08-16-2009, 09:02 AM
The correct answer is B. The patient described above has Gaucher disease, a hereditary disease that affects
bones and other organs. Glucocerebrosides accumulate within macrophages in places such as bone marrow.
The failure of proper bone remodeling of the distal femur gives the characteristic "Erlenmeyer flask" shape on
x-ray. These patients suffer Gaucher crises from acute ischemia to the bone, usually in the pelvis and femoral
head. The pain is sudden, severe, and progressive, lasting 2 or more weeks before fading. The crisis usually
follows viral illness. Other findings include osteosclerotic bone and corticomedullary osteonecrosis.
Abnormal osteoclasts and mosaic lamellar bone (choice A) describe Paget disease of bone. This is a disease of
disordered bone remodeling that affects people older than 60. Although the etiology is unknown, it may be due
to viral effect on osteoclasts. The osteoclast activity is excessive, and increased absorption occurs. The
osteoclasts appear to have too many nuclei. The lamellar bone slowly acquires a mosaic pattern because of
irregular cement lines. Pain is usually due to fractures of the misshapen bone.
Benign reactive bone around an osteoid nidus (choice C) describes osteoid osteoma. This is a common lesion
that is found in young people aged 5-25 years. It is usually seen radiographically in the cortex of the diaphysis
as a small, round lesion, composed of a nidus of osteoid surrounded by woven bone. It is painful, usually at
night; the pain is relieved by aspirin. Surgery is curative.
Malignant sarcoma (choice D) would probably represent an osteosarcoma in this age and location. Clinically,
sarcomas do not present with acute pain, but rather are associated with steadily progressive pain. Radiographs
show a destructive tumor with elevated periosteum and reactive new bone formation. Treatment includes
amputation.
Well-differentiated cartilage (choice E), if located in the marrow space and not just caused by a misguided
biopsy attempt, would indicate a solitary chondroma or enchondroma. This is a benign tumor that is probably
hamartomatous in nature. It is asymptomatic and forms during development. It is sometimes found incidentally.
bones and other organs. Glucocerebrosides accumulate within macrophages in places such as bone marrow.
The failure of proper bone remodeling of the distal femur gives the characteristic "Erlenmeyer flask" shape on
x-ray. These patients suffer Gaucher crises from acute ischemia to the bone, usually in the pelvis and femoral
head. The pain is sudden, severe, and progressive, lasting 2 or more weeks before fading. The crisis usually
follows viral illness. Other findings include osteosclerotic bone and corticomedullary osteonecrosis.
Abnormal osteoclasts and mosaic lamellar bone (choice A) describe Paget disease of bone. This is a disease of
disordered bone remodeling that affects people older than 60. Although the etiology is unknown, it may be due
to viral effect on osteoclasts. The osteoclast activity is excessive, and increased absorption occurs. The
osteoclasts appear to have too many nuclei. The lamellar bone slowly acquires a mosaic pattern because of
irregular cement lines. Pain is usually due to fractures of the misshapen bone.
Benign reactive bone around an osteoid nidus (choice C) describes osteoid osteoma. This is a common lesion
that is found in young people aged 5-25 years. It is usually seen radiographically in the cortex of the diaphysis
as a small, round lesion, composed of a nidus of osteoid surrounded by woven bone. It is painful, usually at
night; the pain is relieved by aspirin. Surgery is curative.
Malignant sarcoma (choice D) would probably represent an osteosarcoma in this age and location. Clinically,
sarcomas do not present with acute pain, but rather are associated with steadily progressive pain. Radiographs
show a destructive tumor with elevated periosteum and reactive new bone formation. Treatment includes
amputation.
Well-differentiated cartilage (choice E), if located in the marrow space and not just caused by a misguided
biopsy attempt, would indicate a solitary chondroma or enchondroma. This is a benign tumor that is probably
hamartomatous in nature. It is asymptomatic and forms during development. It is sometimes found incidentally.