dilated vascular channels with walls that are difficult to distinguish from the intervascular smooth muscle), with the solid type being the most common (67%). However, among angioleiomyomas limited to the head and neck region, the venous type is the most common. In the 2 cases described here, both patients were diagnosed with venous type angioleiomyoma. We presume that the tunica media of the STA had abnormally proliferated with thick muscular walls of varying size, because the tumor was directly linked to the STA. To the best of our knowledge, only 1 previous report has described a case of angioleiomyoma of the parotid gland, fed by the STA. 3 Clinically, angioleiomyoma usually presents as a painful, gradually growing mass. Tumors that present with pain are most frequently solid and occur in the extremities, whereas tumors in the head and neck region usually present without pain. 3,4,8 In the cases described here, both patients experienced no mass-related symptoms, including pain, but had insight regarding the growing mass. Parotid gland tumor accounts for ~3%-6% of all head and neck tumors, and is diagnosed according to clinical presentation, physical examination, radiological assessment, and FNA cytology. 1,2 However, preoperative diagnosis of head and neck angioleiomyoma is challenging because of its rarity and lack of definite radiological features. The radiological features detected by ultrasound, CT, and magnetic resonance imaging have several similarities with those of lipoma and vascular tumors. 3,10 Moreover, preoperative diagnostic FNA cytology does not provide sufficient clues, and can occasionally lead to a misdiagnosis of hemangioma or schwannoma. 3,10 Only total surgical excision followed by histological examination can fulfill the requirement for final diagnosis. Immunohistochemical stains for SMA, myosin, and desmin are useful for diagnosis, and CD34 and S100 protein are used to differentiate other types of spindle cell tumors. 3,10 In most cases, angioleiomyoma can be treated by simple total resection. It is usually possible to resect the mass without difficulty because the tumor is typically well encapsulated. In the 2 cases described here, the STA was completely ligated to prevent recurrence and to enable easy detachment of the tumor from the surrounding tissue.
CONCLUSIONWe report 2 cases of very rare angioleiomyoma discovered in the parotid gland, with the STA as the feeding vessel. It is difficult to make a certain diagnosis of angioleiomyoma with conventional preoperative diagnostic tools. Once a parotid tumor is discovered, although rare, the possibility of angioleiomyoma should be considered, and we recommend prompt surgical excision for accurate diagnosis and treatment.
