MUSCULOSKELETAL PATHOLOGY - 5

Question 1

most common tumor of bone

Answer 1

Metastasis

Question 2

3 causes for secondary osteosarcoma

Answer 2

Paget disease, bone infarcts, and prior radiation

Question 3

What genetic phenomenon accounts for the occurence of Osteosarcoma and retinoblastoma in the same individual?

Answer 3

Loss of heterozygosity

Question 4

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

Answer 4

activating mutations in the GNAS1 gene–>increased cAMP

Question 5

Diagnosis?

20 to 50 years

solitary metaphyseal lesion

tubular bones of the hands and feet

Xray attached

Answer 5

Chondroma

Question 6

What’s the radiologic finding assoc with this tumor?

20–40 years

epi/metaphysis

Microscopic image findings attached

Answer 6

eccentric, expansile, lytic lesion, surrounded by a thin bony shell

(soap bubble)

The tumor described is a giant cell tumor

Question 7

1. Diagnosis?

10–30 yr

metaphyseal lesion

Xray attached.

2. What’s the microscopic finding?

Answer 7

1. Osteochondroma
2. cap is composed of benign hyaline cartilage, underlying stalk contains cancellous bone

Question 8

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

Answer 8

Osteoblastoma

Question 9

1. Multiple osteochondromas are assoc with which syndrome?
2. What’s the risk?

Answer 9

1. multiple hereditary exostosis syndrome
2. 5% to 20%, progress to chondrosarcoma

Question 10

Syndromes assoc with multiple enchondromas

Answer 10

1. Ollier disease - Multiple enchondromas.
2. Maffucci syndrome - Multiple enchondromas and hemangiomas

Question 11

most common tumor arising within bone

Answer 11

MULTIPLE MYELOMA

Question 12

Microscopic features of osteosarcoma

Answer 12

Fine, lacelike pattern of neoplastic bone produced by anaplastic malignant tumor cells

Question 13

Osteochondroma or chondrosarcoma?

See the attached image of the gross specimen

Answer 13

Osteochondroma

Question 14

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

Answer 14

well circumscribed nodule of hyaline cartilage containing benign chondrocytes

Question 15

Diagnosis?

metaphyses

knee

gross image attached

microscopy shows fine ,lacelike pattern of neoplastic bone

Radiologic: Codman triangle and sunburst pattern seen

Answer 15

Osteosarcoma

Question 16

Radiologic sign assoc with osteosarcoma

Answer 16

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

Question 17

See the attached image. Activity of which cell type is responsible for this finding?

Answer 17

Osteoclasts

(The image is showing multiple osteolytic lesions, indicative of purely lytic metastases)

Question 18

See the attached image. Activity of which cell type is responsible for this finding?

Answer 18

Osteoblasts

(The image is showing multiple osteoblastic lesions, indicative of purely blastic metastases)

Question 19

Microscopic finding assoc with osteoid osteoma

Answer 19

haphazardly interconnecting trabeculae of woven bone rimmed by prominent osteoblasts.

The intertrabecular spaces are filled by vascularized loose connective tissue

Question 20

What accounts for the presence of giant cells in this tumor?

20–40 years

epi/metaphysis

Microscopic image findings attached

Answer 20

neoplastic mononuclear cells produce RANKL and induce osteoclast formation

Question 21

polyostotic fibrous dysplasia+ soft tissue myxomas

Answer 21

Mazabraud syndrome

Question 22

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

Answer 22

Diagnosis is Chondrosarcoma.

Microscopic features include:

a. cartilage infiltrates the marrow space and surrounds pre-existing bony trabeculae
b. Myxoid matrix

Question 23

polyostotic fibrous dysplasia+ “café-au-lait” spots+ precocious puberty

Answer 23

McCune Albright syndrome

Question 24

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

Answer 24

Osteoid Osteoma

Question 25

**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

Answer 25

sheets of uniform small, round cells, scant cytoplasm and Homer-Wright rosettes

Question 26

**What's the tumor associated with the following?** Familial adenomatous polyposis + congenital hypertrophy of retinal pigment epithelium+ impacted/supernumerary teeth

Answer 26

The syndrome described is **Gardner Syndrome** The bone tumor assoc with this syndrome is an **osteoma**

Question 27

three most common malignant tumors of bone excluding multiple myeloma and metastasis

Answer 27

osteosarcoma, chondrosarcoma, and Ewing sarcoma

Question 28

Examples of malignant tumors producing purely lytic metastatic bone lesions

Answer 28

Kidney, lung, GI tract, malignant melanoma

Question 29

Genetic abnormality assoc with Ewing Sarcoma family of tumors

Answer 29

(11;22) (q24;q12) translocation generating in-frame fusion of the EWS gene on chromosome 22 to the FLI1 gene

Question 30

Examples of malignant tumors producing purely blastic metastatic bone lesions

Answer 30

Prostatic carcinoma

Question 31

**What is the pathogenesis of the condition described below?** wrist joint firm, fluctuant, pea-sized translucent nodule

Answer 31

The condition described is a _ganglion._ Pathogenesis: c**ystic or myxoid degeneration of connective tissue**

Question 32

**Microscopic features of the condition described below?** soft, mobile, and painless mass arises in the subcutis benign

Answer 32

The condition described is a _lipoma._ Features include: **Well encapsulated mass of mature adipocytes**. (polygonal cells with clear cytoplasm and peripherally placed nuclei)

Question 33

**What's your diagnosis?** Malignant soft tissue tumor originating from adipocytes Location: deep soft tissues of the proximal extremities and in the retroperitoneum

Answer 33

Liposarcoma

Question 34

benign neoplasms of skeletal muscle

Answer 34

Rhabdomyoma

Question 35

Cradiac rhabdomyomas are assoc with which condition?

Answer 35

Tuberous sclerosis

Question 36

**What is the IHC marker for the condition described below?** malignant mesenchymal tumor with skeletal muscle differentiation

Answer 36

The tumor is _rhabdomyosarcoma_ IHC Marker is **Desmin**

Question 37

\< 5years of age polypoid, rounded, bulky, grapelike masses protruding from the vagina Clinical image attached **What will the microscopic image show?**

Answer 37

sheets of small round cells, IHC positive for Desmin This is embryonal rhabdomyosarcoma

Question 38

most common soft tissue sarcoma of childhood and adolescence

Answer 38

alveolar and embryonal rhabdomyosarcoma