Asymptomatic Unilateral Inguinal Swelling with Peripheral Eosinophilia.

Clinical History and Examination

A 50-year-old male presented with right-sided inguinal swelling [Figure 1] for the past 1 year. Previously, the patient was clinically diagnosed as a case of tubercular lymphadenopathy and had received 6 months of antitubercular therapy without any noticeable improvement. Cutaneous examination revealed a single, mobile, firm, nontender, matted, irregular mass of size 6 × 6 cm in the right inguinal regional with normal overlying skin. Blood investigations showed peripheral eosinophilia (52%) with an absolute eosinophil count of 4500/mm3 and normal erythrocyte sedimentation rate. A regional fine needle aspiration cytology showed features of reactive lymphoid hyperplasia. The results of renal function tests, liver function tests, and routine urine tests were within normal limits, and chest radiography was unremarkable. Mantoux test was 5 × 5 mm.

Figure 1

Photograph shows right-sided inguinal swelling

Histopathology

A lesional biopsy revealed preserved architecture of lymphoid follicles with prominent germinal centers. Interfollicular areas showed prominence of eosinophils and plasma cells along with the presence of an occasional multinucleate giant cell [Figure 2]. Eosinophils were also seen infiltrating into lymphoid follicles and the capsule, with proliferation of capillaries and venules [Figure 3]. Stains and cultures were negative for bacteria, fungi, and mycobacteria.

Figure 2

Photomicrograph shows presence of sheets of eosinophils along with admixed plasma cells. Occasional multinucleated giant cell is also noted (H and E ×200).

Figure 3

Higher magnification shows a mixed population of eosinophils and plasma cells intermixed with mature lymphoid tissue (H and E ×400)

Answer

Kimura's Disease.

Discussion

Kimura's disease (KD) is a chronic inflammatory disease of unknown etiology. It presents as a single or multiple nontender subcutaneous nodules usually in the head and neck region. It has been mostly reported in the Asian population in the second or third decade of life with a male preponderance.[1] Hemogram characteristically reveals peripheral eosinophilia with raised serum IgE levels.[2] Our case presented with inguinal lymphadenopathy, which is a rare site of involvement. The histopathologic features seen with KD are preserved nodal architecture, follicular hyperplasia with florid germinal centers, eosinophilic infiltration of interfollicular areas, and proliferation of blood vessels.[3] Differential diagnoses include Hodgkin's lymphoma, epithelioid hemangioma, plasma cell Castleman's disease, and tuberculosis. Hodgkin's lymphoma may show eosinophilic infiltration of lymph nodes but Reed Sternberg cells are typically seen. Epithelioid hemangioma is difficult to differentiate from KD histopathologically, with the most prominent difference between the two being in their vasculature. Epithelioid hemangioma shows thick.walled blood vessels with concentric rings of fibrosis, and endothelial cells within the vessels appear eosinophilic with vacuolated cytoplasm having a characteristic hobnail appearance.[4]

Clinically, KD presents with lymphadenopathy, raised serum IgE levels, and is occasionally associated with nephrotic syndrome, ascites, and pleural effusion,[5] whereas epithelioid hemangioma presents with multiple, small dermal papular or nodular lesions which are seen in older patients and have a shorter duration.[4] Treatment options of KD include surgical excision or conservative management such as systemic or intralesional steroid, cytotoxic drugs, or radiotherapy.

The patient was started on oral prednisolone (40 mg), which was continued for 4 weeks till his eosinophil counts reverted back to normal levels and was gradually tapered off over 6 weeks. A single dose of injection triamcinolone 40 mg/ml was also given intralesionally.

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Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.