Walsh & Hoyt: Endocrine Myopathies

Skeletal muscle is an important endocrine target organ that may be damaged in certain metabolic disorders that occur in association with cancer. A steroid myopathy may develop in patients with ACTH-secreting tumors or tumors of the adrenal cortex, and thyrotoxic myopathy can occur in patients with thyroid gland carcinoma or small-cell lung cancer. In both of these conditions, the extraocular muscles may be affected. A particularly important, although rare, myopathy occurs in patients with carcinoid tumors.