pathology

1. Muscle biopsy & interpretationMuscle biopsy & interpretation
Dr. Rashmi Gujarathi

2. IndexIndex
 Structure & histology of muscle
 Types of muscles
 Indications & Contraindications of muscle Bx
 Procedure & Practical aspects of muscle Bx
 Sample preparation & Staining
 General abnormalities seen in response to
injury.
 Neuromuscular diseases
 Biochemical investigations

3. Normal structure & histology of muscleNormal structure & histology of muscle

4. Types of muscle fibresTypes of muscle fibres
Type - 1 Type -2
Red /oxidative/slow glycolytic/fast/white
o ATPase Low High
 Oxidative High Low
enzyme cont.
 Glycogen Low High
 Phosphorylase Low High
 Lipid cont. High Low

5. Types of muscle fibresTypes of muscle fibres
Type - 1 Type -2
Inc.Myoglobin. Dec myoglobin
 Postural activity Sudden
intermittent activity
 Aerobic Anareobic
 35- 40% 60-65%

6. Diff. Between These types done byDiff. Between These types done by
histochemical stain on frozen sectionhistochemical stain on frozen section
Type-1 Type-2A Type 2B
1)ATPase reaction Light Dark Intermediate
at 9.4 pH
2)ATPase reaction Dark Light Intermediate
At acidic pH
3)NADH-TR reac. Dark Intermediate Light
Depend on conc.of
mitochondria
4)Antibodies
Slow +nt -nt -nt
Fast - nt +nt +nt

7. Normal histochemistry of MuscleNormal histochemistry of Muscle
NADH-TR
II
I

8. Muscle Biopsy - IntroductionMuscle Biopsy - Introduction
 Introduced by Duchenne – 1868
 Simple but invasive procedure
 Interpretation requires detailed clinical history ,
physical examination, biochemical studies.

9. Indications of Muscle Bx –Indications of Muscle Bx –
Kakulas &Adams- 1985Kakulas &Adams- 1985
 Investigation of muscle weakness, static &
progressive
 To diff bet. myogenic /neurogenic cause of
weakness.
 Patients suspected of having inflammatory
myopathy & collagen vascular diseases
 Metabolic diseases where muscle is likely to
be affected.

10. Indications of Muscle Bx –Indications of Muscle Bx –
Kakulas &Adams- 1985Kakulas &Adams- 1985
 Suspected drug induced myopathy.
 In asymptomatic carrier of genetic diseases.
 To access the disease progress and
prognosis
 For research

11. Diseases ass. with weakness in whichDiseases ass. with weakness in which
muscle Bx is low-yieldmuscle Bx is low-yield
 Electrolyte disturbances
 Endocrine diseases
 Malignant hyperthermia
 Myasthenic syndromes
 Old age
 Periodic paralysis
 Poor nutrition

12. Muscle Bx - TechniqueMuscle Bx - Technique
Selection of Muscle :
1) Moderately affected or muscle in which disease is
evolving should be selected.
2) Ideal site- Quadriceps / deltoid /biceps.
3) Bx should be taken from belly of muscle, away from
tendinous insertion.
4) In autopsy cases, Bx can be taken upto 12 hrs.
Avoid-
1) Severely / minimally affected muscle
2) Previously injured site- by EMG, intramuscular
injection
3) If rhabdomyolysis occurred, 3 mths back.

13. ProcedureProcedure
1) Open Bx
2) Needle Bx
Open Bx –
 Use for diseases with patchy involvement e.g PM
 Is obtained through a skin incision under local
anesthesia
 Infiltration of local anaesthesia into muscle is avoided.
 Avoid use of dithermy , cautery.

14. ProcedureProcedure
Needle biopsy
 Less traumatic , simple
Uses-
 Particularly for biochemical investigation and
 Follow up Bx to monitor the progress of treatment.
Disadvantage:
 Small size of Bx
 Difficulty in orientation of tissue.

