Kimura disease: A rare case affecting the inguinal lymph node.

BACKGROUND

Kimura disease (KD) is a benign, chronic inflammatory disorder first described by Kimm and Szeto in 1937, with further details provided by Kimura in 1948. It typically presents as unilateral subcutaneous masses in the head and neck, particularly post-auricular, affecting lymph nodes, soft tissues, and salivary glands. The aetiology is uncertain but may involve hypersensitivity or immune responses. Diagnosis relies on histological examination showing eosinophilic infiltration and lymphocyte proliferation. The exact cause remains unclear, though hypersensitivity or immune mechanisms have been suggested. KD is extremely rare in the inguinal region, and awareness of such atypical presentations is crucial to avoid misdiagnosis.

CASE PRESENTATION

We report a case of an elderly woman who presented with a painless, slow-growing inguinal mass. Clinical and radiological evaluations suggested a benign lesion, but malignancy could not be ruled out. A biopsy confirmed the diagnosis of Kimura disease, revealing characteristic eosinophilic infiltration and lymphoid proliferation. The patient underwent surgical excision followed by corticosteroid therapy. She recovered well and remained asymptomatic during an 18-month follow-up period.

DISCUSSION

Kimura disease predominantly affects young Asian men, with very few reported cases in elderly women or in the inguinal region. It can mimic malignant or infectious conditions, making histopathological confirmation essential. Imaging aids in ruling out other differential diagnoses, but biopsy remains the gold standard. Treatment options include surgical excision, corticosteroids, and immunosuppressive therapy. Our case emphasizes the importance of considering KD in unusual locations and patient demographics.

CONCLUSION

This case underscores the need for awareness of atypical presentations of Kimura disease. Early recognition and appropriate management can prevent unnecessary interventions and misdiagnosis. Surgical excision combined with corticosteroid therapy was effective, leading to an uneventful recovery.

CASE PRESENTATION

A 70-year-old Chinese woman with underlying hypertension and ischemic heart disease (on clopidogrel 75 mg daily) presented with a painless lump over the right inguinal region, which had appeared three months prior. The swelling was intermittent without discharge, fever, weight loss, or systemic symptoms. She had no history of malignancy, tuberculosis, recent infections, or trauma. Examination revealed a 2 × 2 cm, firm, mobile, non-tender swelling over the right inguinal region. No other lymph nodes were palpable. A two-week course of empirical antibiotics (amoxicillin-clavulanate 625 mg TID) resulted in temporary resolution, but the swelling recurred a month later. Ultrasound revealed an enlarged lymph node with preserved architecture, while CT abdomen and pelvis showed non-necrotic lymphadenopathy without hepatosplenomegaly. Serum IgE was elevated at 1200 IU/mL. No other lymphadenopathy was detected in the neck, axilla, or other catchment areas. Fine-needle aspiration cytology (FNAC) was inconclusive, leading to surgical excision of three lymph nodes. Histopathological examination confirmed Kimura disease, showing follicular hyperplasia with eosinophilic infiltration and vascular proliferation. Postoperatively, she received oral prednisolone (30 mg daily for 4 weeks, tapered over 3 months). At the 18-month follow-up, she remained asymptomatic without recurrence.