Kikuchi-Fujimoto Disease Masquerading as Metastatic Papillary Carcinoma of the Thyroid.

Kikuchi-Fujimoto disease also known as histiocytic necrotizing lymphadenitis is a rare cervical inflammatory lymphadenitis that is most commonly seen in young Asian women. It is mainly characterized by lymphadenopathy, hepatosplenomegaly, fever, nocturnal sweats, myalgia, weight loss, and arthralgia, and commonly follows a self-limited course. The differential diagnosis is challenging as many other conditions such as malignant lymphoma, metastatic disease, tuberculosis and infectious lymphadenopathies can present in a similar way. We present an unusual case of Kikuchi-Fujimoto disease masquerading as metastatic papillary carcinoma of the thyroid. A 30-year-old young female presented, 2 months post-partum, with complaints of neck pain and fever. A computed tomography scan showed enlarged right-sided lymph nodes and a thyroid nodule. Subsequent biopsy of a thyroid nodule revealed papillary thyroid carcinoma and reactive inflammation in one of the lymph nodes. She underwent an elective total thyroidectomy, central node dissection and a right modified lymph node dissection for enlarged lymph nodes. Her recovery was uneventful and the pathology report was consistent with a papillary carcinoma of the thyroid with one lymph node positive for metastatic disease and several other lymph nodes showing histiocytic necrotizing lymphadenitis. This coexistence of Kikuchi-Fujimoto disease with localized metastatic papillary thyroid cancer is unusual and presents an interesting, challenging, and complex management dilemma.