15. ProcedureProcedure
 Muscle is maintained in isometric state by using
muscle clamp in situ
e.g Price muscle clamp
Wooden swab stick
 Use- to prevent contraction artefact
Orientation of specimen

16. ProcedureProcedure
 Fresh specimen for histochemistry & fixed specimen for
LM & EM
 3rd
specimen is taken if required for biochemical analysis
& genetic analysis
 Size of specimen should be 1x0.5xo.5 cm.
2 pieces of muscle should be taken

17. ProcedureProcedure
Precautions:
 Do not crush the muscle.
 Do not stretch the muscle.
 Do not tie any stick.
 Do not put directly into ice ( to prevent freezing
artefact)
 Do not directly immerse in saline
Transportation
 Moisten the specimen with saline dampened gauze
and send it to laboratory.
 If sent in a flask containing ice cubes , this can be
delayed for up to 4-6 hrs.

18. Processing of fresh sampleProcessing of fresh sample
 Flash freezing by isopentane cooled in
liquid nitrogen at –160 deg C
 Frozen cryostat section of 10 micron are cut
at –18 to – 20 deg C

19. Various stain used areVarious stain used are
 Congo red Detection of amyloid
deposition
 Myophosphorylase McArdle’s disease
 PFK PFK deficiency
 Myoadenylate Myoadenylate deaminase
deaminase deficiency
 Dystrophin DMD & BMD
immunostain
 Dysferin immunostain LGMD 2B
 Membrane attack Dermatomyositis
complex immunostain

20. Processing of fixed specimenProcessing of fixed specimen
 Clamped specimen fixed in
10 % buffered neutral formalin – LM
3% glutaraaldehyde – EM ( sp. Size0.5x 0.5 x 0.2
mm)
 2 sections are taken - longitudinal
- Transverse
 Each of 6 micron thick
 Stains used – H&E, Retic ,Trichrome, PAS

21. Abnormalities seen on Paraffin /Abnormalities seen on Paraffin /
frozen sectionsfrozen sections
Paraffin section
 Nuclear changes
 Fiber regeneration
 Fiber necrosis
 Hyaline fibers
 Inflammation
 Ring fibers
 Fibrosis & fatty
infiltration
Frozen section
 Fiber shape
 Changes in
histochemical profile
 Fiber spiltting
 Mottled fibers
 Cores & targets
 Nemaline rods
 Mitochondrial
abnormalities
 Vacuolar change

22. General abnormalities of muscleGeneral abnormalities of muscle
in response to injuryin response to injury

23. Nuclear changesNuclear changes
 Normal nuclei- peripheral
 Large no. of myofibres with central / paracentral
nuclei - s/o Myopathic diseases.
 Increase in internal nuclei –MC abnormality

24. Nuclear changesNuclear changes
Internal nuclei are seen in:-
 Myotendinous insertion
 Fibre atrophy - multiple pyknotic
nuclei forming clusters.
 Fibre regeneration – vesicular
nuclei with prominent nucleoli.
 Centronuclear myopathy- Single
central/ paracentral nucleus in
almost all fibers-
 Myotonic dystrophy- randomly
distributed nuclei with active
appearing nuclei (dispersed
chromatin)

25. Hyaline fibres ( Degeneration)Hyaline fibres ( Degeneration)
Degenerating rounded and enlarged
More deeply stained than normal
Sarcoplasm – smudged, homogenous
Nuclei – Pyknotic in centre / periphery
DMD- Large no. of Hyaline fibres

26. Fibre necrosisFibre necrosis
Presence of degeneration & necrosis – definite sign of
myopathy
Best seen in H&E section
Loss of striation
Swelling of myofober eosinophilia
(acute necrotic fibers)
Later pale color
Sarcoplasm striated to coarsely granular
Nucleus –Pyknotic,fragmented ,absent
Macrophage seen in surrounding
fibres

27. Fibre NercosisFibre Nercosis
Necrosis seen in:
 Small groups of necrotic fibre - DMD
 Perifascicular necrosis - DM
 Random fibre necrosis - PM,IBM
 Infarcts & large areas of necrosis - PAN
 Extensive, diffuse necrosis -
Rhabdmyolysis, in patient with canitine pamitoyl
transferase deficiency, alcoholics, military recruits.

