Case Presentation: A 51-year-old female presented with a three month history of migratory rash and weakness. Initially, she developed periorbital swelling, eyelid discoloration, and a migrating pruritic erythematous rash. The rash originated on her upper arms and thighs progressing to her chest, back, and face. She reported muscle weakness, most notably an inability to lift her arms and difficulty with climbing stairs and getting out of a chair. Review of systems was significant for a fifteen pound weight loss in three months. Also, she described a two week history of dysphagia to solids and liquids. Upon presentation, physical exam revealed tachycardia, malar rash including nasolabial folds, periorbital swelling with violaceous discoloration above eyelids, erythematous rash on chest, shoulders, and posterior back, and proximal muscle weakness (strength 3/5 in deltoids and thighs). Exam was also remarkable for palpable left breast mass with axillary lymphadenopathy. Labs revealed CK 6000 U/L, AST 419 U/L, ALT 202 U/L, LDH 845 U/L. CT Chest revealed 2 x 2 x 4 cm spiculated left breast mass with left axillary lymphadenopathy, findings suspicious for breast malignancy. Also, with ANA+ (1:320 titer), aldolase + (91 U/L), and anti-Jo negative. With the history and physical findings, paraneoplastic dermatomyositis (DM) in the setting of suspected breast cancer was presumed. She was treated with high dose steroids and IVIG. There was improvement in CK levels and in strength. She has planned definitive treatment for breast cancer as outpatient which should resolve DM symptoms.

Discussion: Dermatomyositis (DM) is usually a rare idiopathic autoimmune myopathy with the incidence of 1:100,000. However, in an adult with new onset DM, it is suspected that approximately 30% of cases are associated with an underlying malignancy; thus, the diagnosis of DM should result in further work up for an undiagnosed malignancy. Though paraneoplastic DM is usually associated with Non-Hodgkin lymphoma, ovarian, lung, and gastrointestinal cancers, the incidence of breast cancer associated DM may be up to 20% of cases. Though not as commonly associated with paraneoplastic DM, breast cancer is the most common malignancy in women; thus, it is important to perform a breast exam as part of the work up. Clinical factors that may increase risk of paraneoplastic DM include dysphagia, negative auto-antibodies, and older age of onset. Treatment of DM includes high dose steroids and possibly IVIG if severe symptoms including dysphagia are present. In cases of paraneoplastic DM, the definitive treatment of the underlying malignancy should resolve DM symptoms.

Conclusions: Age appropriate cancer screenings should be performed in the setting of new adult onset dermatomyositis (DM). Common malignancies may be a predisposition to develop paraneoplastic DM. Recognition of the constellation of symptoms of DM, including proximal muscle weakness, dysphagia from bulbar weakness, and skin manifestations such as Gottron’s papules, V-sign, shawl sign, and heliotrope rash with periorbital swelling, may aid in establishing this diagnosis.