Salivary gland carcinomas are rare in childhood. A survey of salivary tumors from the Armed Forces Institut of Pathology [5] revealed that 1.3% of benign and 3% of malignant salivary gland tumors occurred in children [6,7].
Rhabdomyosarcoma represents 13 to 18% of head and neck tumors [8,9] and less than 1% of salivary gland cancers [10]; However, its exact frequency remains difficult to determine given the rarity of cases and the heterogeneity of the populations studied. In a series of 168 childhood salivary gland cancers, Krull’s et al. [11] reported six cases of rhabdomyosarcoma, i.e., 3.5%. Luna et al. [20] reported two cases of rhabdomyosarcoma out of 11 cases of primary sarcoma of the salivary glands. The largest published series of salivary rhabdomyosarcomas included three to 22 cases [12,13,6,14]
The parotid gland is the most frequent initial site of rhabdomyosarcoma before the submandibular and sublingual glands. Involvement of the accessory salivary glands remains exceptional [15]. Rhabdomyosarcoma is a high-grade malignancy tumor that affects subjects of all ages with a higher frequency in the first two decades of life, with, however, very broad extremes [16,6,17,18]
Parotid rhabdomyosarcoma usually presents as painful swelling of the parotid gland that rapidly increases in size [19,18]. Facial paralysis is a frequent sign, testifying to the aggressiveness and degree of tumor extension.
CT scans and magnetic resonance imaging (MRI) of the parotid are an essential contribution in terms of exploration of the parotid gland and evaluation of tumor extension to neighboring structures [20,21 ]. MRI seems to perform better with a sensitivity greater than 95% and a specificity greater than 75% [21]. A staging assessment combining pulmonary, hepatic and bone imaging is mandatory before any therapeutic decision. There is no universally accepted classification. Several are used, they are generally addressed to rhabdomyosarcomas without taking into account the localization [22–23].
Because of the aggressive nature of this tumor, treatment combines surgery, radiation therapy, and chemotherapy. Indications and relevance depend on classification, resection quality, and anatomic pathology findings; surgery is the cornerstone of treatment. It includes partial or total parotidectomy, with or without facial nerve preservation, according to the Gustave Rousey Institute classification, which is stage I and II cases and first-line treatment classification according to IRS group I and II cases (Intergroup Rhabdomyosarcoma study)[ 24,23], radiotherapy is indicated for incomplete resection and/or histological lymph node invasion, and the radiation field must include the parotid gland where the tumor is located and the cervical-subclavian lymph node region (if involved).For persistent tumors and/or lymph node invasion with capsular rupture, a dose of 60 to 70 Gray is recommended. Due to their activity on salivary gland tumors and sarcomas [25,5,26];Adjuvant chemotherapy could improve local control and survival rates, but this remains to be demonstrated. Neoadjuvant chemotherapy could find its interest in locally advanced and/or inoperable tumors (stage III of the classification of the Gustave-Rousey Institute and group III of the IRS) by making them accessible to cardiological surgery.
Salivary rhabdomyosarcomas have a tendency to local recurrence, the time to onset is on average nine months [23]. Pulmonary, hepatic and bone metastases are frequent, tumor dissemination can also occur towards the cerebrospinal fluid after invasion of the meninges. The time to onset is on average nine to 36 months [27]. Survival rates are variable. From 22 cases, Pappas et al. reported a two-year disease-free survival rate of 63% after chemotherapy, radiotherapy and surgery [13], whereas Flammant et al. reported an overall survival rate of 68% and five-year disease-free survival of 53% [14]. For Cullender et al., five-year survival is 60% in the case of chemotherapy and radiotherapy [19].
The stages or groups of classifications are major prognostic factors since in the IRS study, the five-year survival rates for groups I to IV were 83, 70, 52 and 20% respectively [28]. ; According to the Gustave-Rousey Institute, the five-year survival rates for stages I and II, III and IV were respectively 80, 53% and almost 0% [13,23]; Other prognostic factors have been analyzed, in particular the histological type: the more differentiated the tumor, the better the prognosis, the three-year survival rate is 60% in the botryoid forms and 40% for the for- my embryonic and alveolar. Due to more frequent lymph node invasion, the latter form has a 50% prognosis compared to 17% for the other forms [29]. The most important unfavorable prognostic factors for Cullender et al. are age (55% five-year survival rate for children under seven years old and 33% for children over seven years old), alveolar type, and tumor size greater than 5 cm [19].