28. Fibre regenerationFibre regeneration
Degeneration/ Necrosis
Compensatory regeneration
Increased basophilia
Source of regeneration:
1.Sprouts of remaining
sarcoplasm
2.Satellite cells – more
capacity to regenerate.
Regenerating fibres – increased basophilia
Nuclei increased in number, larger than normal
With vesicular chromatin, prominent nuclei.

29. Fibre splittingFibre splitting
 Hypertrophic fibres split into 2/>2 subunits.
 A spilt like space from invagination individual
segment.
 -Limb girdle dystrophy
 -IBM
 Mechanism- (A form of
Regeneration)-failure
to unite to form a
single fibre

30. AtrophyAtrophy
 MC histological change
 Interpretation better in cross section & in frozen
section.
General causes of atrophy( non selective )-
1. Denervation- MC
2. Disuse
3. Ischemia
4. Aging
5. Poor nutrition.

31. Selective atrophySelective atrophy
Type 1 atrophy
 Myotonic dystrophy
 Nemaline myopathy
 Distal myopathy
 Centronuclear
myopathy
 Congenital fiber type
disproportion.
Type 2 atrophy
 Corticosteroid therapy
 MG
 Disuse atrophy
 Acute denervation
 Paraneoplatic
myopathy.

32. Morphometric analysis of atrophyMorphometric analysis of atrophy
 Done either manually / computer assisted image
analyzer.
 Lesser diameter of each muscle fiber should be
measured.
 At least 200 fibers should be present in the sample.
Interpretation:
 Grouped atrophy- 5/>5 angular fibers –
pathognomonic for chronic neurogenic disease
 Panfascicular Atrophy – ISMA
 Perifascicular atropy – DM
 Atrophic fibers randomly situated in the section is
non specific.

33. Fiber hypertrophyFiber hypertrophy
 Type 1:
 ISMA
 Type 2:
 Runners sprinters
 Congenital fiber type
disproportion
•Limb – girdle
dystrophy
IBM
Myotonia
congenital
Acromegaly

34. Changes in histochemical profile:Changes in histochemical profile:
Denervation
Renervation of different Nv.
Causes change in muscle
Loss of checkerboard type
pattern - Type grouping
Motor unit

35. Type groupingType grouping
ATPase
I
II

36. InflammationInflammation
PM
1)Inflammatory myopathies-PM, DM &
IBM
2)Immunologically mediated
myopathies SLE & RA.
PM –
1.Inflammatory cells invade the
endomysium, enveloping necrotic
fibres.
2. Sheets of inflamm. cells expand
endomysial spaces in acute severe
disease.

37. InflammationInflammation
 DM – Infiltration of vascular walls by mononuclear
cells.
 RA :Nodular infiltration of plasma cells
PAN – affinity for large vessels – arteries within
epimysium and perimysium.
Entire wall shows infiltration
by inflammatory cells
including eosinophils.
DM

38.  SLE- Small vessels are
affected
Fibrinoid necrosis present with
neutrophils
 Granulomatous inflammation:
1. Sarcoidosis-non necrotizing
granulomas
2. Idiopathic granulomatous
myositis. – Chronic
progressive myopathy of
middle aged person.
InflammationInflammation

39. Core & TargetsCore & Targets
Better seen in oxidative enzyme stain
Targets -
Appear as central pallor s/by darkly stained rim, in turn s/by
normal appearing area.
Cores-
Appear as a central pallor s/by normal appearing area
without dark zone.
Target Cores
Central -pale
area: -nce of
oxidative
enzyme
Central-amorphous
electron dense material
Intermed-Mitochondria
Outer- normal

40. Core & TargetsCore & Targets
Target Cores
Always single Single/multiple &
eccentric
Extends upto few sarcomere Extends throughout
the length
>diameter. <diameter
Pathognomonic for Neurogenic Central core disease
atrophy

