-weighted fast spin-echo images. Gadolinium-enhanced T1- weighted spin-echo image withfat saturation (c) show a diffuse homogeneous enhancement. Note the eccentric fatty tissue umbilicating theanteromedial aspect of the mass on the T1- weighted spin-echo image and the signal voids along this on all imagesequences (arrows). This characteristic imaging findings would suggest the pathology of lymph node rather thansarcomatous lesions or other soft tissue tumors.

of unknown origin and benign clinical course. Kimura’sdisease appear to be endemic in the Asian populationand can occur at any age but commonly have occurredduring the second and third decades of life. Men aremore commonly affected than women, and the male-to-female ratio is greater than 3:1. The onset is insidiousand the manifestations include enlarged nodular massesin the deep subcutaneous tissue of the head and neckregion, most frequently intraauricular or retroauricular

(1, 2). Kimura’s disease in almost all cases involves theregional lymph nodes and histologically, has threecomponents: cellular (inflammatory infiltrate includingincreased eosinophils and follicular hyperplasia),fibrocollagenous, and vascular (arborizing vascularproliferation of the postcapillary venule, althoughendothelial cells are usually flat and lack cytologicatypia or vacuolization) (4). Painless slow growingpalpable mass may mimic a malignant soft tissue mass

Kimura’s Disease in the Lower Extremity

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d e

f gFig. 1. d. Ultrasonography showed an enlarged lymph node with a preservation of the central echogenic fatty hilum,thickened cortex and perinodal infiltrations.e--g. Photomicrographs of specimen. Prominent eosinophilic infiltrates with hyperplastic follicles that were highlyvascularized in a lymph node (e, hematoxylin-eosin, ×400). Dense lymphoid and eosinophilic infiltrations in theperinodal soft tissue (SC) crossing the capsule (C) of the lymph node (f, hematoxylin-eosin, ×200). Central fattyhilum with large hilar vessel (arrow) were identified (g, hematoxylin-eosin, ×12). Gross contour of nodalarchitecture of the largest enlarged lymph node was preserved on gross pathology mapping (Not shown here).

C

SC

in a case of unusual location of Kimura’s disease. Manyimaging findings of head and neck involvement havebeen documented (3-6). Severeal case reports ofunusual location, such as thorax, abdomen and upperextremity described CT or MR findings of Kimura’sdisease (7-9). The imaging findings of Kimura’s diseasein thorax and abdomen with CT showed extensiveaggregated lymphadenopathy and in the upperextremity with MRI showed uniform internal signalintensity with iso- to slightly higher than that of skeletalmuscle on T1-weighted images and high signalintensity on T2-weighted images, homogeneousenhancement, signal-void structures within the massand surrounding edema. Despite the unusual locationin our case, we discovered similar MRI imagingfindings to Kimura’s disease in the upper extremity.We concerned the fat signal intensity umbilicating thismass on T1-weighted images and signal void dotstraversing this fatty portion. The US showed this areaas an echogenic fatty hilum of an enlarged lymph nodewith preservation of nodal architecture. Pathologicreview according to specimen mapping revealed nodalhilum containing large afferent vessels in an enlargedlymph nodes. Therefore, signal void structure in thecentral area of the mass represents vascular structureof the nodal hilum. In our opinion, the fat signalintensity and signal void structure umbilicating themass on T1-weighted images of MRI was very crucialin characterizing this lesion as a pathology in the lymphnode. It may be an important MR finding in cases ofsoft tissue mass to differentiate the lymphatic pathologyfrom sarcomatous lesion. Although a subcutaneoussolid mass may have malignant looking appearance onthe MRI, it should be carefully interpreted for eccentricfatty tissue containg the arteries on the MRI. Inaddition, US also has an important role incharacterization of this subcutaneous mass. In additionto soft tissue sarcoma other differential diagnoses forKimura’s disease in the lower extremity should includelymphoma, metastatic lymphadenopahty, infectiouslymphadenopathy, such as tuberculous lymphadenitis

and pyogenic lymphadenitis, Calstleman’s disease anddrug-induced lymphadenopathy. First, soft tissuesacorcoma should be ruled out and then pathology inlymph nodes could be differentiated consideringlaboratory findings and biopsy.

In conclusion, Kimura’s disease in the lowerextremity is a very rare benign disorder which could beconfused with a malignant soft tissue mass. Concerningthe characteristic US and MRI findings withpreservation of the nodal architecture and perinodalinfilatrations in cases of a subcutaneous solid mass, apreoperative diagnosis of Kimura’s disease could bepossible in the presence of peripheral eosinophilia andincreased serum IgE levels.

References

1.Kimura T, Yoshimura S, Ishikaura E. Unusual granulationcombined with hyperplastic changes of lymphatic tissue.Trans Soc Pathol Jpn 1948;37:179-180.

2.Kim BH, Sithian N, Cucolo GF. Subcutaneous angiolymphoidhyperplasia (Kimura disease). Report of a case. Arch Surg1975;110:1246-1248.

3.Hiwatashi A, Hasuo K, Shiina T, et al. Kimura’s disease withbilateral auricular masses. AJNR Am J Neuroradiol 1999;20:1976-1978.

4.Kung IT, Gibson JB, Bannatyne PN. Kimura’s disease: aclinicopathological study of 21 cases and its distinction fromangiolymphoid hyperplasia with eosinophilia. Pathology 1984;16:39-44.

5.Ahuja AT, Loke TK, Mok CO, Chow LT, Metreweli C.Ultrasound of Kimura’s disease. Clin Radiol 1995; 50:70 -173.

6.Ching ASC, Tsang WM, Ahuja AT, Metreweli C. Extranodalmanifestation of Kimura’s disease: ultrasound features. EurRadiol 2002;12:600-604.

7.Lee IJ, Park SY, Ha HK, Kim PN, Lee MG, Auh YH.Kimura’s disease: CT features of abd! ominal involvement ina case. J Korean Radiol Soc 1999;41:125-127.

8.Lee IJ, Choe HS, Min SK, Ko EY, Lee JY, Kim HB, Lee KS, etal. CT findings of Kimura’s disease involving thorax: ! Casereport. J Korean Radiol Soc 2003;48:413-416.

9.Choi JA, Lee GK, Kong KY, Hong SH, Suh JS, Ahn JM, LeeYJ, Cho KH, Park JG, Choi JY and Kang HS. ImagingFindings of Kimura’s Disease in the Soft Tissue of the UpperExtremity. AJR Am J Roentgenol 2005;184:193-199.

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Kimura’s Disease in the Lower Extremity

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통신저자 : 이지영, (330-715) 충남 천안시 안서동 산 16-5, 단국대학교 영상의학과Tel. (041) 550-6921 Fax. (041) 552-9674 E-mail: jyleee@dankook.ac.kr

하지에 생긴 Kimura 병: 연부 조직 악성 종괴 형태로 발생한 증례 보고

1단국대학교 영상의학과2동국대학교 영상의학과

3건국대학교 정형외과

이지영1·서경진2·정홍근3

37세 여자 환자의 하지에 연부 조직 악성 종양 형태로 발생한 Kimura 병을 보고 하고자 한다. 하지에 발생하는 경

우는 매우 드물지만 피하 지방층에 경계가 안 좋은 고형 종괴가 임파선 형태를 유지하며 주위 조직으로 침윤이 있다면

Kimura 병을 감별진단에 포함시켜야 하며 말초 혈액검사와 혈청 IgE 수치 측정을 권유하여야 할 것으로 생각된다.

대한자기공명의과학회지 12:55-59(2008)