Question 161
A clinical study is performed with subjects who have been diagnosed with a primary bone lesion. The demographic data for these subjects is analyzed. Which of the following bone diseases is most likely to be found to have a female predominance?
A Aneurysmal bone cyst
B Osteosarcoma
C Chondrosarcoma
D Ewing sarcoma
E Osteochondroma
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(A) CORRECT. Most bone lesions (and the worst ones) have a male predominance.
(B) Incorrect. Primary malignant tumors of bone have a male predominance.
(C) Incorrect. Primary malignant tumors of bone have a male predominance.
(D) Incorrect. Primary malignant tumors of bone have a male predominance.
(E) Incorrect. Primary malignant tumors of bone have a male predominance.
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Question 162
A 21-year-old college student has noted increasing pain and soreness in his left shoulder after a summer working on the ranch and bucking bales of hay (heavy lifting and turning motions) while at a ranch up in the Cache Valley. On physical examination he can hardly adduct his left arm to the level of his shoulder. An aspiration of the subacromial region is performed and clear fluid is obtained. Which of the following is the most likely diagnosis?
A Tenosynovitis
B Costochondritis
C Bursitis
D Ganglion cyst
E Pseudogout
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(C) CORRECT. Synovial-lined bursal sacs become inflamed and distended with watery fluid, more often in males engaging in excessive manual labor or exercise.
(A) Incorrect. Inflammation of the tendon sheath is more common in the wrists and hands.
(B) Incorrect. Costochondral junctions of ribs are present in the anterior chest.
(D) Incorrect. These cysts in the connective tissue of a tendon sheath or joint capsule are usually seen in the wrist.
(E) Incorrect. Deposition of calcium pyrophosphate crystals in pseudogout is more typical of persons over age 50 and usually involves the knee.
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Question 163
Over the past 4 days, an 18-year-old man has developed marked pain and swelling in his right hip that makes movement difficult. He has no history of major medical problems. On physical examination there is pain on movement with diminished range of motion of the hip. A joint aspirate from the hip reveals cloudy fluid that on microscopic examination shows numerous neutrophils but no crystals. Which of the following conditions is most likely to have preceded development of his hip problem?
A Gonococcal urethritis
B Sickle cell anemia
C Rheumatoid arthritis
D Systemic lupus erythematosus
E Erythema chronicum migrans
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(A) CORRECT. Neisseria gonorrheae infection can produce an acute arthritis. A gram stain of a joint aspirate may show many neutrophils with intracellular gram-negative diplococci.
(B) Incorrect. Sickle cell anemia may be associated with osteomyelitis due to Salmonella organisms, but this is rare.
(C) Incorrect. Small joints (such as the hand) are more likely to be involved than large joints (such as the hip) with rheumatoid arthritis. There is proliferative synovitis with lymphocytes and plasma cells.
(D) Incorrect. Autoimmune diseases such as systemic lupus erythematosus are often associated with arthralgias, but there is minimal actual joint inflammation and typically no deformity.
(E) Incorrect. The arthritis of Lyme disease is often seen in stages II or III and is not typically purulent.
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Question 164
A social worker refers a 2-year-old child to the physician because of suspected child abuse. On physical examination, the child has blue sclerae, diminished hearing in both ears, and misshapen teeth. There are no external contusions or lacerations of the skin. Radiographs of the child's extremities show recent and healing long bone fractures. Which of the following is the most likely diagnosis?
A Extensive trauma ("shaken child syndrome")
B Osteogenesis imperfecta
C Achondroplasia
D Rickets
E Osteopetrosis
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(B) CORRECT. This is a disorder of type 1 collagen synthesis, with subsequent risk for fractures of bone. The blue sclerae, hearing loss, and dental abnormalities are characteristic for OI.
(A) Incorrect. Don't make the mistake of assuming all fractures are due to trauma.
(C) Incorrect. Achondroplasia is a form of dwarfism, but it is not characterized by fractures.