41. Ring fibresRing fibres
F
Formed by peripheral bundle of myofibril.
Directed circumferentially, encircling inner portion of
myofibre.
Seen in transverse section.
Striation are visible under PAS, Resin & EM
Normally seen in extraocular muscles.
Seen in LGD & MD
Large no. of ring fibres – S/O MD

42. Mitochondrial ABNRMitochondrial ABNR
Ragged Red fibres
 Normally- mitochondria scattered within
sarcoplasm.
 Redistribution of mitochondria beneath
sarcolemma-forming aggregates.
 Aggregates app as red with trichrome.
 Margins of involved fibres- irregular, ragged
appearance
 EM- enlarged, deformed
mitochondria due to inclusion
of creatine kinase.

43. Mottled fibersMottled fibers
 Seen in oxidative preparations NADHTR
 Seen as unevenly staining fibres.
 D/t minute, irregular zones of weak enzyme
activity- scattered in sarcoplasm.
 Mechanism- Lack of mitochondria &
destruction of myofibrils.
 Fascioscapular and limb girdle dystrophy.

44. Vacuolar changeVacuolar change
In the center arranged in size
gradient
Subsarcolemmal PAS +ve.
In scattered fibers, small,
round, osmiophilic, ORO
+ve
Rimmed ubiquitin +ve
Diseases
Freezing artifact
Glycogen Storage dis., Lipid
storage disease
Mitochondrial myopathy.
IBM, distal myopathy, OPD
Sarcoplasmic vacuoles
Rimmed Vacuole – sharply demarcated vacuole
containing granular material that forms red rim in frozen
section. Supposed to be autophagic vacuole – membrane
bound.

45. Nemaline rodsNemaline rods
 Nemaline – thread like
 Seen as clusters of threads
beneath sarcolemma.
 Rods are osmiophilic
oblong structures of 6-7
micrometer.
 Resembling Z band
 Seen in nemaline myopathy
– congenital nonprogresive
muscle dis. of childhood
Trichrome

46. Fibrosis and Fatty InfiltrationFibrosis and Fatty Infiltration
 End stage disease :
 Previous Angiocentric – DM, Connective
tissue disease, FSHD
 Endomysial around fibres – PM, IBM, Viral
myositis

47. WorkingWorking Classification of neuromuscularClassification of neuromuscular
diseasesdiseases
Neurogenic atrophy
Neuromuscular Junction disorders
Primary myopathic diseases
- Inflammatory myopathies
- Non inflammatory myopathies
1) Muscular dystrophies
2) Developmental disorders of skeletal muscle
3) Myofibrillary myopathies
4) Metabolic myopathies
5) Toxic & Drug induced myopathies

48. Neurogenic atrophyNeurogenic atrophy
Diseases affecting lower motor neurons or
their axons are-
-Amyotrophic lateral sclerosis in adults
-Spinal muscular atrophy usually in children
-Poliomyelitis - now rare
-Peripheral neuropathy of various types

49. Histological changesHistological changes
Denervation
randomly scattered atrophic fibers
Predominantly atrophy of type 2 fibers.
smaller and more angular, (Round in childhood
spinal muscular atrophy)
atrophy of adjacent
motor units groups of fibers
Group atrophy.

50. Histological changesHistological changes
Denervated muscle fibers
Reinnervated by collateral sprouting. ,
all of the reinnervated fibers are converted
to a single histochemical fiber type
loss of the normal checkerboard pattern
”Type grouping."

