Distant skeletal muscle metastasis to sternocleidomastoid in the setting of recurrent papillary thyroid carcinoma.

Papillary thyroid carcinoma (PTC), the most common form of differentiated thyroid cancer, is characterized by an indolent course and excellent prognosis. Although its spread to regional lymph nodes is well known, distant metastases are seen only in a minority of patients with lungs being the most common site. Skeletal muscle metastases are extremely rare even in follicular thyroid carcinoma, in which hematogenous spread is known to occur. We describe a case of skeletal muscle metastasis to sternocleidomastoid muscle in a case of PTC in the setting of local recurrence. [ABSTRACT FROM AUTHOR]