Journal of Medical Cases, ISSN 1923-4155 print, 1923-4163 online, Open Access
Article copyright, the authors; Journal compilation copyright, J Med Cases and Elmer Press Inc
Journal website https://www.journalmc.org

Case Report

Volume 14, Number 2, February 2023, pages 64-70

Statin-Induced Immune-Mediated Necrotizing Myopathy Resulting in Proximal Muscle Weakness

Figures

Figure 1.
Figure 1. (a) Hematoxylin and eosin-stained section of muscle biopsy showing occasional regenerating and necrotic muscle fibers, with an associated sparse chronic lymphoid inflammation (arrow). No morphologic evidence of vasculitis is seen. No perifascicular atrophy is noted. (b) Esterase preparation darkly highlights macrophages (arrow) seen in association with necrotic myofibers. (c) NADH-TR preparation shows variable loss of the normal intermyofibrillar staining pattern in regenerating and necrotic muscle fibers. (d) No abnormal inclusions or rimmed vacuole type structures are noted on modified Gomori trichrome preparation. NADH-TR: nicotinamide adenine dinucleotide hydrogen-TR stain.
Figure 2.
Figure 2. (a) Hematoxylin and eosin (H&E)-stained section of muscle biopsy demonstrates the presence of scattered regenerating and necrotic muscle fibers with only very sparse focal chronic lymphoid inflammation (arrow) (“necrotizing myopathy”). (b) MHC1 staining showing patchy mild to moderate increase in membranous muscle fiber staining for MHC1 (arrow). (c) Esterase preparation darkly highlights scattered acutely angulated atrophic muscle fibers (arrow), and highlights macrophages seen in association with necrotic muscle fibers (arrowhead). (d) NADH-TR preparation demonstrates variable loss of the normal intermyofibrillar staining pattern in regenerating and necrotic muscle fibers. NADH-TR: nicotinamide adenine dinucleotide hydrogen-TR stain; MHC: major histocompatibility complex.

Tables

Table 1. Myositis Extended Panel for Case 1
 
Myositis extended panelResultsReference values
IgG: immunoglobulin G; SSA 52 RO ENA Ab IgG: SSA 52 RO extractable nuclear antigen antibodies; SSA 60 RO ENA Ab IgG: SSA 60 RO extractable nuclear antigen antibodies; Ribo Prot U1 ENA Ab, IgG: anti-ribonucleoprotein U1 extractable nuclear antigen antibodies; Jo-1 Hist.-tRNA Syn. Ab, IgG: Jo-1 histidyl-tRNA synthetase antibodies; PL-7 (threo.-tRNA syn.) Ab: anti-threonyl-tRNA synthetase antibodies; PL-12 (alanyl-tRNA syn.) Ab: anti-alanyl-transfer RNA synthetase antibodies; EJ (glycyl-tRNA syn.) Ab: EJ (glycyl-tRNA synthetase) antibody; SRP (signal Rec. Part.) Ab: SRP (signal recognition particle) antibody; OJ (isoleucyl-tRNA syn.) Ab: OJ (isoleucyl-tRNA synthetase) antibody; MDA5 (CADM-140) Ab: melanoma differentiation-associated gene 5 antibody; TIF-1 gamma (155 kDa) Ab: anti-transcription intermediary factor 1 (TIF1)-γ autoantibodies; Fibrillarin (U3 RNP) Ab, IgG: fibrillarin (U3 ribonucleoprotein) antibody.
SSA 52 RO ENA Ab IgG00 - 40 AU/mL
SSA 60 RO ENA Ab IgG00 - 40 AU/mL
Ribo Prot U1 ENA Ab, IgG20 - 19 U
Jo-1 Hist.-tRNA Syn. Ab, IgG00 - 40 AU/mL
Mi-2 (nuc. heli. Prot.) AbNegativeNegative
PL-7 (threo.-tRNA syn.) AbNegativeNegative
PL-12 (alanyl-tRNA syn.) AbNegativeNegative
P155/140 (FIF1-gamma) AbNegativeNegative
Ku antibodyNegativeNegative
EJ (glycyl-tRNA syn.) AbNegativeNegative
SRP (signal Rec. Part.) AbNegativeNegative
OJ (isoleucyl-tRNA syn.) AbNegativeNegative
SAE1 (SUMO activating enzyme) AbNegativeNegative
NXP-2 (nuclear matrix protein-2) AbNegativeNegative
MDA5 (CADM-140) AbNegativeNegative
TIF-1 gamma (155 kDa) AbNegativeNegative
PM/Scl 100 Ab, IgGNegativeNegative
Fibrillarin (U3 RNP) Ab, IgGNegativeNegative

 

Table 2. Myositis Extended Panel for Case 2
 
Myositis extended panelResultsReference values
IgG: immunoglobulin G; SSA 52 RO ENA Ab IgG: SSA 52 RO extractable nuclear antigen antibodies; SSA 60 RO ENA Ab IgG: SSA 60 RO extractable nuclear antigen antibodies; Ribo Prot U1 ENA Ab, IgG: anti-ribonucleoprotein U1 extractable nuclear antigen antibodies; Jo-1 Hist.-tRNA Syn. Ab, IgG: Jo-1 histidyl- tRNA synthetase antibodies; PL-7 (threo.-tRNA syn.) Ab: anti-threonyl-tRNA synthetase antibodies; PL-12 (alanyl-tRNA syn.) Ab: anti-alanyl-transfer RNA synthetase antibodies; EJ (glycyl-tRNA syn.) Ab: EJ (glycyl-tRNA synthetase) antibody; SRP (signal Rec. Part.) Ab: SRP (signal recognition particle) antibody; OJ (isoleucyl-tRNA syn.) Ab: OJ (isoleucyl-tRNA synthetase) antibody; MDA5 (CADM-140) Ab: melanoma differentiation-associated gene 5 antibody; TIF-1 gamma (155 kDa) Ab: anti-transcription intermediary factor 1 (TIF1)-γ autoantibodies; Fibrillarin (U3 RNP) Ab, IgG: fibrillarin (U3 ribonucleoprotein) antibody.
SSA 52 RO ENA Ab IgG10 - 40 AU/mL
SSA 60 RO ENA Ab IgG00 - 40 AU/mL
Ribo Prot U1 ENA Ab, IgG10 - 19 U
Jo-1 Hist.-tRNA Syn. Ab, IgG00 - 40 AU/mL
Mi-2 (nuc. heli. Prot.) AbNegativeNegative
PL-7 (threo.-tRNA syn.) AbNegativeNegative
PL-12 (alanyl-tRNA syn.) AbNegativeNegative
P155/140 (FIF1-gamma) AbNegativeNegative
Ku antibodyNegativeNegative
EJ (glycyl-tRNA syn.) AbNegativeNegative
SRP (Signal Rec. Part.) AbNegativeNegative
OJ (isoleucyl-tRNA syn.) AbNegativeNegative
SAE1 (SUMO activating enzyme) AbNegativeNegative
NXP-2 (nuclear matrix protein-2) AbNegativeNegative
MDA5 (CADM-140) AbNegativeNegative
TIF-1 gamma (155 kDa) AbNegativeNegative
PM/Scl 100 Ab, IgGNegativeNegative
Fibrillarin (U3 RNP) Ab, IgGNegativeNegative