MCQ Book Questions

Q60862. A 56-year-old woman receives high-dose radiation therapy for thyroid carcinoma. One year later, the patient presents with a subcutaneous mass at the site of irradiation. A photomi- crograph of the biopsy is shown in the image. Which of the following is the most likely diagnosis?

Q60863. A 40-year-old woman presents with pain and swelling in her left elbow that has lasted 6 months. Physical examination reveals a 0.5-cm soft tissue mass. Biopsy of the mass discloses a biphasic histologic pattern consisting of cuboidal epithelial and spindle-shaped mesenchymal cells. Which of the follow- ing is the most likely diagnosis?

Q60864. A 50-year-old man complains of fever and severe pain in his great toe of 24 hours in duration. The pain developed in the morning and became so severe that he could not walk. Labora- tory fi ndings include leukocytosis, hyperuricemia, and hyper- lipidemia. An X-ray of the affected joint reveals punched-out lesions in the juxta-articular bone. An aspirate of joint fl uid returns urate crystals and neutrophils. Which of the following would be the most likely pathologic fi nding within the periar- ticular soft tissue of this patient?

Q60865. A 17-year-old boy fractures his left tibia in a skiing accident. One year later, an X-ray of the leg discloses reactive bone for- mation in the calf muscle at the site of injury. Which of the following is the most likely diagnosis?

Q60866. A 16-year-old boy presents with a 2-week history of pain in his right leg. He says that he has been taking aspirin to relieve the pain. An X-ray of the leg shows a 1-cm sharply demarcated, radiolucent lesion in the diaphysis of the tibia surrounded by dense, sclerotic bone. The lesion is surgically removed, and the gross specimen is shown in the image. Microscopically, the tumor shows irregular trabeculae of woven bone surrounded by osteoblasts, osteoclasts, and fi brovascular marrow. What is the appropriate diagnosis?

Q60867. A 68-year-old woman presents with a lump in the soft tissue of her neck. Physical examination reveals a 0.5-cm subcutane- ous tumor. Biopsy of the mass shows a benign neoplasm. The patient is told that she has the most common soft tissue tumor. What is the appropriate diagnosis?

Q60868. A 4-year-old boy is brought to the physician by his parents because he falls a lot, cannot jump, and tires easily. Physical examination reveals weakness in the pelvic and shoulder gir- dles and enlargement of the child’s calf muscles. The serum level of creatine kinase is elevated. A biopsy of calf muscle reveals marked variation in size and shape of muscle fibers. There are foci of muscle fiber necrosis, myophagocytosis, regenerating fibers, and fibrosis. Which of the following is the most likely cause of death expected in this patient?

Q60869. Molecular diagnostic assays performed on muscle biopsy from the patient described in Question 1 would show alterations in the length of the primary transcript for which of the following muscle-associated proteins?

Q60870. A 10-year-old girl complains of persistent redness of the skin over her knuckles and around the nail beds. She describes easy fatigability and can rise only with diffi culty from a squatting position. Physical examination reveals erythema over the knuckles and a heliotropic rash. A muscle biopsy shows infi ltrates of B and T lymphocytes around blood ves- sels and in connective tissue of the perimysium. Elevated serum levels of which of the following would be expected in this patient?

Q60871. A 25-year-old woman complains of weakness and easy fatigability, which is most pronounced in the late afternoon. She describes diffi culty reading and tiredness while watch- ing television. She has problems chewing and swallowing and loses her voice while talking. Physical examination reveals ptosis and diplopia. Laboratory studies would most likely demonstrate serum autoantibodies directed against which of the following proteins?

Q60872. Which of the following may be of therapeutic benefi t to the patient described in Question 4?

Q60873. A 3-month-old boy presents with severe hypotonia and arefl exia. His tongue and heart are enlarged. A muscle biopsy displays massive accumulation of membrane-bound glycogen and disappearance of the myofi laments and other sarcoplas- mic organelles. The patient dies after 1 year. Which of the following is the most likely diagnosis?

Q60874. A 42-year-old woman presents with muscle weakness. She has diffi culty climbing stairs and lately tires while combing her hair. A muscle biopsy demonstrates lymphocytic infi ltration with single-fi ber necrosis. In addition, muscle fi bers exhibit basophilic granular material. An electron micrograph of the cytoplasmic material is shown. Which of the following is the most likely diagnosis?

Q60875. A healthy 28-year-old woman collapses near the end of a sum- mer marathon. In the emergency room, the patient is noted to have hot dry skin with little sweating. Her temperature is 40.4°C (104.8°F). Laboratory fi ndings reveal high levels of creatine kinase. The urine is dark red and contains myoglobin. Which of the following would be most expected in the muscle tissue of this patient?

Q60876. A 60-year-old man who had been treated for lung cancer com- plains of a rash on his chest and pain in his upper arms and calves. He cannot raise his arms and climbs the stairs only with diffi culty. A muscle biopsy shows perivascular infi ltrates of lymphocytes and plasma cells extending in between the muscle fi bers. Immunofl uorescence reveals immune com- plexes in the walls of intramuscular blood vessels. Which of the following is the most likely diagnosis?

Q60877. A 70-year-old man who had been treated for small cell carci- noma of the lung develops marked weakness of his legs and arms. He also complained of mouth dryness, double vision, and drooping upper eyelids. On physical examination there is diffuse muscle weakness and wasting. A muscle biopsy is normal. Laboratory studies demonstrate serum IgG autoan- tibodies that recognize voltage-sensitive calcium channels in motor nerve terminals. Which of the following is the most likely diagnosis?

Q60878. A 40-year-old man presents with muscle weakness. He cannot open his hand for a handshake and cannot extend his arm after fl exing it. On physical examination, he has marked atrophy of leg and arm muscles, ptosis, and a fi xed facial expression. There is testicular atrophy. Laboratory studies demonstrate mild dia- betes. A muscle biopsy reveals atrophy of type I fi bers, hypertro- phy of type II fi bers, and numerous fi bers with centrally located nuclei. Which of the following is the most likely diagnosis?

Q60879. A 20-year-old man reports muscle cramping after vigor- ous exercise. He noted darkening of his urine after recently running a half-marathon. A urinalysis at that time showed myoglobinuria. A muscle biopsy displays no morphologic abnormalities. Which of the following is the most likely diag- nosis?

Q60880. A female neonate is noted at birth to have a gross deformity of her lower back. Examination of the subcutaneous lesion reveals disorganized neural tissue with entrapment of nerve roots. What is the appropriate diagnosis?

Q60881. The parents of the neonate described in Question 1 ask about the risks for similar birth defects in their future offspring. You mention that supplementation of the maternal diet can reduce the incidence of neural tube defects. What is this important dietary supplement?