Kimura disease: a case report of a rare illness presenting as a common complaint.

Background Kimura is an uncommon inflammatory cause of pediatric head and neck masses due to eosinophilic infiltration of unclear etiology. Kimura can present similarly to infectious lymphadenitis, a much more common pediatric complaint. This case explores the role of anchoring bias when faced with an illness that at first appears to fit a common illness script that led to a delayed diagnosis. Case presentation A 7-year-old boy presented with acute onset of pre-auricular lymphadenopathy and fevers initially thought to be most consistent with infectious cervical lymphadenopathy. Despite treatment with broad spectrum antibiotics and multiple evaluations for underlying abscess requiring surgical drainage, the patient did not improve and remained febrile. Eventually, excisional lymph node biopsy was obtained and a pathologic diagnosis of Kimura disease was made. Conclusions This case illustrates an uncommon pediatric diagnosis which presented similarly to infectious cervical lymphadenitis without additional laboratory features consistent with Kimura. We highlight the role of anchoring bias and care fragmentation leading to repeat imaging and delayed biopsy in the eventual diagnosis of a rare illness.