Abstract
Background
Leiomyomas are benign cutaneous tumors of smooth muscle origin. Only a small percentage of leiomyomas arise in the head and neck region. We present the first case of leiomyoma arising in the sternothyroid muscle of the neck.
Case Report
We analyze the clinical presentation, pathology, and histology for a single case study. The histologic findings of the tumor located in the sternothyroid muscle support the diagnosis of leiomyoma.
Discussion
This is the first case of leiomyoma arising in the sternothyroid muscle, and only the second reported case of leiomyoma in the strap muscles of the neck.
Conclusion
Leiomyoma should be included in the differential diagnosis of soft tissue tumors in the head and neck region. A histological analysis is essential in determining both tumor type and subtype, which will inform the proper course of treatment.
1
Introduction
Leiomyomas are benign, soft-tissue tumors of smooth muscle origin that most commonly arise from the uterine myometrium, gastrointestinal tract, and skin . Leiomyomas account for less than 4% of all benign soft-tissue tumors . These tumors are usually solitary, slow growing, asymptomatic, and appear rounded and well demarcated .
Only around twelve percent of leiomyomas occur in the head and neck region, and they account for a low percentage of all head and neck tumors . The common treatment for leiomyoma of the head and neck is complete surgical resection, and recurrence is rare . To the best of our knowledge, we present the first case of leiomyoma arising in the sternothyroid muscle.
2
Case report
A 67-year-old woman with a history of thyroid nodules presented with a firm mass palpable on exam in the right anterior neck. An ultrasound of the neck showed bilateral non-suspicious nodules in the thyroid and a 10 × 7 × 8 mm rounded, hypoechoic right intramuscular lesion with coarse central calcification and no significant vascularity. An MRI of the head and neck showed an oval-shaped lesion measuring 14 × 10 × 10 mm of the sternothyroid muscle to the right of the midline at the level of the thyroid cartilage ( Fig. 1 ). The mass was isointense to skeletal muscle on T1-weighted series and slightly hyperintense to skeletal muscle on T2-weighted series.
A fine needle aspiration was performed with ultrasound guidance and revealed atypical follicular cells with nuclear enlargement and intranuclear inclusions. Due to its presentation as a noncontiguous mass, there was concern that this could be metastatic thyroid cancer and the decision was made to proceed with an excisional biopsy and a possible total thyroidectomy.
An inferior cervical excisional biopsy was performed with removal of the intramuscular mass ( Fig. 2 A ). The tissue specimen was described as a 0.8 × 0.5 × 0.4 cm tan-white calcified nodule ( Fig. 2 B). Histopathological examination revealed a leiomyoma with calcifications within the skeletal muscle ( Fig. 3 A ). Spindle cells with eosinophilic cytoplasm and blunt ended and elongated nuclei characteristic of leiomyoma were observed upon increased magnification ( Fig. 3 B). These features, along with a positive caldesmon immunostain ( Fig. 3 C), supported the diagnosis of leiomyoma with no evidence of malignancy.
2
Case report
A 67-year-old woman with a history of thyroid nodules presented with a firm mass palpable on exam in the right anterior neck. An ultrasound of the neck showed bilateral non-suspicious nodules in the thyroid and a 10 × 7 × 8 mm rounded, hypoechoic right intramuscular lesion with coarse central calcification and no significant vascularity. An MRI of the head and neck showed an oval-shaped lesion measuring 14 × 10 × 10 mm of the sternothyroid muscle to the right of the midline at the level of the thyroid cartilage ( Fig. 1 ). The mass was isointense to skeletal muscle on T1-weighted series and slightly hyperintense to skeletal muscle on T2-weighted series.
