We report on a 52-year-old patient with an initial diagnosis of smoldering myeloma (SMM), who was monitored by means of dynamic and static positron emission tomography/computed tomography (PET/CT) with the radiotracer 1⁸F-fluorodeoxyglucose (18F-FDG). Baseline PET/CT revealed no pathological signs. Six months later, a transition to symptomatic, multiple myeloma (MM) was diagnosed. The transition was not accompanied by focal, hypermetabolic lesions on PET/CT. However, a diffusely increased 18F-FDG uptake in the bone marrow, accompanied by a marked increase of semi-quantitative (standardized uptake value, SUV) and quantitative, pharmacokinetic 18F-FDG parameters, was demonstrated. After successful treatment, including tandem autologous transplantation, the diffuse uptake in the bone marrow as well as the semi-quantitative and quantitative parameters showed a marked remission. This response was also confirmed by the clinical follow-up of the patient. These findings suggest that in MM a diffuse 18F-FDG uptake in the bone marrow may indeed reflect an actual bone marrow infiltration by plasma cells. Moreover, SUV values and kinetic parameters, not only from myeloma lesions but also from random bone marrow samples, may be used for MM monitoring. This could be particularly helpful in the follow-up of myeloma patients negative for 18F-FDG-avid focal lesions.

BACKGROUND: Scleredema is a rare sclerodermoid skin condition characterized by diffuse symmetrical thickening of the upper part of the body. Its association with monoclonal gammopathy and myeloma was recently described; very few cases have been reported to date.
METHODS: A 66-year-old Sri Lankan woman who had been followed in a dermatology unit for 34 years with diffuse systemic sclerosis presented with an acute exacerbation of the skin disease. Absence of Raynaud\'s phenomenon; sclerodactyly; characteristic lung, gastrointestinal, and cardiac involvement of systemic sclerosis; and repeatedly negative antinuclear antibodies test results led to reevaluation for the possibility of scleredema. Skin biopsies from four body sites showed normal epidermis and thickened reticular dermis with swollen collagen bundles separated from one another by clear spaces, resulting in fenestration. The skin appendages were not atrophied or bound down. Alcian blue staining showed interstitial mucin deposition. Serum protein electrophoresis demonstrated an abnormal monoclonal band in the β-region with a paraprotein level of 8.9 g/dl. Immunofixation showed an abnormal band in the γ-region consisting of immunoglobulin A and κ. Bone marrow biopsy revealed abnormal monoclonal plasma cells (15%) with multinuclearity. There was no evidence of end organ damage, and whole-body magnetic resonance imaging did not reveal any evidence of bone involvement. The patient\'s diagnosis was revised as scleredema type 2 associated with IgA-κ, and she was referred to a hemato-oncologist for chemotherapy, which led to significant improvement in the skin condition.
CONCLUSIONS: Scleredema is a rare disorder that has an enigmatic, rare association with monoclonal gammopathy. Dermatologists should be aware of this rare but important association.

Monoclonal gammopathies are characterized by serum monoclonal component (MC) plus an intact immunoglobulin and a free light chain (FLC), or a combination of both. The measurement of FLC with Freelite® is the standard practice recommended by International Myeloma Working Group guidelines. Recently, Hevylite® heavy/light chains (HLC) assays were introduced to specifically target junctional epitopes between the heavy and light chains of intact immunoglobulins, allowing the independent quantification of the involved (MC) and uninvolved (polyclonal immunoglobulin background) HLC isotype. Between January 2012 and March 2014, 90 patients were examined: 49 multiple myeloma (MM), 6 smoldering MM (SMM) and 35 monoclonal gammopathy of undetermined significance (MGUS). Of these 90 patients, 300 samples were collected at different times. The diagnostic and monitoring contribution of Hevylite A and G assays was assessed in all 90 patients examined. Additionally, 3 representative cases were selected. The Hevylite absolute values and ratio demonstrated high sensitivity and specificity with respect to serum protein electrophoresis and serum immunofixation. The combined use of Hevylite A and G with Freelite was particularly useful in dubious cases with more than one MC or with co-migrating components, as well as in the course of monitoring to assess the independent change of FLC and HLC, possibly reflecting the presence of clonal heterogeneity in the cohort. From this study, it can be concluded that FLC and HLC are independent, useful markers to monitor the MC and to assess with greater specificity and sensitivity the effect of therapy, thereby providing clinical support. Further studies are required to assess the prognostic potential of Hevylite in MGUS and SMM.