This chapter examines plasma cell neoplasms and paraproteinemias with a focus on their cutaneous manifestations. It categorizes these conditions into direct cutaneous involvement by plasma cell neoplasms, reactive plasma cell hyperplasias, and skin lesions associated with paraproteinemias. The chapter provides detailed insights into conditions like solitary cutaneous plasmacytoma, extramedullary cutaneous multiple myeloma, and systemic disorders such as cryoglobulinemia and amyloidosis that manifest in the skin. Diagnostic challenges are highlighted, emphasizing the integration of clinical, histopathological, and laboratory findings to distinguish benign mimics from malignant conditions. Management strategies are discussed, ranging from localized treatment for isolated lesions to systemic therapies for conditions with significant extracutaneous involvement, underscoring the importance of a multidisciplinary approach.