A pediatric nasopharyngeal carcinoma masquerading as Kimura disease: a rare case report from Nepal

Nasopharyngeal carcinoma (NPC) is an epithelial malignancy of the nasopharyngeal mucosa, most often arising in the fossa of Rosenmüller. While exceedingly rare in children under 10 years, it shows a male predominance.

A 9-year-old male presented with bilateral cervical lymphadenopathy persisting for 1 year. Initially, unilateral right-sided neck swelling progressed to bilateral involvement with a left-sided mass. Trucut biopsy showed features consistent with Kimura disease. Repeat ultrasound-guided lymph node biopsy revealed an Epstein-Barr virus (EBV)-positive non-keratinizing metastatic carcinoma, suggestive of NPC, further confirmed by immunohistochemical analysis. Treatment with neoadjuvant platinum-based chemotherapy, followed by radiotherapy, achieved a complete clinical response at 6 months.

This case demonstrates a critical diagnostic pitfall where pediatric NPC initially masqueraded as Kimura disease due to inflammatory-predominant tissue sampling. The diagnostic breakthrough came through repeat ultrasound-guided biopsy with comprehensive immunohistochemical analysis and EBV-encoded RNA in situ hybridization, confirming EBV-positive non-keratinizing NPC. Multimodal imaging (CT/MRI/PET) established T2N3M0 staging. After neoadjuvant platinum-based chemotherapy followed by conformal radiotherapy, a complete clinical response at 6 months was achieved. In resource-limited settings, prioritizing repeat targeted biopsy, tissue-based EBV detection, and conformal radiotherapy offers an effective diagnostic and therapeutic pathway for this rare but treatable childhood malignancy.

In a resource-limited setting like Nepal, for the early diagnosis and treatment of NPC, a combination of novel testing methods and a high index of suspicion in a patient with unilateral or bilateral neck swelling is necessary.