USMLE USMLE Certifications USMLE-STEP-3 Questions & Answers

• Question 91:

  A 67-year-old female was admitted to the hospital because of chronic fatigue and low back pain. An x-ray of the vertebral column showed diffuse osteoporosis and compression fractures of L1 and L2 vertebral bodies. The complete blood count (CBC) was within normal limits. The peripheral blood smear showed rouleaux formation. The immunoelectrophoresis showed a monoclonal spike of more than 3 g. A bone marrow biopsy was performed and showed an increase of more than 20% in plasma cells see Figure below In this particular patient what would be the electrophoretical characteristic changes?

  

  A. increases levels of IgG and light chains in the urine

  B. IgM spike

  C. IgA elevation

  D. increase in albumin

  E. polyclonal electrophoretic pattern

  Correct Answer: A Section: (none)

  Explanation:

  Multiple myeloma is a plasma cell dyscrasia that is characterized by involvement of the skeleton in multiple sites. The characteristic x-ray shows punched-out bone lesions that are very easily seen in the calvarium. Extension of the disease to lymph nodes and extranodal sites, such as skin, can be seen. The bone marrow biopsy and smears reveal an increased number of plasma cells, which usually constitute greater than 20% of all of the cells. The cells either diffusely infiltrate and replace the marrow elements or can be seen scattered throughout the hematopoietic elements. The neoplastic plasma cells have a perinuclear hof and an eccentrically placed nucleus which allows the recognition. In 99% of patients with multiple myeloma, electrophoretic analysis reveals increased levels of IgG in the blood, light chains (Bence-Jones proteins) in the urine, or both. The monoclonal IgG produces a high spike when seen in the serum or in the urine, subject to electrophoresis. In general, the quantitative analysis of the monoclonal IgG is more than 3 g. The clinicopathologic diagnosis of multiple myeloma rests on radiographic and laboratory findings. Marrow examination may reveal increased plasma cells or sheet-like aggregates that may completely replace the normal elements. The prognosis for this condition is variable, but generally poor.

• Question 92:

  A 45-year-old woman presents with a slowly growing mass near the right jaw. You palpate a firm nodule in

  the parotid gland but find no adenopathy and no other abnormality on examination. A biopsy reveals both

  epithelial and stromal elements.

  What is the appropriate treatment for this lesion?

  A. observation, as this is a benign lesion

  B. external beam radiation therapy

  C. excision with narrow margins

  D. excision with a wide margin of normal tissue

  E. chemotherapy

  Correct Answer: D Section: (none)

  Explanation:

  Pleomorphic adenoma (mixed tumor) is the most common tumor of the salivary glands. Pleomorphic adenoma is a benign neoplasm characterized by a mixture of epithelium and stromal elements. Two-thirds of all tumors of the major salivary glands and about half of those in the minor ones are pleomorphic adenomas. The tumor is nine times more frequent in the parotid than in the submandibular gland and usually arises in the superficial lobe of the parotid. It occurs most often in the middleaged people and shows a female preponderance. While it is a benign tumor, the recommended treatment is removal, as it will continue to grow and cause symptoms. Most authorities recommend wide local excisions, in an effort to reduce the risk of recurrence.

• Question 93:

  A 25-year-old female presents for evaluation of a breast mass and tenderness. She describes the breast soreness as varying with her menstrual cycles. On examination, you feel a firm, movable, irregular 2 cm mass. Her breast tissue is diffusely dense bilaterally. Of the options listed, which is the most likely?

  A. lipoma

  B. fibroadenoma

  C. hemangioma

  D. intraductal papilloma

  E. phylloides tumor, benign

  Correct Answer: B Section: (none)

  Explanation:

  Fibroadenoma is the most common benign neoplasm of the breast and is composed of two types of tissues. A mesenchymal element most commonly composed of edematous or collagenized fibrous tissue and an epithelial component, which consists of compressed, and sometimes hyperplastic, irregular ductal lumens. They are usually found in young women and may be hormonally reactive during pregnancy or menopause.

• Question 94:

  A 45-year-old woman presents with a slowly growing mass near the right jaw. You palpate a firm nodule in

  the parotid gland but find no adenopathy and no other abnormality on examination. A biopsy reveals both

  epithelial and stromal elements.

