Sporadic late onset nemaline myopathy and immunoglobulin deposition disease

Abstract

We speculate that deposition of light and heavy chains, rather than nemaline bodies, has myotoxic effects on skeletal muscle.

Rare myopathy associated to MGUS, causing heart failure and responding to chemotherapy

“…In most cases, nemaline myopathy is congenital, but recently, cases were described in adults and considered as "sporadic late onset nemaline myopathy" (SLONM). Associations of SLONM with MGUS were found not to be a coincidence [ 1 ]. In such cases, stem cell transplantation (SCT) demonstrated some efficacy [ 2 ], but such treatment was not considered at first for our patient, given his vulnerability.…”

Sporadic late-onset nemaline myopathy with monoclonal gammopathy of undetermined significance

“…Through our literature search in PubMed until April 2017, we identified 31 SLONM-MGUS patients in 19 articles [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22]. On review of the cases, the disease usually appears in their late 30s or older (the median of onset age is 47 years old [range: 27 -78]).…”

“…NB are visualized as fine cytoplasmic aggregates with dark to reddish purple color on the staining. On hematoxylin and eosin stain, NB seem mere basophilic areas and will be difficult to detect [8,11,12,15,22]. Observation of trichromatically stained frozen sections with higher magnification is recommended.…”

“…SLONM with HIV infection and that with neither MGUS or HIV appear to be heterogeneous, although SLONM with HIV infection is usually responsive to corticosteroid, intravenous immunoglobulin (IVIg), and plasmapheresis [24,25,27,30]. On the other hand, SLONM with MGUS (SLONM-MGUS) patients show a particular phenotype: severe weakness and atrophy in axial, limb-girdle, and occasionally distal muscles, dysphagia, and respiratory insufficiency, which are often refractory to immunotherapy [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22]. Of note, respiratory involvement is lethal, and the majority of the patients died within 1 to 5 years from the onset [8].…”

“…Subsequently, the efficacy of HDM-SCT or chemotherapy to the plasma cell dyscrasia has been demonstrated by other groups as well [13,15,[17][18][19]. Hence, today, regardless of rarity of the disease, the significance of early recognition of SLONM-MGUS is increasing since the disease is lethal but now can be considered treatable.…”