Plasma cell dyscrasia: a case of POEMS syndrome with a unique dermatologic presentation.

POEMS (polyneuropathy, organomegaly [hepatosplenomegaly or lymphadenopathy], endocrinopathy, M protein, and skin changes) syndrome is an uncommon plasma cell dyscrasia with diverse manifestations, including lymphadenopathy as well as those that comprise the acronym. Dermatologic changes may include hyperpigmentation, thickened skin, hypertrichosis, and papular angiomas. These changes are believed to result from humoral products of the plasma cell clone and frequently resolve with treatment of the neoplasm. We describe a man with typical POEMS syndrome with a unique skin lesion: a large, sharply circumscribed, pigmented plaque on the anterior chest wall centered over a plasmacytoma of the sternum. Results of histologic examination showed a proliferation of capillaries of varying size, enlarged fibroblasts, and increased amounts of collagen and proteoglycan from the dermis to the periosteum. Because the outer cortex of the sternum was eroded, peptide mediators of vascular and fibroblast proliferation may have diffused directly from the plasma cell lesion into the tissues of the chest wall.