62 - orthopedics mcqs - 171 to 180 - bone pathology

Question 171

A 49-year-old woman has noted increasing difficulty with movement of her left hand for the past 2 years. On examination she cannot completely extend the left middle finger. In the palm of her hand at the base of this finger there is an ill-defined mass that is very firm to palpation. What will microscopic examination of this excised mass most likely show?

A Fibromatosis

B Rhabdomyosarcoma

C Granulomatous inflammation

D Dystrophic calcification

E Giant cell tumor of tendon sheath

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(A) CORRECT. This is a so-called Dupuytren contracture due to a palmar fibromatosis. The etiology is obscure.

(B) Incorrect. In adults, these tumors are uncommon and appear as large masses in deep soft tissues.
(C) Incorrect. A foreign body granuloma could occur at this site, but would not likely lead to a contracture of one finger.
(D) Incorrect. This would not lead to a marked contracture.
(E) Incorrect. This appears as a more well-circumscribed mass without contracture.

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Question 172

A 45-year-old woman notices that she develops tingling and numbness over the palmar surface of her thumb, index, and middle fingers after several hours at her computer workstation doing word processing. Pain in the same area often occurs at night as well. On physical examination she has minimal atrophy of thenar muscles of both hands. Which of the following conditions is most likely to account for her symptoms?

A Toxic peripheral neuropathy

B Rheumatoid arthritis

C Gout

D Hypertrophic osteoarthropathy

E Diabetes mellitus

F Localized tenosynovitis

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(F) CORRECT. She has carpal tunnel syndrome, an entrapment neuropathy of the median nerve. In middle-aged women, tenosynovitis is often present, worsened by repetitive motion.

(A) Incorrect. The neuropathy she has is too localized to suggest a toxic etiology.
(B) Incorrect. Rheumatoid arthritis leads to pain, but not in a localized area in median nerve distribution.
(C) Incorrect. Gout may lead to tophaceous deposits, but over bony prominences, not median nerve.
(D) Incorrect. Hypertrophic osteoarthropathy is characterized by clubbing of the digits as well as arthritis. It is most often associated with cardiorespiratory diseases such as chronic obstructive pulmonary disease.
(E) Incorrect. Though diabetes mellitus may result in peripheral neuropathy, such a diabetic neuropathy is unlikely to be so localized as in this case, and unlikely to be related to repetitive motion.

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Question 173

A 55-year-old woman has a 15 year history of poorly controlled diabetes mellitus. She develops increasing bone pain in her extremities over the past 4 months. On physical examination there are no abnormal findings. A radiograph of the hand shows osteitis fibrosa cystica of the metacarpals. Laboratory studies show a serum urea nitrogen of 65 mg/dL and serum creatinine of 7.0 mg/dL. Which of the following pathologic abnormalities is she most likely to have?

A Chondrocalcinosis

B Hyperparathyroidism

C Multiple myeloma

D Osteochondromatosis

E Osteopetrosis

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(B) CORRECT. In secondary hyperparathyroidism, the parathyroid glands are hyperplastic. The renal failure impairs renal phosphate excretion, leading to hyperphosphatemia, which depresses the serum calcium and turns on parathyroid hormone production, leading to renal osteodystrophy.

(A) Incorrect. Chondrocalcinosis affecting joints is not related to diabetes mellitus or renal failure.
(C) Incorrect. Multiple myeloma may produce renal failure. The bone lesions are characteristically lytic.
(D) Incorrect. Osteochondromatosis leads to multiple bony exostoses; it is unrelated to diabetes mellitus or renal failure.
(E) Incorrect. Osteopetrosis is rare and unlikely to occur with chronic renal failure or diabetes mellitus.

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Question 174

A 45-year-old man has noted pain in his right knee for the past 5 years. As he moves about during the day, the pain decreases. On physical examination there is no joint swelling, warmth, or erythema, but he does have decreased range of motion. Which of the following conditions is he most likely to have?

A Osteoporosis

B Osteochondroma

C Osteomalacia

D Osteoarthritis

E Osteopetrosis

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(D) CORRECT. Osteoarthritis often involves a larger, weight-bearing joint. The pain usually diminishes with movement, but recurs with reuse or prolonged use of the affected joint.

(A) Incorrect. Osteoporosis would be uncommon in a 45-year-old man. Back pain is a more typical symptom for osteoporosis.
(B) Incorrect. This mass lesion could be located about the knee, but the pain would probably be exacerbated by movement or local trauma.
(C) Incorrect. The findings with osteomalacia would be similar to osteoporosis, and back pain would be more typical.
(E) Incorrect. This uncommon inherited metabolic disorder leads to 'brittle bones' that predispose to fractures.

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Question 175

As he continues to age, a 50-year-old man is bothered by slowly progressive loss of mobility of his spine at the hips since the age of 25. He has a brother who is similarly affected. On physical examination there is loss of lumbar lordosis with decreased range of motion at his hips. Which of the following pathologic abnormalities involving his sacroiliac joints is most likely to be present?

A Ankylosis

B Gummatous necrosis

C Mosaic growth pattern

D Osteonecrosis

E Pannus formation

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(A) CORRECT. The hereditary nature of ankylosing spondylitis means that about one-fourth of close relatives have the disease. Bony ankylosis of the sacroiliac joint is a common outcome in a patient who has had ankylosing spondylitis for years.

(B) Incorrect. Gummatous necrosis is a feature of tertiary syphilitic involvement of bone, which is most often knees.
(C) Incorrect. A mosaic pattern of osteolysis and osteosclerosis is characteristic for Paget disease of bone, which is more common in older persons and does not have a hereditary pattern.
(D) Incorrect. Osteonecrosis can be seen with ischemia and infection.
(E) Incorrect. Pannus formation is characteristic for rheumatoid arthritis, which most often affects the small joints of hands and feet first.

