BACKGROUND: Hoffmann\'s syndrome is a rare form of hypothyroid myopathy in adults, which is mainly characterized by muscular weakness and muscular pseudohypertrophy.
METHODS: We report about a 61-year-old Western European man with myalgia, myxedema and pseudohypertrophy of the calf muscles. Laboratory tests revealed significantly elevated thyroid stimulating hormone (TSH) and creatine kinase (CK). Muscle MRI showed muscular hypertrophy of the lower limbs, but no signs of myositis or myopathy (no gadolinium enhancement, no edema, no fatty degeneration). In addition, electromyography (EMG) detected spontaneous activity. After the beginning of thyroxin-therapy it took six months until the muscle weakness improved and the myalgia regressed.
CONCLUSIONS: Here, we focus on diagnostic routines and typical findings to differentiate Hoffmann\'s syndrome from other myopathies. Clinical hallmarks of Hoffmann\'s syndrome are pseudohypertrophy and weakness of the calf muscles in combination with elevated CK and elevated TSH. EMG is well suited to detect the involvement of the muscles and muscle MRI helps to differentiate it from other myopathies. Hoffmann\'s syndrome is a rare myopathy due to hypothyroidism and plays a role in the differential diagnosis of myopathic complaints even if hypothyroidism has not been detected before.

BACKGROUND: Hoffmann\'s syndrome is a rare form of hypothyroid myopathy. Only a few cases of fasciotomy in this setting have previously been reported.
METHODS: A 41-year-old Caucasian man under treatment for hypothyroidism presented with acute-onset severe pain in his forearm for no obvious reason and was admitted to our emergency room. He eventually developed compartment syndrome which necessitated surgical decompression. Soon after surgery he complained of similar symptoms in his calves. By the time his hypothyroid status was confirmed, conservative treatment and orally administered levothyroxine gradually made the pain from his calves disappear, without further surgical treatment.
CONCLUSIONS: Hoffmann\'s syndrome may precipitate a compartment syndrome in the absence of trauma.

Hypothyroidism is a common endocrine disease with characteristic symptoms and signs such as fatigue, weight gain, intolerance of cold, constipation, depression, mental slowdown and muscle cramps. Myopathic changes are observed in 30-80% of patients with hypothyroidism, but muscular hypertrophy with muscle stiffness has been reported in less than 10% of patients. Hoffmann\'s syndrome is a specific form of the hypothyroid-associated myopathy, rarely seen. Symptoms of this syndrome include proximal muscle weakness, hypertrophies in extremities, stiffness, muscle cramps, spontaneous muscle pain; and are associated with increased muscle enzymes. These findings can be seen at any time during hypothyroidism. Hofmann\'s syndrome has a very good prognosis. Its response to hormone replacement therapy is very good. Therefore, in patients with myopathy-like symptoms, considering in the differential diagnosis that the myopathy may be a reflection of hypothyroidism will facilitate the diagnosis and treatment. In this case, we aimed to present together Hashimoto thyroiditis and muscular hypertrophy, which is an atypical presentation of hypothyroidism and rarely seen in the literature, namely Hoffmann\'s syndrome.

Abnormalities in thyroid function are common endocrine disorders that affect 5-10 % of the general population, with hypothyroidism occurring more frequently than hyperthyroidism. Clinical symptoms and signs are often nonspecific, particularly in hypothyroidism. Muscular symptoms (stiffness, myalgias, cramps, easy fatigability) are mentioned by the majority of patients with frank hypothyroidism. Often underestimated is the fact that muscle symptoms may represent the predominant or the only clinical manifestation of hypothyroidism, raising the issue of a differential diagnosis with other causes of myopathy, which sometimes can be difficult. Elevated serum creatine kinase, which not necessarily correlates with the severity of the myopathic symptoms, is certainly suggestive of muscle impairment, though it does not explain the cause. Rare muscular manifestations, associated with hypothyroidism, are rhabdomyolysis, acute compartment syndrome, Hoffman\'s syndrome and Kocher-Debré-Sémélaigne syndrome. Though the pathogenesis of hypothyroid myopathy is not entirely known, proposed mechanisms include altered glycogenolytic and oxidative metabolism, altered expression of contractile proteins, and neuro-mediated damage. Correlation studies of haplotype, muscle gene expression and protein characterization, could help understanding the pathophysiological mechanisms of this myopathic presentation of hypothyroidism.

Hoffmann\'s syndrome is a hypothyroid myopathy presenting as muscle stiffness and hypertrophy. It is a rare complication of hypothyroidism. MRI features of this syndrome have seldom been described in the literature. We present a case of Hoffmann\'s syndrome in a 34-year-old man who underwent lower extremity contrast-enhanced MRI. MRI can demonstrate the hypertrophic configuration, T2 hyperintensity, and enhancement of the involved muscles in Hoffmann\'s syndrome. Along with clinical, laboratory, and electromyography findings, MRI may be helpful in distinguishing between inflammatory myopathy, myonecrosis, subacute muscle denervation, and infectious myositis.