Lichen myxedematosus (LM) is an idiopathic cutaneous mucinosis disorder, and monoclonal gammopathy of undetermined significance (MGUS) is a preneoplastic plasma cell disease with a monoclonal increase in globulin. Patients with LM combined with monoclonal gammopathy are normally diagnosed with scleromyxedema. However, we report a case of generalized papules combined with MGUS in a 78-year-old man who was eventually diagnosed with atypical or intermediate forms of LM because it only involved the skin, and the pathological type was not consistent with scleromyxedema. Few cases of atypical or intermediate forms of LM have been reported, so the course of atypical or intermediate forms of LM is unpredictable. We report the diagnosis and treatment of a case of atypical forms of LM to discuss the current understanding of the disease, hoping to provide a reference for clinical research on this disease.

UNASSIGNED: Light-chain deposition disease (LCDD) is a systemic disorder characterized by non-amyloidotic light-chain deposition in various organs with Bence-Jones type monoclonal gammopathy. Although known as monoclonal gammopathy of renal significance, it may involve interstitial tissue of various organs, and in rare cases, proceeds to organ failure. We present a case of cardiac LCDD in a patient initially suspected of dialysis-associated cardiomyopathy.
UNASSIGNED: A 65-year-old man with end-stage renal disease requiring haemodialysis presented with fatigue, anorexia, and shortness of breath. He had a history of recurrent congestive heart failure and Bence-Jones type monoclonal gammopathy. A cardiac biopsy performed for suspected light-chain cardiac amyloidosis was negative for diagnostic Congo-red stain, however, paraffin immunofluorescence examination for light-chain suggested diagnosis of cardiac LCDD.
UNASSIGNED: Cardiac LCDD may go undetected leading to heart failure due to lack of clinical awareness and insufficient pathological investigation. In heart failure cases with Bence-Jones type monoclonal gammopathy, clinicians should consider not only amyloidosis but also interstitial light-chain deposition. In addition, in patients with chronic kidney disease of unknown cause, investigation is recommended to rule out cardiac light-chain deposition disease concomitant with renal LCDD. Although LCDD is relatively rare it occasionally affects multiple organs; therefore, it would be better to describe it as a monoclonal gammopathy of clinical significance rather than one of renal significance.

Plasma cell dyscrasias (PCD) are characterized by an abnormal production of intact monoclonal immunoglobulins or parts such as heavy or light chains. In most cases, the monoclonal protein (also termed paraprotein) is produced by a clonal plasma cell population. The production of monoclonal proteins can result in deposits of various types and localization depending on the type, amount, and electrochemical properties of the paraprotein. One histopathologic presentation, albeit rare, are crystalline deposits. They can form in various organs and hence cause a wide spectrum of symptoms.
A 49-year-old man presented to the emergency department with eyestrain and foreign body sensation after overhead drilling. Examination of the eyes revealed crystalline deposits in the cornea of both eyes. After additional diagnostic testing, deposits were attributed to free light chains. Monoclonal gammopathy of undetermined significance (MGUS) was diagnosed according to serum electrophoresis and immunofixation. Four years later, new onset of proteinuria was detected. A percutaneous biopsy of the kidney showed severe light chain podocytopathy with secondary focal segmental glomerulosclerosis (FSGS) and light chain proximal tubulopathy (LCPT). In these lesions, crystalline deposits identical to the corneal deposits were found in ultrastructural and immunofluorescent analysis. The patient was diagnosed with monoclonal gammopathy of renal significance (MGRS), and a plasma cell directed therapy was initiated.
PCD can present with a wide array of symptoms and are notoriously difficult to diagnose. Extrarenal manifestations such as crystalline deposits in the cornea are one possible manifestation. The case presented herein emphasizes the notion that extrarenal paraprotein deposits warrant a thorough search for the underlying clonal disease.