Isolated unilateral temporalis muscle hypertrophy (IUTMH) is a rare clinical entity, with fewer than 20 cases reported globally. This case report and literature review aimed to expand the understanding of its diagnosis, management, and outcomes. A 44-year-old Arab Asian woman presented with a 12 month history of progressive left temporal swelling and pain during mastication. Clinical examination revealed a firm, non-tender mass. Imaging [computed tomography (CT) and ultrasonography] confirmed isolated left temporalis muscle hypertrophy without neoplastic or inflammatory features. Botulinum toxin type A (Btx A, 25 U) injection led to symptom improvement and partial muscle reduction at 3 month follow-up. A literature review of 16 published cases (including ours) demonstrated a slight female predominance (10/16), variable symptom profiles (painless swelling to masticatory dysfunction), and diverse management strategies. Minimally-invasive Btx A achieved favorable outcomes in 6/16 cases, with lower doses (25 U) showing efficacy comparable with higher doses. Surgical intervention, although effective, was associated with recurrence in 1 case. Diagnostic reliance on imaging (CT/magnetic resonance imaging) and histology (when performed) confirmed hypertrophy without malignancy. While bruxism and stress were implicated in some cases, 7/16 lacked identifiable triggers, suggesting multifactorial etiology. Long-term follow-up data remain limited, underscoring the need for vigilant monitoring. This case reinforces Btx A as a primary therapeutic option and highlights the importance of individualized management in IUTMH. Further research is warranted to elucidate pathogenesis and optimize treatment protocols.

Keywords: IUTMH; clinical findings; isolated unilateral temporalis muscle hypertrophy; outcomes; review; treatment.

孤立性单侧咬肌肥厚（IUTMH）是一种罕见的临床状况，全球报道的病例不到20例。本案例报告和文献回顾旨在扩大对其诊断、管理和预后的理解。一名44岁的阿拉伯亚洲女性患者，因左侧颞部肿胀并伴有咀嚼痛12个月而就诊。体检发现了一个坚硬但无触痛的肿块。影像学检查（包括CT和超声）确认了孤立性左咬肌肥厚，且未见肿瘤或炎症特征。肉毒杆菌毒素A（Btx A，25 U）注射后，在3个月随访时症状有所改善，并伴有部分肌肉萎缩。对16例已发表病例（含本案例）的文献回顾显示，女性略占多数（10/16），症状表现多样（无痛性肿胀至咀嚼功能障碍），管理策略也有所不同。微创Btx A治疗在其中6个案例中取得了良好效果，较低剂量（25 U）与较高剂量的效果相当。虽然手术干预有效，但在一例中出现了复发情况。诊断主要依赖于影像学检查（CT/磁共振成像）和病理学检查（如有进行），这些都确认了肌肉肥厚而无恶性病变的存在。尽管在某些病例中提到咬合症和压力为潜在触发因素，但有7/16的案例缺乏可识别的诱因，提示多因素病因的可能性。长期随访数据仍有限，强调了需持续监测的重要性。此案例进一步证实了Btx A作为主要治疗选项的有效性，并突显了个别化管理在IUTMH中的重要性。需要更多的研究来阐明其发病机制并优化治疗方案。

关键词：IUTMH；临床发现；孤立性单侧咬肌肥厚；预后；综述；治疗。