51. NADH-TR stain-
Reinnervation
Target fiber-central pallor with darkly stained rim
MC in polyneuropathies,
Long standing denerveation
Hypertropyhy/ fiber splitting
& Small atrophic fibers
Fibroadipose tissue
Histological changes

52. Inflammatory / immune mediatedInflammatory / immune mediated
myopathymyopathy
 Polymyositis
 Dermatomyositis
 Inclusion body myositis
 Viral myositis-Influenza, Cox-sackie A & B
 Pyomyositis -Drug addicts and immunocompromised
 Granulomatous inflammation -TB & sarcoidosis
 Parasitic infestation-Trichinella & cysticercosis

53. Inflammatory / immune mediatedInflammatory / immune mediated
myopathymyopathyPM
 Insidious onset
 Affects females 20-40 yrs.
 S/S-Symmetrical proximal muscle weakness, -
Abrupt in onset, rapidly progressive period of
 Increased ESR, CPK.
 Cell-mediated autoimmune disorder in which
cytotoxic T-cells and macrophages invade and
destroy myofibers.

54. Histological featuresHistological features
•Myonecrosis
•Intrafascicular- endomysial
mononuclear cells infiltration of T
cells surrounding non-necrotic
fibres.
•Early phase- necrotic fibers-
hypereosinophilic, granular,
nuclear pyknosis
•Pale vacuolated fibers with
myophagocytosis.

55. DermatomyositisDermatomyositis
 Present as Adult & Juvenile form
 Purple (heliotrope) discolorarion of the
upper eyelids
 Dusky red patches over extensor surfaces
of the extremities
 B/L symmeterical proximal weakness , slow
in onset.
 Extramuscular manifestations frequent in
children.
Asso. With Ca lung ,colon & breast

56. DermatomyositisDermatomyositis
 Circulating anti-endothelial antibodies.
Activation of complement,
Endothelial swelling/ necrosis capillary loss
Ischemic infarction
Myofiber necrosis
Histology-
 Inflammation around
endomysial and perimysial
capillaries and arterioles.
 perifascicular atrophy

57. DermatomyositisDermatomyositis
H & E

58. IBMIBM
 50 -70yrs
 M > F
 nonresponsive to steriod
 Asymetrical weakness of acral muscle esp. in extensor
compartment of arm
 S/o viral origin

59. IBMIBM
 Small group atrophy with angular fibres
Hypertrophic & split fibres
 Endomysial chronic inflammatory infiltrate
 Rimmed vacuoles- slit like vacuoles in
cytoplasm surrounded by haematoxyphilic
granules
 inclusion bodies in vacuoles
 Inclusions contain beta amyloid,
hyperphosphorylated tau protein,
apolipoprotein E

60. IBMIBM
Rimmed
vacuoles
H & E
Resin

61. Muscular dystrophiesMuscular dystrophies
 Duchenne muscular dystrophy
 Becker’s muscular dystrophy
 Limb girdle muscular dystrophy
 Fascioscapulohumeral dystrophy
 Myotonic dystrophy
 Distal myopathy
 Oculopharyngeal muscular dystrophy

62. Duchene muscular dystrophyDuchene muscular dystrophy
 MC muscular
dystrophy
 XR
 Age- 2-4 yrs
 Exclusively male
 Genetics- Def. Of
dystrophin
 Gene for dystrophin
located on Xp21

63. Duchene muscular dystrophyDuchene muscular dystrophy
 C/F -Difficulty in running , jumping getting
up steps
 Proximal > distal & LL> UL
 Weakness of pelvifemoral &
scapulohumeral muscles, cardiac muscle
 Pseudohypertrophy of quadriceps gluteal
deltoid
 Cardiac involvement +nt

64. Duchene muscular dystrophyDuchene muscular dystrophyBx-
 Excessive variation in size shape of fibers
 Large rounded fibers with small atrophic fibers
 Inc. hyaline fibers
 Necrosis & phagocytosis in both fibers type with
small basophilic regeneration fibers.
 Patchy endomysial fibrosis
 Fiber splitting is seen in
 Hypertrophic fibers

65. DMD

66. IHCIHC
normal DMD
Dystrophin in normal & in DMD

67. Becker’s MDBecker’s MD
X- linked
Less severe than DMD
Late onset
Pathogenesis – contains dystrophin in
normal amt. but ABNR structure/ size.
C/F -Pelvic girdle & thigh muscles
involved first

68. Becker’s MDBecker’s MD
Microscopy
Endomysial fibrosis
Scattered large hypercontracted
Fibers of variable size with necrosis &
regeneration
ATPase

69. FSHDFSHD
 AD
 3-4 th
decade
 Involves voluntary muscles of face shoulder's , UL
 Bx –
- Atrophic fibers in absence of necrosis/ regeneration.
- Numerous moth eaten fibers
- Perivascular Lymphocytes +nt in early stages.

