CASE REPORT Specific lymph node involvement in scleromyxedema: a new diagnostic entity for hypermetabolic lymphadenopathy Julie Delyon & Maud Bézier & Michel Rybojad & Josette Brière & Pierre Validire & Martine Bagot & Anne Janin & Maxime Battistella Received: 29 January 2013 / Revised: 29 April 2013 / Accepted: 5 May 2013 / Published online: 17 May 2013 # Springer-Verlag Berlin Heidelberg 2013 Abstract Scleromyxedema is a generalized skin disease mostly associated with monoclonal gammopathy. In its chronic course, it can lead to systemic disorders related to mucin deposits in organs. We describe here specific lymph node involvement, hitherto not reported in scleromyxedema. A 68-year-old man with a 1-year history of micropapular eruption and skin sclerosis involving the neck, trunk, hands, and face was diagnosed with scleromyxedema associated with IgG kappa monoclonal gammopathy. Enlarged mediastinal lymph nodes found on thoracic X-ray and computed tomography scan were hypermetabolic on positron emission tomography. Lymph node biopsy showed partial nodal infiltration by numerous fibroblasts surrounded by mucin and collagen deposits, the same being observed on the skin biopsy. Lymph node and skin lesions both improved after intravenous immunoglobulin and corticosteroid treatment. Lymph node involvement in scleromyxedema should be considered in the etiological diagnosis of hypermetabolic, enlarged lymph nodes, especially if monoclonal gammopathy is associated. Keywords Scleromyxedema . Lymph node . Monoclonal gammopathy . Mucinosis . PET–CT Introduction Scleromyxedema is a rare disease linked to dermal mucin deposits in the absence of thyroid disease. It is associated with fibroblast proliferation, fibrosis, and monoclonal gammopathy [1, 2]. In contrast to localized, purely cutaneous, lichen myxedematosus [3], it is a systemic disease that can involve the neurological, gastrointestinal, renal, ocular, cardiovascular, pulmonary, articular, and muscular systems [3–7], sometimes leading to severe complications. Lymph node involvement in scleromyxedema has not been reported so far. Monoclonal gammopathy in scleromyxedema is mostly of undetermined significance, since multiple myeloma is found in less than 10 % of cases [8, 9]. In other context, monoclonal gammopathy and enlarged hypermetabolic lymph nodes can suggest nodal lymphoma, especially B cell non-Hodgkin lymphomas [10]. We report herein a case of mediastinal adenitis with monoclonal gammopathy related to scleromyxedema, with specific lymph node involvement. Clinical history A 68-year-old man with a 1-year history of widespread papular eruption was referred to our institution. His medical history included prostatic adenoma treated with alpha- adrenergic blockers. Multiple papular lesions of 2–3 mm diameter, firm, closely spaced, and flesh-colored, involved the neck, upper back, inner thighs, retroauricular area, and J. Delyon : J. Brière : A. Janin : M. Battistella (*) Department of Pathology, AP-HP, Hôpital Saint-Louis, 1 avenue Claude Vellefaux, Paris 75010, France e-mail: maximebattistella@hotmail.com M. Bézier : M. Rybojad : M. Bagot Department of Dermatology, AP-HP, Hôpital Saint-Louis, Paris 75019, France J. Brière : M. Bagot : A. Janin : M. Battistella Université Paris Diderot, Sorbonne Paris Cité, 75010 Paris, France J. Brière : A. Janin : M. Battistella Inserm, U728, Paris 75010, France P. Validire Department of Pathology, Institut Mutualiste Montsouris, Paris, France Virchows Arch (2013) 462:679–683 DOI 10.1007/s00428-013-1424-2