Monoclonal gammopathies of uncertain significance (MGUS) correspond to pre-malignant hematological disorders characterized by the production of a monoclonal protein and infiltration of less than 10% of the bone marrow by plasma cells. Its importance lies in the risk of progression to malignant disorders and in the association with different renal, neurological and skin manifestations. There are pathophysiological mechanisms that support a causal relationship between monoclonal gammopathies (MGs) and different skin diseases, such as type I cryoglobulinemia (CG), primary systemic amyloidosis (PSA) or necrobiotic xanthogranuloma (NXG). However, there is a group of skin diseases associated with MGs whose pathogenesis has not been elucidated. In this context, the role of the dermatologist is crucial in the suspicion of different haematological disorders based on skin manifestations and in the multidisciplinary treatment of these patients. In this article, we carry out an exhaustive review of the literature published in this area and propose a screening algorithm for MGs in patients with specific skin diseases.

Background: One of the devastating consequences of monoclonal gammopathies is the development of end-stage kidney disease, which can be prevented with an early diagnosis. Renal involvement can be secondary to saturation of paraproteins with intratubular precipitation or the glomerular deposition of paraproteins with secondary inflammation and destruction. These conditions can also be associated with monoclonal gammopathies that do not meet hematological treatment criteria, called monoclonal gammopathies of renal significance (MGRS). Aim: To report a retrospective analysis of patients who underwent a renal biopsy and whose final diagnosis was a form of monoclonal gammopathy. Material and Methods: We reviewed the clinical and laboratory features and response to treatment of 22 patients aged 63 ± 12 years (55% women) with a pathological diagnosis of a nephropathy associated with paraproteinemia. Results: The most common hematological diagnosis was amyloidosis in 50% of patients, followed by cast nephropathy. The predominant clinical presentations were proteinuria (without nephrotic syndrome) and nephritic syndrome. Classic criteria such as erythrocyte sedimentation rate > 100 mm/h and protein-albumin gap were unusual. Serum light chain quantification was the test with the best yield to detect paraproteins. Conclusions: In this group of patients, light chains tend to affect the kidney more commonly than heavy chains. The prognosis of multiple myeloma is much worse than MGRS.

ABSTRACT Objective We aimed to describe the presentation of papillary microcarcinoma (PTMC) and identify the clinical and histological features associated with persistence/recurrence in a Latin American cohort. Subjects and methods Retrospective study of PTMC patients who underwent total thyroidectomy, with or without radioactive iodine (RAI), and who were followed for at least 2 years. Risk of recurrence was estimated with ATA 2009 and 2015 classifications, and risk of mortality with 7th and 8th AJCC/TNM systems. Clinical data obtained during follow-up were used to detect structural and biochemical persistence/recurrence. Results We included 209 patients, predominantly female (90%), 44.5 ± 12.6 years old, 183 (88%) received RAI (90.4 ± 44.2 mCi), followed-up for a median of 4.4 years (range 2.0–7.8). The 7th and 8th AJCC/TNM system classified 89% and 95.2% of the patients as stage I, respectively. ATA 2009 and ATA 2015 classified 70.8% and 78.5% of the patients as low risk, respectively. Fifteen (7%) patients had persistence/recurrence during follow-up. In multivariate analysis, only lymph node metastasis was associated with persistence/recurrence (coefficient beta 4.0, p = 0.016; 95% CI 1.3-12.9). There were no PTMC related deaths. Conclusions Our series found no mortality and low rate of persistence/recurrence associated with PTMC. Lymph node metastasis was the only feature associated with recurrence in multivariate analysis. The updated ATA 2015 and 8th AJCC/TNM systems classified more PTMCs than previous classifications as low risk of recurrence and mortality, respectively.