70. Limb girdle dystrophyLimb girdle dystrophy
 AR
 Young adult
 Sarcoglycan deficiency – 17q12 (4types)
 Consists of myopathies involving proximal axial muscles.
 Gradual onset, progressive weakness
 Bx-
 Marked nuclear internalization variability in fiber size.
 Hypertrophic fibres with fiber splitting.

71. Myotonic DystrophyMyotonic Dystrophy
Myotonia—Failure to relax after contraction d/t
membrane defect.
AD
Defective gene – 50/>50 repeats of CTG
trinucleotide
Two forms- Congenital & adult form.
Muscles of face, jaw & eyelids-involved.
Ptosis, expression less face, dysphagia
Myotonia present in earlier stages
Other manifestation – cataract, COM, Mild
Dementia, DM, testicular Atrophy.

72. Myotonic DystrophyMyotonic Dystrophy
Bx
 Multiple pyknotic internal nuclei
 Selective atrophy of type 1 fibers
 Type II hypertrophy
 Ring fibers & sarcoplasmic masses
 In chronic cond.– fibrosis, degeneration,
regeneration, fibrosis.

73. Distal myopathyDistal myopathy
1.Welander myopathy
2.Miyoshi myopathy
3.Hereditary variant of IBM
4.Non Scandinavian myopathy
 Bx –
-Abnormal no. of internalized nuclei
-Variable fiber diameters
-Selective atrophy at type 1- Welander
-Rimmed vacuoles in non Scadinavian myopathies.

74. OPMDOPMD
 Late onset myopathy
 Ptosis, Opthalmoplegia & dysphagia
 Benign course.
 Bx- -
-Mild dystrophic change with internalization of nuclei.
-Fiber atrophy.
-Interstitial fibrosis
-Sometimes rimmed vacuoles present

75. Developmental disorders ofDevelopmental disorders of
skeletal musclesskeletal muscles
Floppy infant with delayed motor
development
Nonprogressive myopathies
Persistent proximal muscle atrophy with
weakness
1. Centronuclear myopathy
2. Congenital fiber type disproportion

76. Centronuclear MyopathyCentronuclear Myopathy
AD/ AR/ X linked
CF- Presents from in infancy till 7 th decade.
Extraocular palsies and facial asthenia with
inv. of appendicular muscles.
Theory - arrest in maturation at myotube stage
– hence name myotubular myopathy.

77. Centronuclear MyopathyCentronuclear Myopathy
Bx –
High proportion of fibres
with central nuclei,
+nce of perinuclear halos
Small diameter of fibres
Pred. Of type 1 fibres,
Nuclei exceeds normal
size vesicular chromatin.

78. Congenital fibre type disproportionCongenital fibre type disproportion
 Atrophy of type 1 and hypertrophy of type 2 fibers
 May occur in families
 Clinically at birth, paucity of motor activity and
diminished muscle tone.
 Deformities – hip dislocation , kyphoscoliosis, joint
contracturs.
 Bx-
 Uniformly small
type 1fibres.
 Type 2 fibres- large

79. Myofibrillar myopathiesMyofibrillar myopathies
Group of disoders with genetic defects
manifesting myofibrillar & cytoskeletal
abnormality.
1. Central core disease
2. Multicore disease.
3. Nemaline rod myopathy
4. Desmin myopathy.

80. Central core diseaseCentral core disease
 AD
 Chr.19q13.1
 Affects RYR1gene – inv. Ryanodine receptor prot.
 Type 1 fibres are affected
 Mild , proximal, non progressive muscle weakness.
 Bx –
1. Many fibers show single
centrally located defect or core.
2. More than one core per fiber
may be
encountered.

