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10. Pathology and Oncology MCQs

Practice Set 109 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 2161

Topic: 10. Pathology and Oncology

A 25-year-old man has a mass on the medial aspect of the left knee. He reports that the mass has been present for several years, but a recent increase in physical activity has resulted in periodic tenderness. Radiographs are shown in Figures 13a and 13b. What is the most likely diagnosis?

. Osteochondroma
. Enchondroma
. Myositis ossificans
. Parosteal osteosarcoma
. Prior bony trauma

Correct Answer & Explanation

. Osteochondroma

Explanation

The radiographs reveal a sessile lesion projecting from the medial aspect of the distal femur. The lesion shares the cortex with the bone and the base communicates with the medullary space of the femur. This is the classic appearance of an osteochondroma, the most common benign tumor of bone. Menendez LR (ed): Orthopaedic Knowledge Update: Musculoskeletal Tumors. Rosemont, IL, American Academy of Orthopaedic Surgeons, 2002, pp 103-111.

Question 2162

Topic: 10. Pathology and Oncology

In 1980, a 32-year-old woman was found to have right breast mass, and a biopsy revealed adenocarcinoma. She underwent a mastectomy at that time, with no other treatment. Five years later, she noticed a lump in the left breast and underwent a left mastectomy. Seven lymph nodes were positive. In 2006, she now reports hip and thigh pain for the past 3 months. Figures 69a and 69b show AP and lateral radiographs of the femur. A bone scan shows a solitary lesion. Following radiographic staging, what is the next most appropriate step in management?

. Protected weight bearing and radiation therapy
. Intramedullary rodding of the femur with curettage and cementation
. Intramedullary rodding of the femur without curettage and cementation
. Biopsy of the lesion
. Resection and reconstruction

Correct Answer & Explanation

. Biopsy of the lesion

Explanation

Solitary bone lesions require biopsy, for there is the possibility that the lesion may represent a primary bone sarcoma, which will necessitate a different treatment plan. This is especially true in patients with remote histories of cancer. The most likely cause of a lytic bone lesion in a patient older than age 40 years is a metastatic lesion. Rougraff BT, Kneisl JS, Simon MA: Skeletal metastases of unknown origin: A prospective study of a diagnostic strategy. J Bone Joint Surg Am 1993;75:1276-1281.

Question 2163

Topic: 10. Pathology and Oncology

A 14-year-old boy has a midshaft fibular lesion. Biopsy results are consistent with Ewing's sarcoma. Following induction chemotherapy, local control typically consists of

Basic Science Board Review 2002: High-Yield MCQs (Set 2) - Figure 37

. radiation therapy only.
. curettage and bone grafting.
. wide excision.
. below-knee amputation.
. observation.

Correct Answer & Explanation

. wide excision.

Explanation

Current treatment regimens for Ewing's sarcoma typically involve induction chemotherapy followed by local control and further chemotherapy. Local control consists of surgery alone, radiation therapy alone, or a combination of the two. In bones that are easily resectable (or expendable) with wide margins, surgery alone is usually recommended. For areas that are unresectable (ie, large, bulky pelvic tumors), radiation therapy alone is sometimes the preferred method of local control. If surgery is chosen and margins are close, radiation therapy can be used as an adjuvant. Amputation rarely is required for an isolated fibular lesion. Observation without adequate local therapy results in local recurrence. Nesbit ME Jr, Gehan EA, Burgert EO Jr, et al: Multimodal therapy for the management of primary, nonmetastatic Ewing's sarcoma of bone: A long-term follow-up of the First Intergroup study. J Clin Oncol 1990;8:1664-1674.

Question 2164

Topic: 10. Pathology and Oncology

A 43-year-old man has had right groin pain for the past 3 months. A radiograph, CT scan, and biopsy specimen are shown in Figures 18a through 18c. What is the most likely diagnosis?

. Chordoma
. Enchondroma
. Dedifferentiated chondrosarcoma
. Chondrosarcoma
. Metastatic renal cell carcinoma

Correct Answer & Explanation

. Chondrosarcoma

Explanation

The radiographic appearance of the lesion is lytic with calcifications in the supra-acetabular region. The CT scan shows bone destruction and periosteal reaction, which rules out an enchondroma. The histologic appearance is that of cellular cartilage, with a high cytoplasmic:nuclear ratio and basophilic appearance to the cytoplasm; these findings rule out chordoma and metastatic renal cell carcinoma. In addition, chordomas are most frequently found in the sacrum and base of the skull. Because there is no high-grade spindle cell component to suggest dedifferentiation, the most likely diagnosis is chondrosarcoma. Pring M, Weber KL, Unni K, Sim FH: Chondrosarcoma of the pelvis: A review of sixty-four cases. J Bone Joint Surg Am 2001;83:1630-1642.

