MUSCULOSKELETAL PATHOLOGY - 5 Flashcards
Covers Bone and Soft tissue neoplasms
most common tumor of bone
Metastasis
3 causes for secondary osteosarcoma
Paget disease, bone infarcts, and prior radiation
What genetic phenomenon accounts for the occurence of Osteosarcoma and retinoblastoma in the same individual?
Loss of heterozygosity
Mutation assoc with the tumor described below?
curvilinear trabeculae of woven bone surrounded by a moderately cellular fibroblastic proliferation (Chinese letter pattern)
No osteoblastic rimming
activating mutations in the GNAS1 gene–>increased cAMP
Diagnosis?
20 to 50 years
solitary metaphyseal lesion
tubular bones of the hands and feet
Xray attached
Chondroma
What’s the radiologic finding assoc with this tumor?
20–40 years
epi/metaphysis
Microscopic image findings attached
eccentric, expansile, lytic lesion, surrounded by a thin bony shell
(soap bubble)
The tumor described is a giant cell tumor
1. Diagnosis?
10–30 yr
metaphyseal lesion
Xray attached.
2. What’s the microscopic finding?
- Osteochondroma
- cap is composed of benign hyaline cartilage, underlying stalk contains cancellous bone
Osteoid osteoma/ osteoblastoma?
Larger than 2 cm
involves the axial skeleton
Dull pain that is unresponsive to aspirin
purely radiolucent lesion, with only a thin shell of surrounding bone
Osteoblastoma
- Multiple osteochondromas are assoc with which syndrome?
- What’s the risk?
- multiple hereditary exostosis syndrome
- 5% to 20%, progress to chondrosarcoma
Syndromes assoc with multiple enchondromas
- Ollier disease - Multiple enchondromas.
- Maffucci syndrome - Multiple enchondromas and hemangiomas
most common tumor arising within bone
MULTIPLE MYELOMA
Microscopic features of osteosarcoma
Fine, lacelike pattern of neoplastic bone produced by anaplastic malignant tumor cells
Osteochondroma or chondrosarcoma?
See the attached image of the gross specimen
Osteochondroma
What’s the microscopic feature of the tumor described below?
20 to 50 years
solitary metaphyseal lesion
tubular bones of the hands and feet
Xray - circumscribed lucencies with central irregular calcifications, a sclerotic rim and an intact cortex
Gross specimen: gray-blue and translucent
well circumscribed nodule of hyaline cartilage containing benign chondrocytes
Diagnosis?
metaphyses
knee
gross image attached
microscopy shows fine ,lacelike pattern of neoplastic bone
Radiologic: Codman triangle and sunburst pattern seen
Osteosarcoma
Radiologic sign assoc with osteosarcoma
Codman triangle - triangular shadow between the cortex and raised ends of periosteum
Sunburst pattern - stretching of Sharpey fibers, woven bone produced by the sarcoma and the periosteal reaction of the host bone
See the attached image. Activity of which cell type is responsible for this finding?
Osteoclasts
(The image is showing multiple osteolytic lesions, indicative of purely lytic metastases)
See the attached image. Activity of which cell type is responsible for this finding?
Osteoblasts
(The image is showing multiple osteoblastic lesions, indicative of purely blastic metastases)
Microscopic finding assoc with osteoid osteoma
haphazardly interconnecting trabeculae of woven bone rimmed by prominent osteoblasts.
The intertrabecular spaces are filled by vascularized loose connective tissue
What accounts for the presence of giant cells in this tumor?
20–40 years
epi/metaphysis
Microscopic image findings attached
neoplastic mononuclear cells produce RANKL and induce osteoclast formation
polyostotic fibrous dysplasia+ soft tissue myxomas
Mazabraud syndrome
Microsocpic finding?
arise in the axial skeleton - pelvis, shoulder, and ribs
painful, progressively enlarging mass
Gross specimen: large bulky tumor, nodules of glistening gray-white, translucent cartilage
Diagnosis is Chondrosarcoma.
Microscopic features include:
a. cartilage infiltrates the marrow space and surrounds pre-existing bony trabeculae
b. Myxoid matrix
polyostotic fibrous dysplasia+ “café-au-lait” spots+ precocious puberty
McCune Albright syndrome
Osteoid osteoma/ osteoblastoma?
less than 2 cm in diameter
predilection for the appendicular skeleton
severe nocturnal pain relieved by aspirin
Radiograph: immature osseous tissue (the nidus) surrounded by a halo of dense reactive bone
Osteoid Osteoma
What’s the characteristic microscopic morphology?
majority of the cases younger than 20 years
diaphysis
femur and the flat bones of the pelvis
tenderness, warmth and swelling over affected joint
Xray shows: layers of reactive bone deposited in an onion-skin fashion
sheets of uniform small, round cells, scant cytoplasm and Homer-Wright rosettes
What’s the tumor associated with the following?
Familial adenomatous polyposis + congenital hypertrophy of retinal pigment epithelium+ impacted/supernumerary teeth
The syndrome described is Gardner Syndrome
The bone tumor assoc with this syndrome is an osteoma
three most common malignant tumors of bone excluding multiple myeloma and metastasis
osteosarcoma, chondrosarcoma, and Ewing sarcoma
Examples of malignant tumors producing purely lytic metastatic bone lesions
Kidney, lung, GI tract, malignant melanoma
Genetic abnormality assoc with Ewing Sarcoma family of tumors
(11;22) (q24;q12) translocation
generating in-frame fusion of the EWS gene on chromosome 22 to the FLI1 gene
Examples of malignant tumors producing purely blastic metastatic bone lesions
Prostatic carcinoma
What is the pathogenesis of the condition described below?
wrist joint
firm, fluctuant, pea-sized translucent nodule
The condition described is a ganglion.
Pathogenesis: cystic or myxoid degeneration of connective tissue
Microscopic features of the condition described below?
soft, mobile, and painless mass
arises in the subcutis
benign
The condition described is a lipoma.
Features include: Well encapsulated mass of mature adipocytes. (polygonal cells with clear cytoplasm and peripherally placed nuclei)
What’s your diagnosis?
Malignant soft tissue tumor originating from adipocytes
Location: deep soft tissues of the proximal extremities and in the retroperitoneum
Liposarcoma
benign neoplasms of skeletal muscle
Rhabdomyoma
Cradiac rhabdomyomas are assoc with which condition?
Tuberous sclerosis
What is the IHC marker for the condition described below?
malignant mesenchymal tumor with skeletal muscle differentiation
The tumor is rhabdomyosarcoma
IHC Marker is Desmin
< 5years of age
polypoid, rounded, bulky, grapelike masses protruding from the vagina
Clinical image attached
What will the microscopic image show?
sheets of small round cells, IHC positive for Desmin
This is embryonal rhabdomyosarcoma
most common soft tissue sarcoma of childhood and adolescence
alveolar and embryonal rhabdomyosarcoma
