[A case of malignant amygdaloid cyst].

INTRODUCTION: An amygdaloid cyst is a rare high laterocervical cystic tumor arising from the second branchial cleft. It accounts for 2% of laterocervical tumors and up to 85% of second branchial cleft abnormalities [1]. The incidence of intracystic squamous cell carcinoma ranges from 4 to 22% [2]. The diagnosis of primary carcinoma or intracystic metastasis is a controversial issue. We report a rare case of degenerate amygdaloid cyst meeting the diagnostic criteria for intracystic squamous cell carcinoma determined by Martin and Khafif. OBSERVATION: A 73-year-old female patient consulted for a left cervical swelling in 2010; the diagnosis was an amygdaloid cyst. She had a history of squamous cell carcinoma of the hard palate (T1NoMo) surgery and radiation therapy in 2009, without recurrence. Three years later, the swelling increased to a large size without any cervical node involvement. An exploratory cervicotomy with histological study revealed intracystic squamous cell degeneration. DISCUSSION: Primary squamous cell carcinoma location in the wall of an amygdaloid cyst is extremely rare and a highly controversial issue. The challenge is to be able to discriminate between a cystic metastasis of squamous cell carcinoma of the aerodigestive tract and a primary squamous cell carcinoma located in the wall of an amygdaloid cyst. Martin and Khafif defined specific criteria to confirm the diagnosis of primary branchiogenic carcinoma.