(D) Incorrect. The bones in a growing child with rickets will be deformed, but extensive fractures are not common.
(E) Incorrect. This rare condition (Albers-Schonberg disease) is a hereditary defect in osteoclast function with markedly thickened, sclerotic bone that fractures readily.
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Question 165
A 23-year-old G2 P1 woman has noted minimal fetal movement at 18 weeks gestation. An ultrasound scan shows that the fetal limbs are shortened. At 30 weeks gestation a stillborn fetus is delivered. A postmortem radiograph reveals extensive long bone, rib, and pelvic fractures. Autopsy reveals a normal appearance to internal organs. A mutation involving a gene encoding for which of the following proteins is most likely to produce these findings?
A Fibrillin
B Fibroblast growth factor receptor 3
C Retinoblastoma
D Neurofibromin
E Type I collagen
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(E) CORRECT. Osteogenesis imperfecta is an inherited disorder (usually autosomal recessive) of type I collagen synthesis. This is OI type II, the perinatal lethal form..
(A) Incorrect. Mutations of the fibrillin gene are present with Marfan syndrome, which affects the connective tissue of the cardiovascular system most severely.
(B) Incorrect. The FGFR gene mutations are associated with skeletal dysplasias, such as achondroplasia, that are not usually accompanied by fractures.
(C) Incorrect. The Rb gene is a tumor suppressor gene. If both copies of the gene are mutated, then the risk for malignancy is increased. One of the malignancies that can occur is osteosarcoma.
(D) Incorrect. NF1 can be associated with bone deformities beginning in childhood as a consequence of growth of neurofibromas.
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Question 166
A 41-year-old previously healthy man has had backache with muscle spasms, weakness, and pain felt in the right hip radiating all the way to his toes for the past 8 months. He does not have headaches or other neurologic problems. Physical examination reveals that the circumference of his right leg is smaller than the left, and he has paresthesias in an L5 distribution in the right leg. Which of the following conditions is he most likely to have?
A Spondylolisthesis
B Spina bifida
C Herniated nucleus pulposus
D Osteoporosis
E Paget disease of bone
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(C) CORRECT. He has a herniated intervertebral disk in which impingement on spinal nerve roots (usually L5 or S1) produces sensory and motor disturbances.
(A) Incorrect. In this disorder, the vertebral body, pedicles, and facets 'slips' forward to produce back pain, and limited motion. Symptoms are often bilateral.
(B) Incorrect. This is a failure of fusion of the laminae of the neural arch and is usually occult until an injury or radiograph reveals it.
(D) Incorrect. Osteoporosis at his age and in a male is unlikely. Compressed vertebral fractures may involve nerve roots, but are not as likely as a herniated disk.
(E) Incorrect. This is unlikely at his age. Paget is often painless, but if advanced, a nerve root may become entrapped.
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Question 167
A 5-year-old child has complained of pain on the left side of his head for 3 weeks. There are no abnormal findings on physical examination. A skull radiograph reveals a solitary destructive bony lesion of the left mastoid region. A biopsy is performed and microscopic examination shows that this lesion is composed histologically of a mixed inflammatory cell infiltrate. Which of the following is the most likely diagnosis?
A Osteoid osteoma
B Letterer-Siwe syndrome
C Eosinophilic granuloma
D Osteitis fibrosa cystica
E Tuberculosis
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(C) CORRECT. Eosinophilic granulomas are a localized form of Langerhans cell histiocytosis that can be found in skull or long bones and can mimic osteomyelitis. The mixed inflammatory cell infiltrated can have histiocytes, eosinophils, plasma cells, and lymphocytes.
(A) Incorrect. This lesion has a central nidus surrounded by sclerotic bone.
(B) Incorrect. This disseminated form of Langerhans cell histiocytosis most often occurs in children under 3.
(D) Incorrect. This localized bone lesion occurs most often in patients with hyperparathyroidism.
