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10. Pathology and Oncology MCQs

Practice Set 84 of 351

This practice set contains high-yield board review questions covering key concepts in 10. Pathology and Oncology. Each clinical scenario is designed to test your diagnostic and management skills relevant to this subspecialty.

Question 1661

Topic: Bone Tumors

-A 14-year-old girl has a painless deformity of the right tibia. A radiograph from 2 years ago is seen in Figure a; nothing was done at that time. Her current radiograph is seen in Figure b. She has no pain, fever, or drainage. What is the most likely diagnosis?

. Adamantinoma
. Fibrous dysplasia
. Osteofibrous dysplasia
. Nonossifying fibroma
. Chronic osteomyelitis

Correct Answer & Explanation

. Adamantinoma

Explanation

Question 1662

Topic: 10. Pathology and Oncology
Exostoses in which of the following anatomic locations is the most likely to undergo malignant transformation in a patient with multiple hereditary exostosis (MHE)?
. Distal humerus
. Distal radius
. Distal femur
. Lumbar spine
. Scapula

Correct Answer & Explanation

. Scapula

Explanation

DISCUSSION: Although osteochondromas can occur in almost every bone in patients with MHE, proximally located lesions are more likely to undergo malignant transformation. Annual radiographs of the shoulder girdles and pelvis are indicated in patients with MHE. Any enlarging osteochondromas are a concern as possible malignancies. REFERENCES: Peterson HA: Multiple hereditary osteochondromata. Clin Orthop 1989;239:222. McCornack EB: The surgical management of hereditary multiple exostosis. Orthop Rev 1981;10:57.

Question 1663

Topic: 10. Pathology and Oncology
A 62-year-old woman has back pain and right L2 radicular pain. MRI scans suggest a neoplastic lesion at L2, and a bone scan is negative except at L2. History reveals that she was treated for breast cancer without known metastatic disease 12 years ago and is thought to be free of disease. What is the next most appropriate step in management?
. CT-guided biopsy
. Anterior intralesional corpectomy and fusion
. Anteroposterior fusion with en bloc resection
. Radiation therapy
. Repeat MRI in 3 months

Correct Answer & Explanation

. CT-guided biopsy

Explanation

DISCUSSION: Because of the long disease-free interval, it cannot be assumed that this is breast cancer. The lesion could represent metastasis from a new primary tumor or could itself be a primary tumor. CT-guided biopsy will most effectively identify the lesion and guide treatment options. Depending on the specific diagnosis, any of the other options may be appropriate. REFERENCE: Fardin DF, Garfin SR, Abitbol J, et al (eds): Orthopaedic Knowledge Update: Spine 2. Rosemont, IL, American Academy of Orthopaedic Surgeons, 2002, pp 411-430.

Question 1664

Topic: 10. Pathology and Oncology
A 33-year-old man reports an enlarging painful soft-tissue mass in his right forearm. A radiograph and MRI scans are shown in Figures 45a through 45c. Treatment should consist of:
. core biopsy.
. wide resection.
. radiation therapy.
. marginal resection.
. incisional biopsy.

Correct Answer & Explanation

. marginal resection.

Explanation

DISCUSSION: An intramuscular lipoma is a benign soft-tissue lesion that can grow and has a small risk of progressing to a liposarcoma. Radiographs usually show a globular radiolucent mass adjacent to higher-density muscle tissue shadows. When the patient has symptoms and reports an increase in size of the mass, the treatment of choice after appropriate radiographic analysis is complete excision of the mass with marginal resection. Sampling error is a problem with fatty lesions and core or incisional biopsies are frequently unnecessary, especially if an MRI scan of the lesion shows signal intensity that matches subcutaneous fat on all sequences. REFERENCES: Damron TA: What to do with deep lipomatous tumors. Instr Course Lect 2004;53:651-655. Gaskin CM, Helms CA: Lipomas, lipoma variants, and well-differentiated liposarcomas (atypical lipomas): Results of MRI evaluations of 126 consecutive fatty masses. Am J Roentgenol 2004;182:733-739. Rozental TD, Khoury LD, Donthineni-Rao R, et al: Atypical lipomatous masses of the extremities: Outcome of surgical treatment. Clin Orthop Relat Res 2002;398:203-211.

