Table 1.

Pathologic Findings Identified in Archived CQ- or HCQ-Induced Myopathies

Case	CQ/HCQ Use	Specimen	Light Microscopic Findings	Special Stains	Electron Microscopic Findings
1 (index case)	HCQ, >20 y	Cardiac biopsy	Vacuolar myopathy	Congo red, negative	Myeloid and curvilinear bodies
2	HCQ, 9-11 y	Cardiac biopsy	Vacuolar myopathy Mild to moderate myocyte hypertrophy and minimal interstitial fibrosis	Congo red, negative	Abnormal lysosomal debris with whorled lamellar structure (myeloid body), debris is also associated with cytoplasmic glycogen Curvilinear inclusions Hypercontraction changes Lipofuscin deposits
3	HCQ, duration unknown	Right thigh muscle biopsy	Vacuolar myopathy	None performed	Lysosomal membranous debris Membrane-bound glycogen
4	HCQ, duration unknown	Quadriceps biopsy	Vacuolar myopathy	Trichrome: Increased granular staining Diffusely increased acid phosphatase reactivity	Myeloid bodies
5	HCQ, 6 y	Left vastus lateralis Left deltoid	Vacuolar myopathy Focal perimysial mononuclear inflammatory cell infiltrates	Not performed	Myeloid and curvilinear bodies

CQ, chloroquine; HCQ, hydroxychloroquine.