Sarcoidosis and Monoclonal Gammopathy of Undetermined Significance (MGUS): A True Association or Just a Coincidence?

Abstract

Sarcoidosis is a systemic inflammatory disease characterized by the presence of noncaseating granulomas in different organs. Sarcoidosis associated with monoclonal gammopathy of undetermined significance (MGUS) is a rare finding with only 10 cases reported to date. We describe a 79-year-old male patient who presented with dry mouth for 4 months. Lip biopsy done prior to admission showed nonnecrotizing epithelioid cell granulomas. On admission, laboratory analysis was significant for elevated calcium, decreased parathyroid hormone, increased erythrocyte sedimentation rate, undetectable parathyroid hormone-related peptide (PTHrp), mildly decreased 25-hydroxyvitamin D, elevated 1,25-dihydroxyvitamin D, elevated angiotensin converting enzyme, and positive Bence Jones protein in the urine. Serum protein electrophoresis showed an elevated gamma globulin level at 38% and an IgG monoclonal gammopathy with an M-spike of 1.47. Bone marrow biopsy was consistent with MGUS. The patient showed significant improvement with steroids and was discharged with close follow-up from nephrology and oncology. Salivary gland involvement in patients with sarcoidosis is a rare finding. Our case is a valuable addition to the small number of cases described in the literature supporting an association between plasma cell disorders and sarcoidosis. Larger prospective studies are needed to determine if a true association between the two diseases exists.

Co-occurrence of Three Systemic Diseases: ANCA-associated Vasculitis, Sjögren's syndrome and Sarcoidosis

“…For example, it has been reported that 11% of samples from patients with monoclonal gammopathy showed positive ANCA findings (19), while 6% of SjS patients were reported to have concomitant MGUS (20). Co-occurrence of sarcoidosis and MGUS has also been reported (21). Although there are no epidemiologic data to support the increased risk of MGUS in these systemic diseases, it has been suggested that dysregulation of the immune system may cause autonomous plasma cell clones and MGUS, while the dysregulation of cytokines, such as IL-1, IL-6, and TNF-α, may cause continuous stimulation of B cells (18).…”

A case of sarcoidosis with elevated serum IgM

“…The risk of progression of MGUS to multiple myeloma is approximately 1% per year [1]. Although MGUS or multiple myeloma in association with sarcoidosis is not well elucidated, 10 such cases were previously reported [2,3]. Additionally, 33 cases with both sarcoidosis and multiple myeloma were also reported [4].…”

“…As the one side of sarcoidosis, lymphoproliferative neoplasm is known to occur concomitantly with sarcoidosis [5]. One explanation for the relationship between sarcoidosis and MGUS is that the hypergammaglobulinemia induced by the chronic inflammatory response with sarcoidosis results in prolonged plasma cell lifespan [2][3][4]. Due to the risk of progression to multiple myeloma, a careful follow-up is required.…”

Sarcoidosis with Cardiac Involvement and Monoclonal Gammopathy

“…Саркоидоз, связанный с моноклональной гаммапатией неопределенного значения (MGUS), является редким обнаружением -описано только 10 случаев, о которых известно в настоящее время [16]. В 30 % случаев саркоидоз был первоначальным диагнозом, и в 30 % -MGUS была первоначальным диагнозом.…”

“…Имеется ли истинная ассоциация между заболеваниями плазматической клетки и саркоидозом или это совпадение, должны определить большие проспективные исследования [17]. Длительное наблюдение за этими пациентами и контроль клинического анализа крови, электрофореза белков сыворотки крови и уровня креатинина позволит установить истину [16].…”