Incidental Solitary Myofibroma in a Young Adult Female Patient: A Case Report and Comprehensive Literature Review of Myofibroma in Adults.

Myofibroma is a rare mesenchymal tumor typically observed in children, with only a few reported cases in adults. It can be easily mistaken for more common benign lesions, making it essential to include them in the differential diagnosis of soft tissue masses. This case report presents a rare instance of myofibroma in a young adult, and a comprehensive review of the literature presenting case reports and case series of myofibroma cases in the head and neck regions of adult patients aged > 18 years. A 22-year-old woman presented with a gradually enlarging, painless mass on the right side of her neck which had been developing over the course of two years. An ultrasound initially identified a 1×2 cm lipoma; however, during surgery, a fibrous soft tissue mass was discovered extending beneath the sternocleidomastoid muscle. The mass was found to be closely associated with the posterior auricular nerve. Despite its proximity to the nerve, the tumor was successfully excised, while preserving the nerve. Histopathological analysis confirmed a diagnosis of myofibroma. This case highlights the rare occurrence of myofibromas in adults and emphasizes the importance of considering this diagnosis when evaluating soft-tissue masses. Even when imaging suggests a benign lesion, surgical intervention may yield unexpected results. Accurate diagnosis through histopathology is essential, and careful surgical techniques, including nerve preservation, play a critical role in successful management. Long-term follow-up is necessary to ensure the absence of tumor recurrence.