悪性疾患との鑑別を要した頸部軟部組織アミロイドーマ例

抄録

Amyloidosis comprises a diverse group of disorders characterized by the deposion of amyloid protein in various organs and extracellular tissues. Clinically, it has been classified into systemic and localized forms. Amyloidoma, a very uncommon presentation of amyloidosis, could be defined as a solitary localized tumor-like deposit of amyloid in the absence of systemic amyloidosis. We present a case report of amyloidoma of the neck in an 83-year old man with laryngeal carcinoma. Localized deposits of amyloid occurring throughout the upper aerodigestive tract have been described, but such deposits have rarely been reported in the soft tissues of the neck.
On physical examination, an immobile and elastic hard mass was palpable in the neck. A CT of the neck region revealed a poorly enhancing mass in the right submandibular region. On MRI, the mass was visualized as a hypointensity on both T1 and T2-weighted images. ¹⁸FDG PET-CT revealed a high FDG uptake in the mass, with a maximum standardized uptake value (SUV_max) of 5.9. The mass was surgically removed. Histopathological examination revealed AL amyloidosis. Systemic amyloidosis was excluded by several examinations. The patient was still disease-free at the 12-month follow-up.