DISCUSSION 
Salivary glands are frequently located in the parotid gland which is why the majority of neoplastic processes and hemangiomas are studied at that level(7,8). Hemangiomas are mesenquimalbenigns tumors and usually presents as a unilateral hard mass (7). Within the parotid, it has been described that 5% of benign tumors from this gland are hemangiomas which is considered to be a rare tumor type (8). Diagnosis can be challenging in this type of tumors, however it gets even difficult and rare when it presents at the sublingual area, that usually compromise the upper airway due to late diagnosis. (9)
Less than 20 submandibular benign tumor cases have been reported in literature, between removable and biopsied lesions, it was found that hemangiomas represented 1.7% of the cases (11). Clinical course varies, and the majority presents only with pain or minor symptoms (11), but can also present with recurrent upper respiratory infections (12) or severe complications such as described in our case.
The diagnosis can be arduous in this type of benign tumors especially due to their localization (10). Previous studies in parotid glands show the efficacy of doppler ultrasound as first diagnostic step, followed by MRI-imaging where further details can be seen (13). In our case, ultrasound was highly beneficial to the diagnosis of hemangioma.
Some differential diagnosis can have similar clinical presentations such as hemangioendotheliomas (14, 15), these are benign tumors with the same origin as hemangiomas, but haschronic lesions and syndromes associated (14). The presentation of this tumor is very rare and usually grows within the submandibular triangle, where also pleomorphic adenomas can be located (16). In our case, the submandibular hemangioma was found in the submandibular triangle as well. Hemangiomas can grow extensively and it can generate severe dysphagia (17), however this compromise may become worse with acute respiratory distress and cardiac arrest due to severe respiratory failure as happened to our patient.
Treatment has changed recently, according to a 40 years cohort study, steroids and surgery have been well-tolerated by patients with excellent response and very few adverse effects (18). Nowadays, majority of hospitals follows a regimen based on oral propanolol which is usually well tolerated as well (19).
In our case our patient followed this last regimen and up to this date there has not been any issues so far.
As a conclusion; our patient had a hemangioma in a very rare location with few previous reports. She had a severe complication managed in the hospital with no recurrences or complications until today.