  What is this patient's diagnosis?

  A. pleomorphic adenoma (mixed tumor)

  B. Whartin tumor

  C. monomorphic adenoma

  D. basal cell adenoma

  E. oxyphilic adenoma

  Correct Answer: A Section: (none)

  Explanation:

  Pleomorphic adenoma (mixed tumor) is the most common tumor of the salivary glands. Pleomorphic adenoma is a benign neoplasm characterized by a mixture of epithelium and stromal elements. Two-thirds of all tumors of the major salivary glands and about half of those in the minor ones are pleomorphic adenomas. The tumor is nine times more frequent in the parotid than in the submandibular gland and usually arises in the superficial lobe of the parotid. It occurs most often in the middleaged people and shows a female preponderance. While it is a benign tumor, the recommended treatment is removal, as it will continue to grow and cause symptoms. Most authorities recommend wide local excisions, in an effort to reduce the risk of recurrence.

• Question 95:

  You are following up in your office with a patient who had a magnetic resonance imaging (MRI) of his head for evaluation of persistent headaches. The MRI report reveals a mass suspicious for malignancy. While explaining the need for ongoing testing to determine the etiology, the patient's spouse asks you, "What is the most common tumor in the brain?" Which of the following would be the correct response to this question?

  A. glioblastoma multiforme

  B. metastatic tumors

  C. meduloblastoma

  D. oligodendroglioma

  E. ependymoma

  Correct Answer: B Section: (none)

  Explanation:

  Metastatic tumors reach the intracranial compartment through the blood stream, generally in patients with advanced cancer. Tumors of different organs vary in their incidences of intracranial metastasis. For example, a patient with disseminated melanoma has a greater than 50% likelihood of acquiring intracranial metastasis, whereas the incidences of such metastasis in carcinoma of the breast and lungs is 35%. Certain carcinomas such as those of the prostate, liver, and adrenals and sarcomas of all types rarely establish intracranial metastasis. A metastasis contrast with the primary glioma in its discrete appearance, globoid shape, and prominent halo of edema

• Question 96:

  An autopsy is performed on an 82-year-old female diagnosed with Alzheimer disease. Which of the following is most likely to be found on evaluation of her brain?

  A. fibrosis

  B. necrosis

  C. senile plaques

  D. calcifications

  E. neuronal vacuolization

  Correct Answer: C Section: (none)

  Explanation:

  Senile plaques are the most conspicuous histologic lesion also known as neuritic plaque, constitute a spherical deposit of A fragments (amyloid beta fragments) of variant degree length. They are surrounded by reactive astrocytes, microglia, and display alpha-synuclein immunoreactive neuronal process.

• Question 97:

  A 72-year-old male presented with nonspecific symptoms of easy fatigability, weight loss, and anorexia. On physical examination, generalized lymphadenopathy and hepatosplenomegaly were present. On the peripheral blood, he was found to have a marked lymphocytosis and in the serum, a small monoclonal spike was present. This disease is most prevalent in which age group?

  A. teenagers

  B. 2030 age group

  C. 3040 age group

  D. over 50 years

  E. it may appear at any age

  Correct Answer: D Section: (none)

  Explanation:

  Chronic lymphocytic leukemia is a disease that presents generally over the age of 50 with a male predominance. For a long time many of these patients remain asymptomatic and, when they do present, the symptomatology is nonspecific, with generalized lymphadenopathy and hepatosplenomegaly. The peripheral lymphocyte count is generally high and composed of small lymphocytes. A low percentage of patients develop autoantibodies directed against red cells or platelets, which produces autoimmune hemolytic anemia or thrombocytopenia. Although the disease progresses and relapses in spite of the chemotherapy treatment, the overall median survival is 46 years, but this appears to be very variable. Some patients may survive longer than 10 years. All of the parameters for a worse prognosis have to be measured before a final statement of prognosis can be made. The lymph node architecture is diffusely effaced by a population of small lymphocytes, which contain nondiscernible cytoplasm and inconspicuous nucleoli. Mitotic activity is rare, focal proliferation centers with an increase in the number of mitotic activity cells are seen.

