Adenopathy and extensive skin patch overlying plasmacytoma syndrome—the clue to early diagnosis of polyneuropathy, organomegaly, endocrinopathy, monoclonal gammopathy, and skin changes: A case series and literature review

IMPORTANCE: Adenopathy and extensive skin patch overlying plasmacytoma syndrome is a paraneoplastic syndrome characterized by a cutaneous vascular patch overlying a plasmacytoma and systemic manifestations. It is thought to be an early stage of polyneuropathy, organomegaly, endocrinopathy, monoclonal gammopathy, and skin changes syndrome, which is a rare, but potentially fatal multisystemic disease that is associated with plasma cell dyscrasia. Thus, a high index of suspicion is required to identify patients with adenopathy and extensive skin patch overlying plasmacytoma as they may present with early polyneuropathy, organomegaly, endocrinopathy, monoclonal gammopathy, and skin changes, which is curable if detected early. OBJECTIVE: To report additional cases of adenopathy and extensive skin patch overlying plasmacytoma syndrome, describe dermatoscopic and histologic findings of the cutaneous patch and review all up to date literature on adenopathy and extensive skin patch overlying plasmacytoma syndrome. DESIGN: Case series from a single tertiary care center. PARTICIPANTS: Here, we present the second case series of three patients with adenopathy and extensive skin patch overlying plasmacytoma syndrome who all meet the diagnostic criteria for polyneuropathy, organomegaly, endocrinopathy, monoclonal gammopathy, and skin changes. The diagnosis was suspected based on the presence of the violaceous cutaneous patch along with symptoms of systemic involvement (fatigue, weight loss, weakness). Dermoscopy revealing regular dilated parallel capillaries was suggestive of a benign/reactive vascular process. Histopathology in all three cases showed reactive vascular proliferation with a characteristic 90° branching. To date only 20 cases of adenopathy and extensive skin patch overlying plasmacytoma have been published, including ours. All patients presented with cutaneous lesions (violaceous patch and others) and most, at least 15/20, met the diagnostic criteria for polyneuropathy, organomegaly, endocrinopathy, monoclonal gammopathy, and skin changes. When clinical follow-up was reported, most patients had a favorable prognosis with partial or complete symptom resolution following treatment of the underlying plasmocytoma.