81. Multi core diseaseMulti core disease
 Congenital, non progressive myopathy
 Generalised weakness and hypotonia.
 Type 1 fibre predominance.
 Bx-
 Numerous , multiple core like structure in majority of
muscle fibres.
 Multicore tend to be
numerous within each fibre.
 PAS/ Trichrome/ NADH-TR –
Stains pale

82. Nemaline rod myopathyNemaline rod myopathy
 More prevalent in females.
 AD/AR
 Mutation of 5 thin filament genes- TPM3 &
Nebulin
 Affects facial and proximal limb muscles.
 CF- Facial dysmorphism
 Bx-
 Rods in majority of fibers
and in numerous number.

83. Desmin MyopathyDesmin Myopathy
 AD
 Childhood
 Missense mutation/ del. – located on 2q35 encodes
desmin..
 Distal weakness, dysphagia, cardiac muscle
involvement.
 In frozen section – with RTC-
smuged area on peripheral
sarcoplasm.
 NADH-TR- Unstained

84. Neuromuscular junction disorderNeuromuscular junction disorder
 Immune mediated
 Slowly progressive
 EMG- diagnostic
 1) MG
 2) Lambert- Eaton syndrome
 Bx- often normal/ nonspecific pattern of atrophy
MG- mod.- severe type-2 fibre atrophy

85. Metabolic diseasesMetabolic diseases
CHO storage -
 Acid maltase deficiency
 Mc-Ardle
 PFK deficiency
Lipid storage diseases
 Carnitine deficiency
 Carnitine Palmitoyl transferase deficiency
Channelopathies

86. Metabolic diseasesMetabolic diseases
1) Acid maltase deficiency
•Type -2 glycogenosis, AR
•mutation at chr. 17 - Mc at exon 18
•Fatal systemic disease of infant
•Adult form is also +nt
•Progressive weakness hypotonia, macroglossia COM &
organomegaly
•Biochemical analysis is must

87. Acid maltase deficiencyAcid maltase deficiency
Acid maltase deficiency-H & E PAS
•BX - PAS+ve diastase labile vacuoles of varying sizes
that replace much of sarcoplasm of the fibres.
•E/M memb bound glycogen filled vacuoles are seen.

88. Metabolic diseasesMetabolic diseases
2) CHO storage -Mc-Ardle disease.
 Type 5 glycogenosis-myophosphorylase deff.
 AR point mut. 11q13
 Childhood / adolescence
 C/F muscle weakness , exercise intolerance
 Bx- Vacuoles located subsarcolemmaly.
Control-
phophorylase
Patient.

89. Metabolic diseasesMetabolic diseases
3) PFK deficiency
Type 7 glycogenosis / Tarui disease
AR, mut.12q13
 Present in childhood
Muscle pain, exercise intolerance
Prolonged exercise leads to nausea, vomitting ,
myoglobinuria HA d/t RBC PFK def.
Frozen section - PAS +ve crescents seen adjacent
to sarcolemma of muscle fibres
Biochemical analysis must

90. Lipid storage diseasesLipid storage diseases
Cytosol Inner mito. Mitochondria
membrane
Acyl- Carnitine Carnitine Acyl
coA Co-A
CPTI CPT- 2
Co-A Acyl Acyl COASH
carnitine carnitine

Deletion of either I.e. CPT 1 & CPT 2 lead to myopathy
Histology – Myofibrils are seperated by vacuoles that stain with ORO /
SBB with in muscle fibre


91. Lipid storage diseaseLipid storage disease
Deletion of either I.e. CPT 1 & CPT 2 lead
to myopathy
Histology – Myofibrils are seperated by
vacuoles that stain with ORO / SBB with in
muscle fibre
Predominantly type-1 fibres are affected

92. Mitochondrial MyopathiesMitochondrial Myopathies
1) Kearns Sayre Syndrome
2) MELAS
3) MERRF
Deficiencies of enzymes of the respiratory chain
affect more severely muscle and brain
Impairment of intramitochondrial protein synthesis
Deformed enlarged mitochondria forming aggregates
Ragged red fibres.
Muscle involvement is characterized by weakness and
ophthalmoplegia.

