Objective: Aggressive fibromatosis, also known as desmoid fibromatosis, desmoid tumor, well-differentiated non-metastatic fibrosarcoma, and type Ⅰ fibrosarcoma, is a rare and aggressive form of fibromatosis. AF was first proposed and definitively diagnosed by Stout in 1954. In 2013, WHO classified it as a locally aggressive intermediate tumor of fibroblast/myofibroblast tumors, which can be divided into three types: extra-abdominal type, abdominal wall type and intra-abdominal type. AF occurring in the head and neck belongs to a subtype of extra-abdominal type, which is extremely rare, accounting for about 6%-8% of total AF. Its high recurrence rate and absence of distant metastasis are notable features. This article reports a case of an elderly patient with rare huge AF in the head and neck (extraabdominal type) who was admitted to our department. The clinical diagnosis and treatment process and short-term prognosis of MDT collaboration were summarized and analyzed. Methods: A female patient, 86 years old, was diagnosed with a huge neck mass for 5 years. Puncture biopsy showed aggressive fibromatosis. Severe arrhythmia, multifocal premature ventricular contractions with double and triple beats were found before surgery. Results: There were no postoperative complications in the patients. The spindle cells arranged in fasciculation were mild in morphology, with loose or vacuolated nuclear chromatin, small nucleoli, Beta-catenin (focally +), LEF-1(focally +),S-100(-),Ki67 (about 5% in hot area). FISH showed CTNNB1(3p22) gene deletion (+), which was consistent with aggressive fibromatosis. The patient was discharged without radiotherapy or chemotherapy. There was no recurrence during a short-term follow-up of half a year. Conclusions: Giant AF in head and neck (extraabdominal type) is rare and has no specific clinical manifestations. The tumor is invasive and prone to recurrence. Due to the advanced age and long-term severe arrhythmia, the best opportunity for surgery was missed when the tumor volume was small, and radiofrequency ablation was performed, resulting in the tumor volume increased rapidly in the stimulated state. Our team formulated the optimal diagnosis and treatment plan after sufficient MDT discussion during the perioperative period. Complete resection of the tumor on the basis of ensuring perioperative safety has achieved obvious clinical effect and maximum benefit of treatment.