• Question 98:

  A 72-year-old male presented with nonspecific symptoms of easy fatigability, weight loss, and anorexia. On physical examination, generalized lymphadenopathy and hepatosplenomegaly were present. On the peripheral blood, he was found to have a marked lymphocytosis and in the serum, a small monoclonal spike was present. The clinical behavior of this disease can best be described by which of the following?

  A. rapidly progressive

  B. never relapses

  C. can be completely eradicated by chemotherapy

  D. the median survival is 46 years

  E. never responds to chemotherapeutic agents

  Correct Answer: D Section: (none)

  Explanation:

  Chronic lymphocytic leukemia is a disease that presents generally over the age of 50 with a male predominance. For a long time many of these patients remain asymptomatic and, when they do present, the symptomatology is nonspecific, with generalized lymphadenopathy and hepatosplenomegaly. The peripheral lymphocyte count is generally high and composed of small lymphocytes. A low percentage of patients develop autoantibodies directed against red cells or platelets, which produces autoimmune hemolytic anemia or thrombocytopenia. Although the disease progresses and relapses in spite of the chemotherapy treatment, the overall median survival is 46 years, but this appears to be very variable. Some patients may survive longer than 10 years. All of the parameters for a worse prognosis have to be measured before a final statement of prognosis can be made. The lymph node architecture is diffusely effaced by a population of small lymphocytes, which contain nondiscernible cytoplasm and inconspicuous nucleoli. Mitotic activity is rare, focal proliferation centers with an increase in the number of mitotic activity cells are seen.

• Question 99:

  A 72-year-old male presented with nonspecific symptoms of easy fatigability, weight loss, and anorexia. On physical examination, generalized lymphadenopathy and hepatosplenomegaly were present. On the peripheral blood, he was found to have a marked lymphocytosis and in the serum, a small monoclonal spike was present. What would be the most likely histology seen in a lymph node biopsy?

  A. reactive germinal centers

  B. diffuse effacement of the normal architecture by a small lymphocytic population

  C. diffuse architecture effacement with large cells with prominent nucleoli

  D. a pleomorphic background composed of eosinophils, plasma cells, and small lymphocytes

  E. a total replacement of the node by plasma cells

  Correct Answer: B Section: (none)

  Explanation:

  Chronic lymphocytic leukemia is a disease that presents generally over the age of 50 with a male predominance. For a long time many of these patients remain asymptomatic and, when they do present, the symptomatology is nonspecific, with generalized lymphadenopathy and hepatosplenomegaly. The peripheral lymphocyte count is generally high and composed of small lymphocytes. A low percentage of patients develop autoantibodies directed against red cells or platelets, which produces autoimmune hemolytic anemia or thrombocytopenia. Although the disease progresses and relapses in spite of the chemotherapy treatment, the overall median survival is 46 years, but this appears to be very variable. Some patients may survive longer than 10 years. All of the parameters for a worse prognosis have to be measured before a final statement of prognosis can be made. The lymph node architecture is diffusely effaced by a population of small lymphocytes, which contain nondiscernible cytoplasm and inconspicuous nucleoli. Mitotic activity is rare, focal proliferation centers with an increase in the number of mitotic activity cells are seen.

• Question 100:

  Polyarteritis nodosa (PAN) typically involves which of the following?

  A. large elastic arteries

  B. small-or medium-sized muscular arteries

  C. arterioles

  D. capillaries

  E. venules

  Correct Answer: B Section: (none)

  Explanation:

  PAN typically involves small-to mediumsized muscular arteries. In contrast, large arteries and the aorta are involved in Takayasu arteritis. Small arteries and arterioles are involved in a number of other diseases, including systemic lupus erythematosus. Active lesions in PAN demonstrate a neutrophilic infiltration of the involved vessel wall with thrombosis and segmental, fibrinoid necrosis. Intermittent healing produces fibrosis of the arterial wall and intimal thickening, which may lead to obstruction and infarction. Aneurysmal dilations may arise as a result of asymmetrical involvement. Although the lesions in PAN resemble other immunemediated vascular lesions, the exact etiology of the disorder has not been elucidated. PAN generally affects middle-aged men and has a poor prognosis, although steroids may be beneficial.