93. Mitochondrial MyopathyMitochondrial Myopathy
The red color -due to large numbers of
abnormal mitochondria that represent a
compensatory proliferation.
Ragged-
Coarse and disorganized fibers

94. ChannelopathiesChannelopathies
Myopathies with periodic paralysis-
Due to abnormality in Na/Ca channels
C/F myotonia , relapsing episodes of hypotonic paralysis
EM -Vacuoles represent dilated sacs of sarcoplasmic
reticulum
Bx- non specific findings-
-Variation in fibre size
-Fibre regeneration &
degeneration
-Inc.in internal nuclei
-Endomysial fibrosis
-Vacuolar change

95. Toxic & Drug induced myopathyToxic & Drug induced myopathy
Chloroquine - vacuolar myopathy – proximal
myopathy
Procamamide & Penicillamine - inflammatory
myopathy
Steriod – type 2 Atrophy
Ethanol,AZT - Subacute
necrotising myopathy
Hypothyroidism –Atrophy
internalization of nuclei
Tyrotoxicosis- Necrosis
degeneration, regeneration,
lymphocytic infiltrate

96. Biochemical investigations in muscleBiochemical investigations in muscle
diseasedisease
 Always done before biopsy.
CK-
 used as a single most useful marker
 Elevated in pt. With muscle disease but it may be normal in
slowly progressive disease.
Main use-
1. To differentiate between types of dystrophies
 In DMD, 10-100 times normal
 Raised before 1 yr of s/s, Peak at 3 yrs.
 Other dystrophies- elevation is lower except in LGD
2. Floppy infant syndrome-Only congenital myopathy whr CK
levels are raised.

97. Biochemical investigations inBiochemical investigations in
muscle diseasesmuscle diseases
D/D of elevation of CK-
1. Motor neuron diseases.
2. GBS
3. Drugs- Steroids
4. Hypothyroidism/Hypopartathyroidism
5. Trauma
Remember-
1. CK levels are not raised in neurogenic atrophy.
2. Elevation of CK without weakness –No
myopathy.

98. Biochemical investigations in muscleBiochemical investigations in muscle
diseasesdiseases
3. CK isoenzymes are not advocated, as there is
elevation of CKMM, CKMB.
Other enzymes used are- Aldolase, AST, ALT, LDH.
1. Aldolase –more sensitive than CK in PM.
2. AST, ALT, LDH –measured as screening
procedures.
Elevation of either advocate prompt CK
measurement.

100. SummarySummary
What to be seen on
1. Transverse
 Most of abnormalities are
seen on TS
 Size, shape, position of
nuclei, inflammation,
endomysial fibrosis, .Ring
fibers ,cores, Targets ,
2. Longitudinal
 Striations
 Position of
nuclei,inflammation
segmental necrosis,
Fiber splitting
Neurogenic cause Primary myopathic cause
1.Atrophy – angular
- group
2.Type grouping
3.Target fibre
1.variation in fibre size
2.Fibre degeneration &
Necrosis

101. Atrophy
Angular
Random atrophy+ Necrosis
1.Neurogenic-
Group
atrophy,targets
Type grouping
2. LGD-
hypertrophy,
fibresplitting
Myopathic
Inflammation
Endomysial
fibrosis
Nuclear changes
Sarcoplasmic
changes1.PM, IBM-
Endomysial
2.DM-
Perivascular
3.FSHD
-Perivascular -
Dysrophy
1, MD-Multiple nuclei
2. Centonuclear-central
nuclei in each fibre
1.Ring fib-MD
2.Core-
Centralcore/multicore
3.Nemaline rods-
Nemaline myo.
4.Vacuole-Storage
dis.
5.RRF-
Mitochond.myo.

103. Perifascicular atropy

104. Normal histology of MuscleNormal histology of Muscle