Question 2165

Topic: 10. Pathology and Oncology

A 14-year-old boy has an anteromedial distal thigh mass. A radiograph and MRI scan are shown in Figures 39a and 39b. An open biopsy of the mass should include

. bone obtained through a knee arthrotomy with creation of a portal that will be used for retrograde femoral nailing.
. bone obtained by going through the mass.
. bone obtained through a posterior approach, dissecting out and protecting the sciatic nerve and popliteal artery.
. soft tissue obtained through a longitudinal incision centered over the mass.
. soft tissue obtained through a transverse incision on the medial thigh.

Correct Answer & Explanation

. bone obtained by going through the mass.

Explanation

Biopsy of the soft-tissue component is often diagnostic. Alternatively, in centers with pathologists familiar with bone tumors, needle biopsy is usually successful. The principles of biopsy of bone tumors include avoiding contamination of uninvolved structures and compartments, taking the most direct path to the tumors, making an excisable biopsy tract, and obtaining diagnostic tissue. Transverse biopsy incisions should be avoided because they hinder the definitive surgical procedure. Peabody TD, Simon MA: Making the diagnosis: Keys to a successful biopsy in children with bone and soft-tissue tumors. Orthop Clin North Am 1996;27:453-459. Mankin HJ, Mankin CJ, Simon MA: The hazards of the biopsy, revisited. Members of the Musculoskeletal Tumor Society. J Bone Joint Surg Am 1996;78:656-663.

Question 2166

Topic: 10. Pathology and Oncology

Figure 46 shows the MRI scan of a patient who has a mass in the calf that has been fluctuating in size. Radiographs are negative. Which of the following procedures will most quickly aid in confirming the diagnosis?

Basic Science Board Review 2002: High-Yield MCQs (Set 4) - Figure 23

. Open biopsy
. Needle aspiration
. Arthroscopy
. CT
. Arthrography

Correct Answer & Explanation

. Needle aspiration

Explanation

The bright signal on the T2-weighted MRI scan suggests fluid. The multiloculated appearance in proximity to the proximal tibiofibular joint suggests that the most likely diagnosis is a ganglion. They typically increase and decrease in size and can be diagnosed by the classic gelatinous fluid obtained through needle aspiration. Bianchi S, Abdelwahab IF, Kenan S, Zwass A, Ricci G, Palomba G: Intramuscular ganglia arising from the superior tibiofibular joint: CT and MR evaluation. Skeletal Radiol 1995;24:253-256.

Question 2167

Topic: 10. Pathology and Oncology
A 20-year-old man has a large soft-tissue mass behind his knee. MRI scans are shown in Figures 10a through 10c. Figure 10d shows a clinical photograph of his chest. The patient's condition is most likely a result of a defect in what gene?
. NF1
. EWS
. EXT1
. P53
. Rb

Correct Answer & Explanation

. NF1

Explanation

The patient has a plexiform neurofibroma and multiple café-au-lait spots, all characteristic of von Recklinghausen's neurofibromatosis. This disease has been linked to a defect of the gene NF1 on chromosome 17. EWS is one of the genes associated with the 11;22 translocation found in Ewing's sarcoma and several other sarcomas. EXT1 is the most common gene affecting patients with multiple hereditary exostosis. P53 and Rb are tumor suppressor genes whose inactivation has been associated with tumors in conditions such as Li-Fraumeni and retinoblastoma, respectively. Theos A, Korf BR, American College of Physicians, et al: Pathophysiology of neurofibromatosis Type 1. Ann Intern Med 2006;144:842-849.

Question 2168

Topic: Bone Tumors

A 31-year-old woman has a history of a painful ankle that has failed to respond to conservative management. She has associated night pain that is relieved with nonsteroidal anti-inflammatory drugs. MRI and technetium Tc 99m scans are consistent with an osteoid osteoma. Management should now consist of

. curettage or en bloc resection.
. allograft limb salvage.
. injection with 5% phenol.
. radiation therapy.
. hormonal therapy.

Correct Answer & Explanation

. curettage or en bloc resection.

Explanation

Surgical curettage or en bloc resection is the treatment of choice for osteoid osteoma. Night pain and relief of symptoms with nonsteroidal anti-inflammatory drugs are classic findings for osteoid osteoma. Donley BG, Philbin T, Rosenberg GA, Schils JP, Recht M: Percutaneous CT guided resection of osteoid osteoma of the tibial plafond. Foot Ankle Int 2000;21:596-598. Kenzora JE, Abrams RC: Problems encountered in the diagnosis and treatment of osteoid osteoma of the talus. Foot Ankle 1981;2:172-178.

