here is included Notes On Muscle pathology, making it simple , it helps understand and differentiate between muscle pathologies.

2. Inflammatory Myopathies
Disease Poly Myositis Dermatomyositis Inclusion Body Myositis
Tissue involved Inf. Of Skeletal Muscle Inf. Of Skeletal Muscle Inf. Of Skeletal Muscle
Fibre Fibre & Skin Fibre
Age Adults Children & Adults Adults>50 years
Clinical Presentations Bilateral Proximal Bilateral Proximal Asymmetrical Distal
Muscle Weakness Muscle Weakness. Muscle Weakness
Skin Rash of Upper
Eyelid
Periorbital edema
Microscopic Features Endomysial lymphocytic Perimysial and vascular Cytoplasmic Vacuoles
Infiltration( CD 8) lymocytic infiltration and basophilic granules
and amyloid.
Skeletal muscle fibre Perifasciular Fibre
regeneration and Atrophy EM: Filamentous
degeneration Inclusions
Skeletal muscle fibre
regeneration and
degeneration
Cancer Risk: Increased Risk Of :
Lung , Stomach &
Ovarian Cancers.

3. Myasthenic Syndromes.
Disease Myasthenia Gravis Eaton-Lambert Gullian- Barre
Syndrome Syndrome
Mechanism Autoantibodies against Autoantibodies against Antibodies against
Ach. Receptors in NMJ Ca. Ion Channels in NMJ Schwann cells
leading to
Peripheral Nerve
Demyelination &
inflammation
Associated Diseases Thymoma or Thymic Small Cell Lung Cancer Preceded by Viral
hyperplasia illness
Gender Females > Males
Clinical Presentation Muscular weakness of Proximal Muscle Muscle weakness
Body but predominantly Weakness with an ascending
affecting: paralysis.
Facial Muscles
Extraoccular Muscles with Loss of Deep
Ptosis tendon reflexes
May Involve Respiratory May Involve
Muscles and cause Death Respiratory
Muscles & cause
death
Alleviating Factors Weakness worsens with Weakness improves with
repeated contractions. repeated contractions
Diagnosis Nerve Conduction
Studies.

4. Muscular Dystrophy
Disease Duchene Muscular dystrophy Becker Muscular Dystrophy
Incidence Most Common & Severe Form of Less Common & Mild Form of
Muscular dystrophy Muscular dystrophy
Genetics X-linked Recessive X-linked Recessive
Mutations Mutations lead to Absence of Mutations lead to Alteration of
Dystropin protein Dystropin protein
Clinical Presentations Rapidly Progressive Muscular Slowly Progressive Muscular
Weakness weakness.
Proximal weakness of Shoulder Muscle weakness of Pelvis and
and pelvic Girdle Legs
Calf Pseudohypertrophy
Heart Failure and arrhythmia Heart involvement is rare.
Respiratory insufficiency and
infections
Age 5- Onset of symptoms Later onset with variable
progression and may lead a
Age 10- Wheel chaired normal life span
Age 20- Respiratory Failure and
death
Microscopic Features. Fibrosis and Fatty infiltration and
Necrosis
Skeletal muscle degeneration Skeletal muscle degeneration
and regeneration and regeneration
Diagnosis Muscle Biopsy Muscle Biopsy
DNA Analysis DNA Analysis

5. Benign Soft Tissue tumors
Tumors Type of cells Locations
Lipoma Adipose tissue Trunk
( Most Common) Neck
Proximal Extremities
Dermatofibroma Dermal Spindle cell Extremities
(Forms a red nodule that can be
squeezed)
Fibromatosis Fibrous tissue Infiltrates Muscle tissue
Rhabdomyoma Striated Muscle cells Heart
Tongue
Vagina
Leiomyoma Smooth muscle cells Uterus
Stomach
Malignant Soft Tissue Cancers
Cancers Type of cells Locations
Liposarcoma Adipose tissue Thigh
( Most Common) & lipoblasts Retroperitoneum
Fibrosarcoma Thigh
Upper Limb
Malignant Fibrous Pleomorphic cells Thigh
Histocytoma Retroperitoneum
Embryonal Striated muscle cells Male – Mass seen protruding
Rhabdomyosarcoma form penis
Female- Mass seen protruding
from Vagina
Leiomyosarcoma Smooth Muscle cells Uterus
GIT
Neurofibrosarcoma Nerve cells Peripheral Nervous system
Synovial Sarcoma Glands and spindle cells Around Joints