Question 1665

Topic: Bone Tumors
A 23-year-old man has had right posterolateral knee pain and occasional lateral calf dysesthesias for the past 8 months. A radiograph, CT scan, MRI scans, and a biopsy specimen are shown in Figures 62a through 62e. What is the most likely diagnosis?
. Osteoid osteoma
. Brodie’s abscess
. Osteoblastoma
. Chondroblastoma
. Osteosarcoma

Correct Answer & Explanation

. Osteoid osteoma

Explanation

The radiograph shows an eccentric, cortically based lytic lesion in the proximal fibula. The CT and MRI scans confirm that it is well-circumscribed and cortically based with significant surrounding edema. The radiographic differential diagnosis would be a Brodie’s abscess or osteoid osteoma. An osteoblastoma would have to be greater than 2 cm in size. A chondroblastoma may also have significant edema around it, but it is an epiphyseal-based lesion, not cortically based. The pathology shows a very cellular and vascular stroma with plump, but not atypical osteoblast cells making a matrix of immature woven bone. Therefore, the clinical and histologic picture is most consistent with an osteoid osteoma.

Question 1666

Topic: 10. Pathology and Oncology

The MRI scan of a patient with symptomatic shoulder pain reveals subacromial bursitis. What markers have been shown to be significant contributors to this pain? Review Topic

. Metalloproteases
. Alpha fetoprotein
. Prostate-specific antigen (PSA)
. Carcinoembryonic antigen (CEA)
. CA-125

Correct Answer & Explanation

. Metalloproteases

Explanation

Several inflammatory markers have been shown to be elevated in subacromial bursitis. These include metalloproteases, tumor necrosis factors, and cyclooxygenase 1 and 2. The other answers provided are all tumor markers and not typically present in routine subacromial bursitis ("impingement syndrome").

Question 1667

Topic: Bone Tumors
A 22-year-old man has mild hip pain bilaterally and multiple skeletal lesions. Based on the pelvic radiograph shown in Figure 30, what is the inheritance pattern for his disorder?
. X-linked
. Autosomal recessive
. Autosomal dominant
. Mitochondrial inheritance
. Germline mutation

Correct Answer & Explanation

. Autosomal dominant

Explanation

DISCUSSION: Multiple hereditary exostoses (MHE) is an autosomal dominant disorder manifested by multiple osteochondromas and characteristic skeletal involvement. EXT1 on 8q24.1 and EXT2 on 11p13 are the two genes most strongly associated with MHE. Mutations in these genes affect proper development of endochondral bone, such that in all affected individuals exostoses develop adjacent to the growth plates of long bones, and some exhibit additional bone deformities. Defects in the EXT genes result in increased chondrocyte proliferation and delayed hypertrophic differentiation.

Question 1668

Topic: 10. Pathology and Oncology
An infant is born with a mass that involves both the volar and dorsal compartments of the left arm. A clinical photograph and biopsy specimen are shown in Figures 41a and 41b. What is the best initial course of action?
. Debulking
. Wide resection with vascular and nerve grafting
. Above-elbow amputation
. Chemotherapy
. Radiation therapy

Correct Answer & Explanation

. Chemotherapy

Explanation

The patient has infantile fibrosarcoma. For unresectable lesions, the treatment of choice is chemotherapy with vincristine, actinomycin-D, and cyclophosphamide, followed by excision if there is an adequate decrease in the size of the lesion.