Question 2169

Topic: 10. Pathology and Oncology

A 16-year-old girl injured her hip in a fall. Radiographs are shown in Figures 14a and 14b. She denies any history of pain prior to the fall and is currently asymptomatic. A bone scan, MRI scan, and biopsy specimens are shown in Figures 14c through 14f. What is the most likely diagnosis?

. Osteosarcoma
. Fibrous dysplasia
. Osteoblastoma
. Ossifying fibroma
. Osteomyelitis

Correct Answer & Explanation

. Fibrous dysplasia

Explanation

Although the classic radiographic appearance of fibrous dysplasia is one of a central metaphyseal lesion with ground glass matrix, it is not unusual to see either a more radiodense-appearing lesion or a more peripheral location. The histologic finding of spicules of woven bone without osteoblastic rimming in a bland fibrous background is diagnostic of fibrous dysplasia. The imaging studies could be consistent with low-grade osteosarcoma, osteoblastoma, or osteomyelitis, but all have a very different histologic picture. Observation is indicated in the absence of symptoms, impending fracture, or deformity. Fibrous dysplasia most commonly occurs in the proximal femur. Huvos AG: Bone Tumors: Diagnosis, Treatment, and Prognosis. Philadelphia, PA, WB Saunders, 1991, pp 30-43.

Question 2170

Topic: Bone Tumors

An otherwise healthy 75-year-old man has a painful mass in the popliteal fossa of his right knee. A lateral radiograph of the knee, a CT scan of the distal femur, and a histopathologic specimen are shown in Figures 13a through 13c. Management should consist of

. observation.
. radiation therapy.
. radiation therapy and chemotherapy.
. surgical resection.
. surgical resection and chemotherapy.

Correct Answer & Explanation

. surgical resection.

Explanation

The patient has a parosteal osteosarcoma of the distal femur. The findings of mild knee pain, radiographic evidence of a radiodense mass involving the parosseous space or surface of the distal femur, and histologic findings of a spindle cell lesion forming immature osteoid with little to no necrosis most likely suggest a parosteal osteosarcoma. The treatment of choice is surgical resection. Okada K, Frassica FJ, Sim FH, Beabout JW, Bond JR, Unni KK: Parosteal osteosarcoma: A clinicopathological study. J Bone Joint Surg Am 1994;76:366-378.

Question 2171

Topic: 10. Pathology and Oncology

A 10-year-old boy has had a prominent scapula for the past year. He reports crepitus and aching over the area, but only when he is active. A radiograph and CT scans are shown in Figures 37a through 37c. What is the most likely diagnosis?

. Enchondroma
. Osteochondroma
. Chondroblastoma
. Ewing's sarcoma
. Chondrosarcoma

Correct Answer & Explanation

. Osteochondroma

Explanation

The findings are typical for an osteochondroma. It is found as an outgrowth of bone and cartilage from those bones that arise from enchondral ossification. It may be flat, verrucous, or with a long stalk and cauliflower-like cap. Osteochondromas can become symptomatic secondary to irritation of the adjacent musculature. They cease to proliferate when epiphyseal growth ceases.

Question 2172

Topic: 10. Pathology and Oncology

A 21-year-old man has had posterior neck discomfort for the past 6 months. Radiographs, an MRI scan, and a photomicrograph of the biopsy specimen are shown in Figures 17a through 17d. What is the most likely diagnosis?

. Fibrous dysplasia
. Osteochondroma
. Osteoblastoma
. Giant cell tumor
. Hemangioma

Correct Answer & Explanation

. Osteoblastoma

Explanation

Forty percent of osteoblastomas occur in the spine, and they can become large and locally aggressive lesions. They generally occur in the posterior elements but can occur in the ribs and transverse processes. Microscopic analysis of the lesion will reveal hyperchromatic osteoblasts separated by incompletely mineralized bars of bone. Recommended treatment is en bloc excision. Fibrous dysplasia, giant cell tumor, and hemangioma can have similar radiographic appearances; therefore, biopsy may be required to differentiate them from more aggressive lesions. Osteochondromas are characterized by an osteocartilaginous growth arising from the cortex. Bridwell KH, Ogilvie JW: Primary tumors of the spine, in Bridwell KH, DeWald RL (eds): The Textbook of Spinal Surgery. Philadelphia, PA, JB Lippincott, 1991, vol 2, pp 1143-1174.

