Three cases of dermatomyositis associated with papillary thyroid cancer.

OBJECTIVE

Dermatomyositis (DM) is considered a paraneoplastic phenomenon and cancer may precede or follow the development of clinical features by several years. Despite the prevalence of thyroid cancer, reports of an association are rare. We report 3 cases of dermatomyositis and thyroid cancer, focusing on the clinical course of the rheumatologic condition following thyroidectomy. We also performed a comprehensive review of the current literature.

METHODS

We performed a chart review between 1960 and 2012 to identify patients with DM and papillary thyroid cancer (PTC) seen in Mayo Clinic, Rochester, in Minnesota, a tertiary referral center. Only 3 patients were identified using the above criteria.

RESULTS

There was a significant improvement in the course of the dermatological condition after definitive treatment for thyroid cancer (i.e. thyroidectomy) in one of our patients. The risk of a first malignancy is highest at the time the diagnosis of dermatomyositis is made and remains significantly higher in the first two years following diagnosis. A comprehensive literature review identified only two patients with PTC and dermatomyositis (both in Taiwan) across 4 international population cohorts. In addition, several cases have been reported from patients in the Far East, a geographical predilection that is unexplained.

CONCLUSIONS

Our case series highlights the uncommon association between thyroid cancer and dermatomyositis while illustrating prevailing knowledge about the temporal relationship between dermatomyositis and thyroid cancer. Increased vigilance for and treatment of thyroid cancer in patients with dermatomyositis may assist in the successful management of this difficult rheumatologic condition.