Parapharyngeal sialoblastoma: Systematic literature review

A 2-year-old female presented with an enlarging right parotid mass that was reported as a sialoblastoma on initial incisional biopsy. She underwent subsequent total parotidectomy and infratemporal fossa clearance with adjuvant chemotherapy. At 5-year follow-up, she is disease-free having undergone costochondral TMJ reconstruction and facial nerve reanimation. Sialoblastoma is a rare salivary gland tumour typically presenting in early childhood. This study aims to review the available literature on sialoblastomas to inform contemporary practice. A systematic review was performed to identify articles describing cases of sialoblastoma for extraction of data regarding presentation, investigation, management and outcomes. Sixty-six articles describing 92 cases were included. Age at initial presentation ranged from birth to 83 years with 70.3% of patients aged one year or younger with no sex predilection. Tumours were most commonly in the parotid region followed by submandibular region. Imaging features are generally benign due to a lack of infiltrative borders. Surgery is the usual first line treatment. Eleven patients had metastasis, and six had synchronous hepatoblastoma. Patients were followed for an average of 4.4 years with seven reported deaths and 23 recurrences on average 18.1 months after initial treatment. Sialoblastoma should be considered as a differential diagnosis in infants or toddlers presenting with a salivary gland mass. Tissue diagnosis should be established prior to complete onocologic resection with adjuvant chemotherapy if indicated. Additionally, patients should be screened for synchronous hepatoblastoma due to high rate of synchronicity. Close oncosurveillance is recommended due to high recurrence.