Question 2173

Topic: 10. Pathology and Oncology

A 37-year-old man has had isolated chronic knee swelling for the past 6 months. He denies any history of specific trauma. Examination reveals a large effusion with a stable knee, but the remainder of the examination is normal. Plain radiographs are unremarkable. An MRI scan reveals a large effusion without meniscal injury. An arthroscopic image of the suprapatellar pouch is shown in Figure 23. What is the most likely diagnosis?

Sports Medicine 2004 Practice Questions: Set 3 (Solved) - Figure 2

. Septic arthritis
. Chondromalacia of the medial femoral condyle
. Synovial cell sarcoma
. Rheumatoid arthritis
. Pigmented villonodular synovitis (PVNS)

Correct Answer & Explanation

. Pigmented villonodular synovitis (PVNS)

Explanation

The history and physical examination are consistent with a monoarticular joint condition but not typical of joint sepsis. The arthroscopic appearance of brownish proliferative synovium is typical of PVNS. PVNS is a monoarticular synovial disease of unknown etiology and is treated with total synovectomy. The proliferative synovitis is not consistent with chondromalacia. Synovial cell sarcoma is an extracapsular disease. Rheumatoid arthritis typically is polyarticular, and the synovial appearance is not associated with hemosiderin deposition. Flandry FC, Hughston JC, Jacobson KE, Barrack RL, McCann SB, Kurtz DM: Surgical treatment of diffuse pigmented villonodular synovitis of the knee. Clin Orthop 1994;300:183-192.

Question 2174

Topic: 10. Pathology and Oncology
A 17-year-old girl who initially presented as a child with multiple skeletal lesions, café-au-lait spots, and precocious puberty now has bone pain. A recent bone scan reveals multiple areas of increased scintigraphic uptake, including bilateral proximal femurs. A radiograph is shown in Figure 19. Besides activity modification, what is the next best line of treatment for decreasing her pain?
. Bisphosphonates
. Calcitonin
. Parathyroid hormone
. Vitamin D and calcium
. Methotrexate

Correct Answer & Explanation

. Bisphosphonates

Explanation

McCune-Albright syndrome is the combination of polyostotic fibrous dysplasia, café-au-lait lesions, and endocrine dysfunction. The most common endocrine presentation is precocious development of secondary sexual characteristics. Compared with bone lesions in patients without polyostotic disease, the skeletal lesions in patients with the syndrome tend to be larger, more persistent, and associated with more complications. Bisphosphonate therapy has been shown in several studies to decrease the pain associated with the skeletal lesions of fibrous dysplasia. DiCaprio MR, Enneking WF: Fibrous dysplasia: Pathophysiology, evaluation and treatment. J Bone Joint Surg Am 2005;87:1848-1864.

Question 2175

Topic: 10. Pathology and Oncology

The therapeutic effect of etanercept in the treatment of rheumatoid arthritis is primarily mediated through

. antagonism of tumor necrosis factor-alpha (TNF-a).
. antagonism of matrix metalloproteinases (MMPs).
. inhibition of COX2.
. stimulation of interleukin-1 (IL-1).
. stimulation of tissue inhibitors of metalloproteinases (TIMPs).

Correct Answer & Explanation

. antagonism of tumor necrosis factor-alpha (TNF-a).

Explanation

Etanercept is a fusion protein that combines the ligand-binding domain of the TNF-a receptor to the Fc portion of human immunoglobulin G (IgG). Protein serves as a competitive inhibitor of TNF-a signaling. COX2 is the target of NSAIDs, including newer formulations that are more COX2-specific. The remaining responses are not direct targets of etanercept. Weinblatt ME, Kremer JM, Bankhurst AD, et al: A trial of etanercept, a recombinant tumor necrosis factor receptor: Fc fusion protein, in patients with rheumatoid arthritis receiving methotrexate. N Engl J Med 1999;340:253-259.

Question 2176

Topic: 10. Pathology and Oncology

Figures 10a and 10b show the clinical photograph and MRI scan of a plantar foot lesion. If excisional biopsy is performed, what is the most likely complication?

. Metastatic spread
. Recurrence of the lesion
. High likelihood of wound breakdown
. Injury to the medial plantar nerve
. Loss of the local windlass effect of the plantar fascia

Correct Answer & Explanation

. Recurrence of the lesion

Explanation

The MRI scan shows plantar fibromatosis. The treatment is usually nonsurgical. If surgery is indicated, wide local excision with excision of the entire plantar fascia is usually indicated. The main problem with simple excision of the lesion is the high chance of recurrence. The other listed complications are those that are a result of the wide local excision. Aluisio FV, Mair SD, Hall RL: Plantar fibromatosis: Treatment of primary and recurrent lesions and factors associated with recurrence. Foot Ankle Int 1996;17:672-678.