Question 1669

Topic: 10. Pathology and Oncology
A 45-year-old woman has had right wrist pain for the past 2 months. A radiograph, bone scan, and MRI scan are shown in Figures 66a through 66c, and a photomicrograph is shown in Figure 66d. What is the most likely diagnosis?
. Osteomyelitis
. Giant cell tumor
. Osteosarcoma
. Chondroblastoma
. Histiocytosis

Correct Answer & Explanation

. Giant cell tumor

Explanation

The radiograph shows a purely radiolucent lesion without matrix mineralization in the epiphysis of the distal radius. The lesion is hot on bone scan, and the MRI scan reveals cortical destruction with a soft-tissue mass. These findings are most consistent with giant cell tumor. The distal radius is a common location for giant cell tumors. The photomicrograph demonstrates multinucleated giant cells in a sea of mononuclear cells. The nuclei of the giant cells and the nuclei of the mononuclear stromal cells are identical.

Question 1670

Topic: 10. Pathology and Oncology

-Figures 14a through 14d are the radiographs and sagittal T1- and T2-weighted MRI scans of an otherwise healthy 10-year-old girl who has experienced 3 weeks of worsening pain with weight bearing and is now refusing to bear weight to either of her lower extremities. She denies any history of injury or trauma.She has not had any fevers or recent illnesses. She denies any numbness or parasthesias. She has had no bowel or bladder incontinence. In the emergency department she is afebrile and tender to palpation over the midlumbar spine. She has pain with hyperextension and flexion of her back. Her white blood cell count is 11.4 (reference range, 4.5-11.0 x109/L), erythrocyte sedimentation rate is 40 mm/h (reference range, 0-20 mm/h), and C-reactive protein is 2.6 mg/L (reference range, 0.08-3.1 mg/L). What is the most appropriate course of action at this time?

. Admission and traction
. Open surgical debridement of the lesion
. Perform an open biopsy of the lesion
. Nonsurgical treatment with antibiotics and immobilizationDISCUSSION -Childhood diskitis represents one end of a continuum of spinal infections, from diskitis to vertebral osteomyelitis with soft-tissue abscess. Diskitis is now generally accepted as a bacterial infection involving the disk space and adjacent vertebral end plates. Optimal treatment includes the use of antibiotics. Empiric coverage is directed againstStaphylococcus aureusbecause it has been the most common organism isolated from culture-positive biopsy specimens. Open biopsy is not necessary for patients who exhibit all of these clinical characteristics, but it is indicated for those whose symptoms do not resolve rapidly with treatment or who have atypical presentation.

Correct Answer & Explanation

. Admission and traction

Explanation

Question 1671

Topic: 10. Pathology and Oncology
The use of radiation therapy is most effective in metastatic bone disease from which of the following tumors?
. Renal cell carcinoma
. Adenocarcinoma of the lung
. Adenocarcinoma of the colon
. Carcinoma of the cervix
. Lymphoma

Correct Answer & Explanation

. Lymphoma

Explanation

DISCUSSION: Both myeloma and lymphoma are more responsive to radiation therapy. The other types of tumors are relatively more resistant to radiation. Doses of 25 to 50 Gy (2,500 to 5,000 cGy) are usually sufficient for myeloma and lymphoma, while carcinomas frequently require a higher dosage. Large cell lymphoma of bone is usually of B-cell origin and is treated with chemotherapy and radiation therapy.

Question 1672

Topic: 10. Pathology and Oncology
What is the most appropriate next treatment step?
. Open biopsy
. Extension casting
. CT scan of the chest
. Blood culture and image-guided needle biopsy or aspiration

Correct Answer & Explanation

. Blood culture and image-guided needle biopsy or aspiration

Explanation

DISCUSSION: Based on the patient’s signs and symptoms, the most likely diagnosis is osteomyelitis of the spine. The imaging studies do not reveal a herniated disk, which would be unusual in someone of this age. Aneurysmal bone cysts would involve the posterior elements with a more expansive lesion of bone, whereas this lesion involves primarily the body and anterior column. Hemangioma would likely not be present with systemic signs or symptoms and has a more characteristic coarse trabecular pattern on radiographs and scans. Given the likelihood that this patient has osteomyelitis of the spine, blood cultures may yield an organism about 50% of the time. If cultures are negative, an image-guided biopsy is warranted. A diagnosis needs to be established before treatment such as extension casting or bracing is rendered. Open biopsy may still be needed if needle biopsy is not diagnostic, but this is not the first treatment option. A chest CT scan is not appropriate as a first step when a tumor is presumed and a diagnosis has not been established.

