Smooth muscle hamartoma (SMH) is an organoid malformation characterized by a painless hyperpigmented plaque with local hypertrichosis that is generally found on the trunk or proximal limbs, with lesions ranging from 2 to 10 cm in diameter. Histological examination reveals an increased density of smooth muscle bundles in the dermis and subcutis. Herein, we describe a Japanese patient with acquired SMH with Meyerson phenomenon. Histologically, a lymphoeosinophilic infiltrate in the dermis coexisted with the features of SMH.