Musculoskeletal practical block

Musculoskeletal block Pathology practical

Normal anatomy and histology

The overall structure of a long bone

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Here is normal cancellous bone as seen under polarized light microscopy, which highlights the lamellar structure. The bony spicules are even, with occasional lacunae containing osteocytes. Cellular marrow is seen between the spicules of bone.

Gross pathology and histopathologyCase no. 1A 22 years old male presented with localized pain above his right knee joint with recurrent- fever. Later, he had a discharging sinuses from the skin overlying the right knee. What is the most likely diagnosis ?

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This is chronic osteomyelitis. Note the fibrosis of the marrow space accompanied by chronic inflammatory cells. There can be bone destruction with remodelling. Osteomyelitis is very difficult to treat.

OsteomyelitisCase no. 2A 35 years old debilitated man presented to the orthopedic clinic with back pain, low grade fever, marked elevation of sedimentation rate and recent kyphosis and scoliosis . The patient has a history of coughing up blood, fever, chills, night sweats, weight loss, pallor , and often a tendency to fatigue very easily.

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Fracturenecrosis

Section of bone shows granuloma formation with epithelioid like cells , langhans-type giant cells and rim of lymphocytes granulomarim of lymphocytes Including inside :epithelioid like cellslanghans-type giant cellsSection of bone shows granuloma formation with epithelioid like cells , langhans-type giant cells and rim of lymphocytes .192- Spinal TB - Potts Disease (Tuberculous osteomyelitis)Case no. 3A 40 years old woman complains of low grade fever , malaise- and stiffness in her joints each morning .

Key information : Usually with womenAffecting wrist & hand regionThere will be malaise (not feeling well )

Swollen and slightly deformed interphalangeal joints. Swelling in small joints Tumor necrosis factor (TNF) plays central role in the pathogenesis of this disease.23

Rheumatoid arthritis affecting the head of femur. The synovium becomes edematous, thickened and hyperplastic and transforming its smooth contour to one covered by delicate and bulbous fronds leaf-like.

The normal head will be shiny in appearance which is it not here 24

Section shows marked synovial hypertrophy with formation of villi (plural of villus : small vascular process-small projection)There are finger-like projections 25

Section of synovial tissue showingHyperplastic synovium which is infiltrated by dense chronic inflammatory cells including many lymphocytes and plasma cells. 3- Rheumatoid arthritisCase no. 4An obese 56 years old woman presented with bilateral localized pain to her knees, hands and difficulty in walking .

Progressive erosion of articular cartilage, eburnated (hardening of the bone) articular surface , subchondral cyst and residual- articular cartilagePredisposing factors for osteoarthritis are marked obesity , previous injuries to a joint , diabetes and deformed joint .Progressive erosion of articular cartilage, eburnated articular surface , subchondral cyst and residual articular cartilage(Osteoarthritis)

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Mushroom-shaped osteophytes (bony outgrowths ) and splitting- of articular cartilage . There is absence of inflammation .Mushroom-shaped osteophytes (bony outgrowths ) develop at the margins of the articular surface and are capped by fibrocartilage and hyaline cartilage that gradually ossify .(Osteoarthritis)

314- OsteoarthritisCase no. 5A 16 years old male was found to have a small swelling protruding from upper part of his leg with local pain .

This is an osteochondroma of tibial bone. This lesion appears as a bony projection (exostosis). Most are solitary, incidental lesions that may be excised if they cause local pain. There is a rare condition of multiple osteochondromatosis marked by bone deformity and by a greater propensity for development of chondrosarcoma.This is an osteochondroma of bone. This lesion appears as a bony projection (exostosis). Most are solitary, incidental lesions that may be excised if they cause local pain. There is a rare condition of multiple osteochondromatosis marked by bone deformity and by a greater propensity for development of chondrosarcoma.35A bluish-white cartilagenous cap(chondroid)overlies the bony cortex.

These are probably not true neoplasms, but they are a mass lesion that extends outward from the metaphyseal region of a long bone.These are probably not true neoplasms, but they are a mass lesion that extends outward from the metaphyseal region of a long bone.36

The microscopic appearance of an osteochondroma displays the benign cartilagenous cap at the left upper and the bony cortex at the right lower.

This bone growth, though benign, can sometimes cause problems of pain and irritation that leads to removal surgically.

It is a benign tumor with very rare incidence of malignant transformation

The microscopic appearance of an osteochondroma displays the benign cartilagenous cap at the left upper and the bony cortex at the right lower. This bone growth, though benign, can sometimes cause problems of pain and irritation that leads to removal surgically.

37Osteochondroma of bone.

This is an osteochondroma of bone.

385- Osteochondroma (osteochondroma exostosis)

Case no. 6An 18 years old female presented to the rheumatology clinic with 2 months history of pain and swelling in her upper thigh with weight loss . Wight loss -> malignant

Conventional osteosarcoma

43Mass lesion involving the upper end of the tibial bone. The mass show pale(grayish white mass), yellowish cut surface with few hemorrhagic areas(red).

Conventional osteosarcomaMass lesion involving the upper end of the tibia bone. The mass show pale, yellowish cut surface with few hemorrhagic areas.44

Malignant osteoid, Malignant pleomorphic cells showing abnormal mitosesOsteosarcoma

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The etiology :Pagets disease , Radiation, fibrous dysplasia

Predisposing factors which may lead to the development of the lesion : Pagets disease , Radiation, fibrous dysplasia466-Osteosarcoma

Case no. 7Case no. 7

51A 3 years old boy presented to his pediatrician with complaint of his parents from difficulty in walking , poor balance , and frequent falls . Laboratory investigation shows elevated creatine kinase . Muscle biopsy show absence of dystrophin by western blot analysis . What is your provisional diagnosis?

clinical features seen in picture : Deformed back, foot drop and asymmetrical calf muscles atrophyclinical features seen in picture : Deformed back, foot drop and asymmetrical calf muscles atrophy53

DMD showing variations in muscle fiber size , increased endomysial connective tissue , and regenerating fibers (blue hue) . Also there is fiber loss and adipose tissue infiltrationEtiology: Abnormalities in the dystrophin gene located on the short arm of the X-chromosome.

54Etiology: Abnormalities in the dystrophin gene located on the short arm of the X-chromosome.

55Note again the atrophy/hypertrophy scenario

NORMALDMD56Dystrophin, an intracellular protein, forms an interface between the cytoskeletal proteins and a group of transmembrane proteins 7-Duchenne muscular dystrophyCase no.8A 52-year-old woman presents with 6-month history of progressive muscle weakness and a skin rash.Physical examination is remarkable for a diffuse purple/red discoloration of the skin over her cheeks, nose, and eyelids. Examination confirms proximal muscle weakness.Laboratory findings show an increase in creatine kinase (10 times the normal).

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The histologic appearance of muscle shows perifascicular atrophy of muscle fibers and inflammation .

Patient usually have positive antinuclear antibody (ANA) and increased creatine kinase .

The histologic appearance of muscle shows perifascicular atrophy of muscle fibers and inflammation .628-Dermatomyositis