Question 2177

Topic: 10. Pathology and Oncology

A 37-year-old woman has had intermittent paresthesias and numbness in the plantar foot for the past 6 months. She reports that the symptoms are worse with activity, and the paresthesias are beginning to awaken her at night. MRI scans are shown in Figures 6a and 6b. What is the most likely diagnosis?

. Lipoma
. Giant cell tumor of the tendon sheath
. Synovial sarcoma
. Metastatic adenocarcinoma
. Ganglion cyst

Correct Answer & Explanation

. Ganglion cyst

Explanation

The symptoms are consistent with tarsal tunnel syndrome. Ganglion cysts are a well-known cause of tarsal tunnel syndrome. The MRI scans show a high intensity, well-circumscribed mass in the tarsal tunnel that is consistent with a fluid-filled cyst. Patients usually respond well to excision of the ganglion and resolution of the tarsal tunnel symptoms. The surrounding fat is a different signal intensity on the MRI scans, which rules out a lipoma. Synovial cell sarcoma has a heterogeneous appearance on an MRI scan. Metastatic tumors are most commonly found in the osseous structures of the foot, not the soft tissues. Rozbruch SR, Chang V, Bohne WH, et al: Ganglion cysts of the lower extremity: An analysis of 54 cases and review of the literature. Orthopedics 1998;21:141-148. Llauger J, Palmer J, Monill JM, et al: MR imaging of benign soft-tissue masses of the foot and ankle. Radiographics 1998;18:1481-1498.

Question 2178

Topic: 10. Pathology and Oncology

A 15-year-old boy has had pain in the right knee for the past 3 months. He denies any history of trauma. Examination reveals a firm mass in the distal thigh; the remainder of the examination is unremarkable. A radiograph is shown in Figure 24. What further work-up should be completed prior to biopsy?

Basic Science Board Review 2005: High-Yield MCQs (Set 2) - Figure 36

. None
. MRI of the distal femur
. MRI of the entire femur
. MRI of the entire femur and a bone scan
. MRI of the entire femur, CT of the chest, and a bone scan

Correct Answer & Explanation

. MRI of the entire femur, CT of the chest, and a bone scan

Explanation

The radiograph shows an aggressive destructive lesion. In this age group, and based on the anatomic location, a primary malignant tumor (osteosarcoma) is likely. Additional staging studies to identify metastatic disease are imperative prior to any biopsy. MRI of the femur helps to reveal skip metastasis and provides information regarding the anatomic location of the lesion. CT of the chest and a bone scan evaluate for distant metastatic spread. A bone scan is also useful in evaluating the extent of local bone activity about the lesion. Simon MA, Finn HA: Diagnostic strategy for bone and soft tissue tumors. J Bone Joint Surg Am 1993;75:622-631.

Question 2179

Topic: 10. Pathology and Oncology

Figures 6a through 6d show the radiographs and biopsy specimens of an 8-year-old girl with leg pain. Management of the lesion should consist of

. wide resection and salvage of the physis.
. resection and hemicondylar osteoarticular allograft.
. cryosurgery.
. radiation therapy.
. curettage and bone grafting.

Correct Answer & Explanation

. curettage and bone grafting.

Explanation

The biopsy specimens show a chondromyxoid fibroma with varying amounts of cartilage, benign fibrous tissue, giant cells, and loose myxoid areas. Chondromyxoid fibroma is a benign active bone lesion that is best treated with aggressive curettage and bone grafting. Although recurrences are common, more aggressive treatment is not warranted initially. Wilson AJ, Kyriakos M, Ackerman LV: Chondromyxoid fibroma: Radiographic appearance in 38 cases and in a review of the literature. Radiology 1991;179:513-518.

Question 2180

Topic: 10. Pathology and Oncology

A 40-year-old man has a painful mass on his anterior ankle joint with limited range of motion. A radiograph, MRI scan, a gross specimen, and a hematoxylin/eosin biopsy specimen are shown in Figures 5a through 5d. What is the most likely diagnosis?

. Infection
. Tuberculosis
. Pigmented villonodular synovitis
. Synovial chondromatosis
. Metastatic adenocarcinoma

Correct Answer & Explanation

. Synovial chondromatosis

Explanation

Synovial chondromatosis results from chondroid metaplasia within the synovium. Male to female ratio is 2:1, with a peak incidence in early adult life. Radiographs can show speckled cal

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