MSK HRP Flashcards
What do elastic fibres have?
Presence of numerous bundles of branching elastic fibres in the cartilage matrix
Elastic fibres are particularly dense in the immediate vicinity of the chondrocytes
Where are elastic fibres seen?
Seen in external ear, external auditory meatus, epiglottis, parts of laryngeal cartilages and walls of eustachian tubes
What is fibrocartilage?
Presence of alternating layers of hyaline cartilage matrix and thick layers of dense collagen fibres oriented in the direction of functional stresses
Chondrocytes are typically arranged in rows between the dense collagen layers within the lacunae in the matrix
Where is fibrocartilage seen?
Found in the IV discs, some articular cartilages, the pubic symphysis
Where is hyaline cartilage seen?
Found in the nasal septum, larynx, tracheal rings, most articular surfaces, sternal ends of the ribs
What does hyaline cartilage look like?
Glassy, opalescent, firm in consistency
The chondrocytes are arranged in clusters – usually 2-4 cells
Hyaline cartilage
Get the glassy appearance of the matrix – very homogenius – see perichondrium also - Cells are grouped within the lacunae (the spaces) There is the nucleus inside but due to the staining may not see as well
Fibrocartilage
Cells are arranged in rows – and between these you have collagen fibres – well arranged
Elastic cartilage
Presence of fine elastic fibres – very close to the cells – see them very thin and fine
Compact bone
Trabecular (cancellous/spongey) bone
What is this called?
Haversian canal
What are the 6 functional and morphological stages in transition between epiphyseal cartilage and new bone?
Zone of REVERSE cartilage
Zone of PROLIFERATION
Zone of MATURATION
Zone of HYPERTROPHY AND CALCIFICATION
Zone of CARTILAGE DEGENERATION
OSTEOGENIC zone
Where is hyaline cartilage found?
What is its appearance?
Tracheal cartlage
Blue, glassy
Where is fibrocartilage found?
What is its appearance?
Intervertebral discs
Chondrocytes in rows interspersed between regularly arranged collagen fibres
Where is elastic cartilage found?
What is its appearance?
Pinna
Similar to hyaline cartilage but a lot of thread like elastic fibre
The glenoidal and acetabular labrum are of what type of cartilage?
Fibrocartilage
Define ossification
Bone formation
What are the two types of ossification you normally see during the development of bone?
Membranous and endochral
What is spongey bone?
Bone at ends of long bones with trabeculae
What is the functional unit of compact bone?
Osteon or haversian system
What does the T and M stand for in this image?
Trabeculae and marrow
Where are osteocytes?
Found within lacunae in bone
What are osteoblasts associated with?
Periosteum
What are osteoclast?
Large infrequent cells with ruffled borders – they are important in bone remodelling and are formed from the macrophage cell line
What is an osteoid?
Unmineralised organic bone of the bone matrix that forms prior to maturiation of bone
What is a malignant bone timour in young children?
Ewings sarcoma
What is the typical presentation of ES?
Leg pain during exercise
What is the radiology seen on ES?
Periostel onion skin reaction
What is the histopathology seen in ES?
Small round blue cell tumour, monomorphic tumour cells, granular chromatin, necrosis
What is a benign tumour seen in older children?
Osteoma
What is the typical presentation of an osteoma?
Leg pain
What is the radiology seen in an osteoma?
Osteoma <2cm> Osteoblastoma round lesion, radiolucent with areas of mineralisation, ‘Hot’ on bone scan
What is the histopathology seen in osteoma?
Sharp margin, haphazard trabeculae, prominent osteoblasts/scattered osteoclasts
What is a malignant bone tumour seen in older children?
Osteosarcoma
What is the presentation of osteosarcoma?
Leg pain
What does the radiology in osteosarcoma look like?
Large, destructive, poorly defined, ‘Cloud-like’ appearance, may elevate periostium – ‘Codman’s triangle’
What is the histopathology seen in osteosarcoma?
High grade ‘spindle cell’ lesion, produces osteoid matrix
What is the benign bone tumour seen in older children/young adult?
Endochondroma
What is the presentation of endochondroma?
25 year old, painless swelling distal femur
What is the radiology in an endochrondroma?
Central intramedullary expansile growth, intact cortex, ‘Ring calcifications’, peripheral ossification
What is the histopathology in an endochondroma?
Hyaline cartilage, haphazard chondrocytes, no nuclear atypia
What is a benign bone tumour seen in middle aged?
Osteochondroma
What is the presentation of an osteochondroma?
40 year old, hard lump (longstanding) on leg
What is the radiology of an osteochondroma?
Exophytic bony projection capped by cartilage, cortex and medulla contiguous with bone
What is the histopathology of an osteochondroma?
From superficial to deep: Cartilaginous cap, Endochondreal ossification zone, Regular trabecular bone
What are the malignant bone tumours seen in older people?
Chondrosarcoma and myeloma
What is the typical presentation of a chondrosarcoma?
60 year old, several month history of painful swelling
What is the radiology of a chondrosarcoma?
Poorly marginated tumour (metadiaphyseal), matrix calcifications, infiltrates medullary cavity/cortex
What is the histopathology of a chondrosarcoma?
Cartilagenous matrix, increased numbers of spindled chondrocytes, rare mitoses, permeation through viable lamellar bone
What is the presentation of a myeloma?
60 year old, several month history of malaise, abnormal bloods
What does the radiology look like in a myeloma?
Multiple discrete ‘punched-out’ lesions, well defined borders
What is the histopathology like in a myeloma?
Marrow infiltrated by diffuse sheets of plasma cells, eccentric nucleus, ‘Clock-face’ chromatin pattern
What is the presentation of a metastatic adenocarcinoma?
60 year old, several month history of malaise
What is the radiology of a metastiatic adenocarcinoma?
Usually osteolytic/destructive; may be osteoblastic/sclerotic/mixed
What is the histopathology of a metastatic adenocarcinoma?
Usually resembles primary, reactive stromal changes often seen