Question 1673

Topic: Bone Tumors
What percent of patients initially diagnosed with classic, high-grade osteosarcoma of the extremity have visible evidence of pulmonary metastasis on CT of the chest?
. 5% to 10%
. 10% to 20%
. 40% to 50%
. 60% to 80%
. 80% to 90%

Correct Answer & Explanation

. 10% to 20%

Explanation

CT studies show that approximately 10% to 20% of patients with high-grade osteosarcoma have pulmonary metastases at diagnosis. Although not visible on current staging studies, it is believed that up to 80% of patients have micrometastatic disease that requires systemic chemotherapy.

Question 1674

Topic: 10. Pathology and Oncology
Which of the following types of osteosarcoma is associated with the best prognosis and long survival?
. Parosteal
. Periosteal
. High-grade intramedullary
. Osteosarcoma occurring in Paget’s disease
. Osteosarcoma occurring in irradiated bone

Correct Answer & Explanation

. Parosteal

Explanation

Early adequate treatment of parosteal osteosarcoma should lead to cure in most patients. A long-term survival rate of 80%-90% is to be expected for patients who have parosteal osteosarcomas without dedifferentiation. In contrast, osteosarcoma in Paget’s disease and irradiated bone have poor prognoses.

Question 1675

Topic: 10. Pathology and Oncology
The biopsy specimens seen in Figures 55a and 55b are from a lytic lesion in the sacrum of a 58-year-old man. What is the most likely diagnosis?
. Chondrosarcoma
. Metastatic renal cell carcinoma
. Chondromyxoid fibroma
. Chordoma
. Giant cell tumor

Correct Answer & Explanation

. Chordoma

Explanation

The lesion is a chordoma and the other listed choices can be eliminated based on the histology. Many tumors can occur in the sacrum including chordoma, multiple myeloma, giant cell tumor, aneurysmal bone cyst, and metastatic disease. The histology in this patient shows a lobulated lesion on low power with fibrous septae separating the lobules. At higher magnification, the cells have eosinophilic vacuolated cytoplasm and are called physaliferous cells. Chordoma is a low-grade neoplasm that most commonly occurs in the sacrum and rarely in the base of the skull. The diagnosis is often delayed. Chordoma is thought to originate from notochordal remnants. Chordoma typically occurs in the midline and has an associated soft-tissue mass.

Question 1676

Topic: 10. Pathology and Oncology
A 10-year-old boy has had thigh pain for the past several months. He denies any history of trauma. Examination reveals no soft-tissue mass, and mild tenderness. Figures 33a and 33b show the plain radiograph and MRI scan, and the biopsy specimens are shown in Figures 33c and 33d. What is the most likely diagnosis?
. Osteomyelitis
. Eosinophilic granuloma
. Osteosarcoma
. Ewing’s sarcoma
. Lymphoma of bone

Correct Answer & Explanation

. Eosinophilic granuloma

Explanation

The diagnosis is eosinophilic granuloma. The plain radiograph and MRI scan show a lesion in the midshaft of the femur. There is no soft-tissue mass. There is reactive bone about the lesion that suggests a less aggressive tumor. The histology reveals eosinophils in an otherwise bland cellular background with no evidence of mitotic figures or malignant cells to suggest sarcoma. The diagnostic elements are the amphophilic (i.e., pale purple) histiocytes with cigar-shaped nuclei, some of which have linear longitudinal grooves. There is no histologic evidence of infection. Lymphoma of bone would be an unusual occurrence in this age group, and the histology is not consistent with that diagnosis.

