ABSTRACT
BACKGROUND: Alveolar soft part sarcoma (ASPS) occurs most often in the deep muscles or fascia of the extremities in adults, with only 3.4% of these tumours originating from the head, face and neck. To date, only 17 cases of buccal ASPS have been reported, including the case presented here. Only one case of ASPS recurrence at the primary site, similar to our case, has been reported thus far. Immune checkpoint inhibitors (ICPis)-associated diabetes, with an estimated incidence of 0.43%, is usually seen in older cancer patients and has not been reported in younger people or in patients with ASPS. CASE PRESENTATION: A 24-year-old male patient presented with a slowly progressing right cheek mass with a clinical history of approximately 28 months. Sonographic imaging revealed a hypoechoic mass, which was considered a benign tumour. However, a pathological diagnosis of ASPS was made after excision of the mass. Five days later, functional right cervical lymph node dissection was performed. No other adjuvant therapy was administered after surgery. In a periodic follow-up of the patient six months later, blood-rich tumour growth was noted at the primary site, and Positron emission tomography-computedtomography (PET-CT) ruled out distant metastasis in other areas. The patient was referred to the Ninth People's Hospital of Shanghai Jiaotong University. Due to the large extent of the mass, the patient received a combination of a Programmed Cell Death Ligand 1(PD-L1) inhibitor and a targeted drug. Unfortunately, the patient developed three episodes of severe diabetic ketoacidosis after the administration of the drugs. A confirmed diagnosis of ICPis-associated diabetes was confirmed. After the second operation, the postoperative pathological diagnosis was ASPS, and the margins were all negative. Therefore, we made a final clinical diagnosis of ASPS recurrence at the primary site. Currently in the follow-up, the patient is alive, has no distant metastases, and undergoes multiple imaging examinations every 3 months for the monitoring of their condition. CONCLUSIONS: In analysing the characteristics of all previously reported cases of buccal ASPS, it was found that the clinical history ranged from 1 to 24 months, with a mean of approximately 3 to 9 months. Tumour recurrence at the primary site has been reported in only one patient with buccal ASPS, and the short-term recurrence in our patient may be related to the extraordinarily long 28-month history. ICPis-associated diabetes may be noted in young patients with rare tumours, and regular insulin level monitoring after use is necessary.
