Rub/Rob Bone/Tissue

Question 1

Rub 3: Congenital deficiency of 21-hydroxylase can eventually lead to

Answer 1

premature closure of the epiphyses and stunted growth

Question 2

Rub 4: If a fracture site does not heal, the condition is

Answer 2

nonunion; continued movement at the unhealed fracture site could also lead to pseudoarthrosis, a condition in which joint-like tissue is formed

Question 3

Rub 5: Multiple lytic lesions associated with keratin-positive cells strongly suggest

Answer 3

metastatic bone cancer

Question 4

Rub 6: Osteopetrosis characterized by

Answer 4

1. retention of primary spongiosum with its cartilage cores
2. lack of funnelization of the metaphysis
3. thickened cortex;
   “marble bone”

Question 5

Rub 9: Osteonecrosis refers to

Answer 5

the death of bone and marrow in the absence of infection; think trauma, thrombi, emboli, and CS; Legg-Calve-Perthes disease refers to osteonecrosis in the femoral head in children

Question 6

Rub 10: Hematogenous osteomyelitis primarily affects

Answer 6

the metaphyseal area of the long bones (knee, ankle, hip) b/c of the unique vascular supply in this region

Question 7

Rub 28: Malignant fibrous histiocytoma is a

Answer 7

soft tissue tumor that contains foci of histiocytic (macrophage) differentiation and is the most frequent sarcoma encountered after radiation therapy; think spindle-shaped tumor cells in whorled (storiform) pattern adjacent to pleomorphic fields

Question 8

Rub 29: Synovial sarcoma is a

Answer 8

highly malignant soft tissue tumor that arises in the region of a joint; think adolescents and young adults as a painful or tender mass in vicinity of a large joint; spindle-shaped mesenchymal cells and cuboidal epi-like cells

Question 9

Rob 7: Rhabdomyosarcoma is the most

Answer 9

common sarcoma in children; marks with Ab to vimentin, an intermediate cytoplasmic filament by immunoperoxidase staining

Question 10

Rob 8: Nodular fasciitis is a

Answer 10

reactive fibroblastic proliferation that is seen in the upper extremities and trunk of young adults, sometimes occurring after trauma

Question 11

Rob 10: With advancing age, the ability of osteoclasts to divide and lay down osteoid is

Answer 11

reduced as osteoclast activity increases, giving rise to accelerated bone loss, aka osteoporosis; when osteoblasts make less OSTEOPROTEGRIN, that accelerates bone loss

Question 12

Rob 12: Synovial sarcomas can be found around

Answer 12

a joint or in deep soft tissues b/c they arise from mesenchymal cells; most show the t(X;18) translocation

Question 13

Rob 19: Parathyroid adenomas secrete PTH and cause

Answer 13

primary hyperPTism; excessive PTH activates osteoclastic resorption of bone; microfracures within the areas of bone resorption give rise to hemorrhages, causing an influx of macrophages and ultimately reactive fibrosis

Question 14

Rob 20: In children with no history of previous illness with pyogenic osteomyelitis, think

Answer 14

S aureus; for neonates, think H influenzae and group B strep; with sickle cell anemia think Salmonella

Question 15

Rob 21: In a Dupuytrem contracture, think

Answer 15

mature fibroblasts furrounded by dense collagen; hard firm lesion of this size unlikely to be malignant

Question 16

Rob 27: What is an important determinant of subsequent risk of osteoporosis and its complications?

Answer 16

Total bone mass

Question 17

Rob 28: Monostatic fibrous dysplasia is

Answer 17

a benign tumor-like condition; think of women bone in the middle of benign-looking fibroblasts; local deformity and occasionally fracture can occur

Question 18

Rob 29: Infectins with what two organisms are most common during the neonatal period?

Answer 18

Group B strep and E coli

Question 19

Rob 35: TB prefers to go to which regions after hematogenous spread regarding the skeletal system?

Answer 19

Long bones and vertebrae; think destructive lesion in the vertebrae with extension of the disease along the psoas muscle = TB osteomyelitis

Question 20

Rob 41: Elevated alk phos level in an older adult should raise suspicion of

Answer 20

bone mets, particularly if there is pathologic fracture resulting from a bone lesion rather than trauma; primary sites include the breast, prostate, lung, kidney, thyroid

Question 21

Rob 43: Avascular necrosis of bone represents a

Answer 21

localized area of bone infarction, most often in a metaphyseal medullary cavity or subchondral epiphyseal location; think FEMORAL HEAD; consider hemoglobinopathies, fracture, hypercoag states, hyperlipidemia

Question 22

Rob 46: Achondroplasia most often the result of a

Answer 22

spontaneous new mutation in the FGFR3 gene, leading to abnormal cartilage proliferation at growth plates and affecting mainly endochondral bone growth