Obesity-associated lymphedematous mucinosis and stasis mucinosis.

Cutaneous dermal mucinoses are a group of conditions characterized by abnormal deposition of mucin (hyaluronic acid and sulfated glycosaminoglycans) in the dermis. They can be classified either as localized or generalized forms and occur primarily or secondarily to systemic disorders. Obesity-associated lymphedematous mucinosis and pretibial stasis mucinosis are uncommon and relatively newly recognized disorders occurring in obese patients or in patients with venous insufficiency. Clinically, patients present with papules and nodules progressing to plaques and arising in an erythematous and edematous basis on the legs, especially the shins. Histopathologic examination indicates mucin deposition in the superficial portion of the dermis, angioplasia with an increase in small blood and/or lymphatic vessels, vertically running vessels, slight fibrosis, and no inflammation. Laboratory workup and histopathologic testing are helpful in differentiating these entities from pretibial myxedema (thyroid dermopathy), which represents the main differential diagnosis. Obesity-associated lymphedematous mucinosis and stasis mucinosis are not different entities but belong to a spectrum of mucinoses secondary to an increased body mass index, chronic lymphedema, and/or chronic venous insufficiency.