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Question 176

A 10-year-old girl has complained of joint pain for the past 2 years. The pain is localized to her knees and ankles; it occurs either with or without movement. The arthralgias are accompanied by fever. On physical examination she has a temperature of 37.8 C. There is no deformity of her knees. She has generalized lymphadenopathy. Which of the following is the most likely diagnosis?

A Gonococcal arthritis

B Ankylosing spondylitis

C Juvenile rheumatoid arthritis

D Tuberculous arthritis

E Gout

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(C) CORRECT. Also known as Still disease, JRA is not frequent. About 5% of rheumatoid arthritis cases occur in persons <16>

(A) Incorrect. Gonococcal arthritis is a suppurative arthritis, and it is seen most often in young persons as a complication of gonorrheal infection.
(B) Incorrect. Ankylosing spondylitis typically involves the spine. It is slowly progressive, beginning in the 3rd decade, and does not have a febrile component or lymphadenopathy.
(D) Incorrect. Tuberculous arthritis is a complication of adjacent osteomyelitis or dissemination. It is destructive and monoarticular, usually involving the spine.
(E) Incorrect. Gouty arthritis usually involves the big toe of males with hyperuricemia who are past the third decade.

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Question 177

A pathologic study is performed involving patients with a history of arthritis. These patients had femoral heads submitted to surgical pathology following resection and placement of hip prostheses. The pathologic findings observed by microscopic examination of these specimens are analyzed. Which of the following findings is most likely to be seen with the greatest frequency in these patients?

A Loss of articular hyaline cartilage

B Synovitis

C Underlying osteomyelitis of bone

D Bone marrow fibrosis

E Crystal deposition

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(A) CORRECT. Osteoarthritis is very common. The articular surface becomes worn or damaged with time, leading to pain and loss of mobility

(B) Incorrect. Chronic inflammation is more a feature of rheumatoid arthritis, which is less common than osteoarthritis.
(C) Incorrect. Osteomyelitis is not frequent and arthritis is not a common association.
(D) Incorrect. Although fibrosis of adjacent marrow beneath the articular cartilage may occur, it is of no major importance -- most hematopoiesis is in vertebra, ribs and sternum.
(E) Incorrect. Gouty arthritis with sodium urate deposition and 'pseudogout' with calcium pyrophosphate deposition are not nearly as common as osteoarthritis.


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Question 178

An epidemiologic study is performed with data entered into the hospital tumor registry for subjects who were diagnosed with bone tumors. Which of the following primary neoplasms of bone is most likely to be present in an older adult, rather than in a child or young adult?

A Osteosarcoma

B Chondrosarcoma

C Ewing sarcoma

D Giant cell tumor

E Osteoid osteoma

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(B) CORRECT. Chondrosarcomas occur over a wide age range. Many arise in older adults. The 'secondary' forms that follow enchondromatosis appear later in life.

(A) Incorrect. Osteosarcomas are more likely to appear in the first to third decades of life. Some, however, are 'secondary' and appear in older persons with Paget disease of bone.
(C) Incorrect. Ewing sarcomas usually occur in the first two decades of life.
(D) Incorrect. Most giant cell tumors occur in women between the ages of 20 and 40.
(E) Incorrect. This painful lesion appears in the first three decades of life, more often in males.

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Question 179

A 71-year-old man dies from pneumonia. Laboratory studies prior to death showed a serum alkaline phosphatase of 289 U/L, total protein 6.0 g/dL, albumin 3.8 g/dL, calcium 12.9 mg/dL, and phosphorus 3.6 mg/dL. At autopsy multiple firm white irregular mass lesions are scattered throughout his vertebrae. Which of the following is the most likely diagnosis?

A Metastatic carcinoma of prostate

B Osteochondromatosis

C Ewing sarcoma

D Fibrous dysplasia of bone

E Osteomalacia

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(A) CORRECT. An elevated serum alkaline phosphatase in an older adult is a red flag for metastatic carcinoma to bone.

(B) Incorrect. Osteochondromatosis is rare. Osteochondromas are exostoses of bone.
(C) Incorrect. Ewing sarcoma is seen in children and young adults, typically in the diaphyseal region of long bones.
(D) Incorrect. Fibrous dysplasia is uncommon disorder of bone maturation that leads to bone deformity with fracture.
(E) Incorrect. Vitamin D deficiency in adults can lead to decreased bone mineralization with an appearance similar to osteoporosis.

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Question 180

A 30-year-old man has pain about his left knee that he says has been worsening "for weeks". On physical examination the left knee appears larger than the right, and there is tenderness to palpaption. A radiograph reveals a 7 cm lytic lesion involving the epiphyseal region of the distal femur with a "soap bubble" appearance. The lesion is curretted, and histologically there are numerous multinucleated cells in a stroma with plump to spindle shaped mononuclear cells. Which of the following is the most likely diagnosis?

A Osteosarcoma

B Chondrosarcoma

C Malignant fibrous histiocytoma

D Giant cell tumor

E Tuberculosis

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(D) CORRECT. A giant cell tumor of bone typically arises in the epiphysis.

(A) Incorrect. Osteosarcoma is usually seen in the metaphyseal region and destroys cortex of bone. Very atypical cells with osteoid production are seen microscopically.
(B) Incorrect. Chondrosarcomas have atypical chondrocytes with cartilagenous matrix. They often form a bulky mass without distinct borders.
(C) Incorrect. An MFH is a sarcoma that may arise in bone and lead to destruction with erosion of bone.
(E) Incorrect. Tuberculosis leads to a chronic osteomyelitis with bone destruction and remodelling.