(E) Incorrect. Epithelioid macrophages and Langhans giant cells should be present in a granuloma with M. tuberculosis.
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Question 168
A 49-year-old man has complained of episodes of joint pain for over 10 years. This pain has occurred in a remitting and relapsing pattern. On physical examination there are deformities of his hands involving the fingers, with swan-neck deformities and ulnar deviation. His condition improves following corticosteroid and gold therapy. Which of the following serologic tests is most likely to be positive in this man?
A Rapid plasma reagin
B HLA-B27
C Anti-double stranded DNA
D Rheumatoid factor
E Borrelia burgdorferi
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(D) CORRECT. Joint deformity frequently occurs with chronic rheumatoid arthritis. Females are affected more than males, and pregnancy may lessen the severity of the disease. However, men can get RA.
(A) Incorrect. The RPR is a screening test for syphilis. Gummatous necrosis in tertiary syphilis may involve large joints such as the knees..
(B) Incorrect. HLA-B27 is often positive in ankylosing spondylitis which involves the spine.
(C) Incorrect. The anti-double stranded DNA positivity is most specific for systemic lupus erythematosus, which is unlikely to be complicated by joint deformity.
(E) Incorrect. Ankylosis can and does occur often with severe rheumatoid arthritis.
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Question 169
An 11-year-old boy has complained of pain in the region of the right upper thigh for 2 weeks. This pain is worse at night and is relieved by aspirin. On physical examination no abnormal findings are noted. A radiograph of his right leg reveals a small lucent area in the proximal femoral cortex surrounded by sclerotic bone. Which of the following is the most likely diagnosis?
A Enchondroma
B Multiple myeloma
C Eosinophilic granuloma
D Osteoid osteoma
E Osteochondroma
F Ewing sarcoma
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(D) CORRECT. There is a central nidus with surrounding sclerotic bone. They are very painful from release of prostaglandins.
(A) Incorrect. Though an enchondroma occurs within bone, there is not a radiolucent nidus.
(B) Incorrect. This is a lesion filled with plasma cells and seen in older adults.
(C) Incorrect. This lesion has a variety of inflammatory cells, including eosinophils and usually does not have surrounding sclerotic bone.
(E) Incorrect. This lesion usually produces a lateral projection from the bony cortex.
(F) Incorrect. A Ewing sarcoma is unlikely to be so localized as this, and pain from a malignancy is unlikely to be relieved by aspirin.
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Question 170
A 69-year-old man has experienced a 5 kg weight loss in the past two months without dieting. He is a non-smoker. During the past 3 weeks he has had extensive bone pain in his back and extremities. On physical examination the range of motion of his extremities is normal. His stool is negative for occult blood. A radiograph of the spine shows focal vertebral masses with increased brightness. A nuclear medicine scan reveals focal areas of increased uptake ("hot spots") in the pelvis, vertebrae, and ribs. Laboratory studies show a serum alkaline phosphatase of 281 U/L. A urinalysis is normal. Which of the following neoplasms is he most likely to have?
A Adenocarcinoma of colon
B Oat cell carcinoma of lung
C Infiltrating ductal carcinoma of breast
D Renal cell carcinoma
E Adenocarcinoma of prostate
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(E) CORRECT. Prostate adenocarcinomas often produce osteoblastic metastases. They are one of the most common malignancies in older men.
(A) Incorrect. Colonic adenocarcinomas metastasize to bone infrequently. Many colon cancers bleed to produce a positive stool occult blood test.
(B) Incorrect. Oat cell (small cell anaplastic) carcinomas of lung often metastasize widely, particularly to bone, but are almost exclusive to smokers.
(C) Incorrect. Breast cancers are known for their propensity to bone metastasis. Breast cancers are rare in men.
(D) Incorrect. Renal cell carcinomas can produce osteolytic metastases. In the absence of hematuria, a large renal cell carcinoma capable of metastases is unlikely.
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