Dermatomyositis and mucinosis

Background Mucin deposition is a common feature in autoimmune collagen dise ases including dermatomyositis. Nevertheless, clinical manifestations of mu cinosis are uncommon in patients with dermatomyositis. Two cases of mucinos is associated with dermatomyositis are reported. Patients A 53-year-old woman presented with symmetrical plaques on the uppe r limbs formed by the coalescence of small, violaceous papules. In addition , she showed the typical cutaneous and muscle features of dermatomyositis. A 44-year-old woman with dermatomyositis of 5 years' evolution developed li near, flesh-colored papules across the flexural creases of her palms and fi ngers. Results Skin biopsy of the upper limb lesions in the first patient showed e pidermal changes compatible with dermatomyositis and dermal mucin depositio n. Histopathologic examination of the palmar lesions of the second patient showed less intense epidermal changes of dermatomyositis and dermal mucin d eposition. Conclusions Mucin deposition in patients with dermatomyositis may have an u nusual clinical presentation, and it should be considered in the differenti al diagnosis of atypical cutaneous lesions in these patients.