Question 1677

Topic: 10. Pathology and Oncology
Figures 1a and 1b show the sagittal T2- and T1-weighted MRI scans of a 25-year-old intravenous drug abuser who has low back pain that is increasing in intensity. Laboratory studies show a WBC count of 10,000/mm³ and an erythrocyte sedimentation rate of 80 mm/h. Blood culture is negative. Initial management should consist of
. CT-guided closed biopsy.
. open surgical biopsy.
. antibiotic coverage for Staphylococcus aureus.
. broad-spectrum antibiotic coverage.
. a follow-up MRI scan in 8 weeks.

Correct Answer & Explanation

. CT-guided closed biopsy.

Explanation

DISCUSSION: The MRI scans show vertebral diskitis/osteomyelitis. The treatment of spinal infection in adults should be organism specific; therefore, initial management should consist of CT-guided closed biopsy prior to administration of antibiotic coverage. An open biopsy is indicated for a failed closed biopsy or failure of nonsurgical management. Although Staphylococcus aureus is the most common bacteria, a history of intravenous drug abuse raises suspicion for other organisms, including Pseudomonas.

Question 1678

Topic: Bone Tumors
A 65-year-old man has a painful right hip mass that has been growing for several years. A radiograph, CT scan, and photomicrograph are shown in Figures 56a through 56c. What is the most appropriate treatment?
. Chemotherapy alone
. Surgery alone
. Radiation therapy alone
. Chemotherapy and surgery
. Radiation therapy and surgery

Correct Answer & Explanation

. Surgery alone

Explanation

DISCUSSION: This is a conventional chondrosarcoma. The radiograph and the CT scan show a lesion arising from the inferior pubic ramus with a large soft-tissue mass. Abundant punctate, stippled, or “popcorn-like” calcification is present. The photomicrograph demonstrates hypercellular cartilage. Surgical resection is the only effective treatment. Whereas chemotherapy might play a role in the treatment of a dedifferentiated chondrosarcoma, it has no role in the treatment of a conventional chondrosarcoma. Chondrosarcomas are relatively radioresistant.

Question 1679

Topic: 10. Pathology and Oncology
What type of metastatic tumor most often has a lytic radiographic appearance?
. Breast
. Prostate
. Lung
. Osteosarcoma
. Bladder

Correct Answer & Explanation

. Lung

Explanation

DISCUSSION: Lung carcinoma most often has a lytic radiographic appearance. Bladder and prostate carcinoma are usually blastic. Breast carcinoma can be both blastic and lytic. Thyroid carcinoma may be difficult to visualize radiographically and may be seen only on MRI scans. Metastatic osteosarcomas typically produce bone. REFERENCES: Frassica FJ, Frassica DA, McCarthy EF, Riley LH III: Metastatic bone disease: Evaluation, clinicopathologic features, biopsy, fracture risk, nonsurgical treatment, and supportive management. Instr Course Lect 2000;49:453-459. Mulvey RB: Peripheral bone metastasis. Am J Roentgenol 1964;91:155.

Question 1680

Topic: 10. Pathology and Oncology
What is the most common malignancy involving the hand?
. Epithelioid sarcoma
. Synovial sarcoma
. Metastatic lung carcinoma
. Chondrosarcoma
. Squamous cell carcinoma

Correct Answer & Explanation

. Squamous cell carcinoma

Explanation

DISCUSSION: Skin cancers far outnumber primary musculoskeletal malignancies of the hand and the most common of these is squamous cell carcinoma. Metastatic lung carcinoma, while classic for the carcinoma that metastasizes to the hand, does so at an extremely low rate. REFERENCES: Fink JA, Akelman E: Nonmelanotic malignant skin tumors of the hand. Hand Clin 1995;11:255-264. Fleegler EJ: Skin tumors, in Green DP, Hotchkiss RN, Pederson WC (eds): Green’s Operative Hand Surgery, ed 4. Philadelphia, PA, Churchill Livingstone, 1999, vol 2, pp 2184-2205.

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