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10. Pathology and Oncology MCQs

Practice Set 100 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 1981

Topic: 10. Pathology and Oncology

A patient undergoes excision of a 3- x 3-cm soft-tissue sarcoma. The final histology results show tumor at the surgical margin. The surgical procedure performed is classified as

. intralesional.
. marginal.
. wide.
. wide contaminated.
. radical.

Correct Answer & Explanation

. intralesional.

Explanation

Surgical margins are classified according to the plane of dissection in relation to the tumor. An intralesional procedure is where the plane of dissection passes through the tumor. A marginal resection involves a resection where the plane of dissection is through the reactive zone of the tumor. A wide resection is through completely normal tissue outside of the reactive zone. A radical resection removes all of the muscles and/or bone of the compartment that are involved by the tumor.

Question 1982

Topic: 10. Pathology and Oncology

Figure 8a shows the clinical photograph of an 83-year-old woman who has an enlarging left forearm mass. MRI scans are shown in Figures 8b and 8c. What is the next most appropriate step in management?

. Radiation therapy
. Needle biopsy
. Marginal resection
. Chemotherapy
. Amputation

Correct Answer & Explanation

. Needle biopsy

Explanation

Any large (greater than 5 cm), deep, heterogeneous mass in the extremities should be considered a sarcoma until proven otherwise. Sarcomas are rare, and without a high index of suspicion, the lesions may be misdiagnosed or there may be a delay in diagnosis. Needle biopsies can obtain sufficient tissue for diagnosis and are associated with less morbidity than open biopsy. Marginal resections or excisional biopsies should be reserved for a few select benign lesions and locations. Damron TA, Beauchamp CP, Rougraff BT, et al: Soft-tissue lumps and bumps. Instr Course Lect 2004;53:625-637.

Question 1983

Topic: 10. Pathology and Oncology

Which of the following tumors is most likely to present with a pathologic fracture in a child?

Basic Science Board Review 2005: High-Yield MCQs (Set 2) - Figure 38

. Unicameral bone cyst
. Fibrous cortical defect
. Osteosarcoma
. Ewing's sarcoma
. Giant cell tumor

Correct Answer & Explanation

. Unicameral bone cyst

Explanation

In nearly 50% of patients with a unicameral bone cyst, the lesion remains asymptomatic until a fracture occurs, usually as the result of relatively minor trauma. If the lesion expands, the bone is weakened and may cause pain. Fibrous cortical defects are usually an incidental finding and typically asymptomatic. Malignant bone tumors such as osteosarcoma and Ewing's sarcoma most commonly cause pain, and pathologic fracture occurs in less than 10% of patients. Giant cell tumors are uncommon in children and usually are painful. Wilkins RM: Unicameral bone cysts. J Am Acad Orthop Surg 2000;8:217-224. Dormans JP, Pill SG: Fractures through bone cysts: Unicameral bone cysts, aneurysmal bone cysts, fibrous cortical defects, and nonossifying fibromas. Instr Course Lect 2002;51:457-467.

Question 1984

Topic: 10. Pathology and Oncology

A 9-year-old boy has pain over the midfoot medially with activity. Based on the findings shown in Figures 26a and 26b, which of the following is considered the most effective short-term management?

. Crutches and no weight bearing
. Core decompression
. Shoe inserts
. Temporary cast immobilization
. Nonsteroidal anti-inflammatory drugs

Correct Answer & Explanation

. Temporary cast immobilization

Explanation

While Kohler's disease has a benign course, temporary cast immobilization has been shown to result in a shortened duration of symptoms. Core decompression or other surgery is not warranted because of the benign nature. Shoe inserts may be beneficial, but there are no studies to support their use. Borges JL, Guile JT, Bowen JR: Kohler's bone disease of the tarsal navicular. J Pediatr Orthop 1995;15:596-598.

Question 1985

Topic: 10. Pathology and Oncology

A 32-year-old woman has had pain and a visibly growing mass in the shoulder for 3 years but denies any history of trauma. Examination reveals a swollen, boggy shoulder mass. The AP radiograph and MRI scan are shown in Figures 20a and 20b. Figures 20c through 20e show a portion of the excised mass and the photomicrographs of the biopsy specimen. What is the most likely diagnosis?

. Synovial chondromatosis
. Pigmented villonodular synovitis
. Synovial cell sarcoma
. Tuberculosis
. Chondrosarcoma

Correct Answer & Explanation

. Synovial chondromatosis

Explanation

The radiographic findings are classic for synovial chondromatosis because of the small calcified opacities within the joint surrounding the synovium. The histologic findings show cartilaginous foci of metaplasia, which may be markedly cellular. However, unlike low-grade chondrosarcoma, it lacks cellular and nuclear pleomorphism. Murphy FP, Dahlin DC, Sullivan CR: Articular synovial chondromatosis. J Bone Joint Surg Am 1982;44:77-86.

Question 1986

Topic: 10. Pathology and Oncology

A 28-year-old man has a painful nodule on the plantar aspect of his foot in the midarch. Use of a soft orthosis has failed to provide relief. Examination reveals that the mass is approximately 2 1/2 cm in diameter, firm, and tender to palpation. An MRI scan confirms the presence of a plantar fibroma. Management should now consist of

Foot & Ankle Board Review 2000: High-Yield MCQs (Set 2) - Figure 7

. local resection of the fibroma.
. resection of the entire plantar fascia.
. local radiation therapy.
. resection and adjuvant chemotherapy.
. Syme amputation.

Correct Answer & Explanation

. resection of the entire plantar fascia.

Explanation

Plantar fibromas have an extremely high recurrence rate (approximately 60%) with local excision only. Resection of the entire plantar fascia is effective at irradicating the lesion. There is no role for chemotherapy or amputation with plantar fibromatosis. Radiation therapy may be helpful in combination with resection of the plantar fascia. Kirby EJ, Shereff MJ, Lewis MM: Soft-tissue tumors and tumor-like lesions of the foot: An analysis of 83 cases. J Bone Joint Surg Am 1989;71:621-626.

Question 1987

Topic: 10. Pathology and Oncology

A 23-year-old woman has had vague left knee pain for the past 6 months. A radiograph and CT scan are shown in Figures 50a and 50b. What is the most likely diagnosis?

. Myositis ossificans
. Osteochondroma
. Parosteal osteosarcoma
. Dedifferentiated chondrosarcoma
. Tumoral calcinosis

Correct Answer & Explanation

. Parosteal osteosarcoma

Explanation

The radiographic appearance of the lesion emanating from the posterior cortex of the left distal femur is consistent with a surface bone-producing lesion; therefore, the most likely diagnosis is a parosteal osteosarcoma. In an osteochondroma, the cortex and medullary cavity of the lesion are in continuity with that of the native bone. A dedifferentiated chondrosarcoma has histologic components of a high-grade sarcoma plus a benign or low-grade malignant cartilage tumor. Tumoral calcinosis is characterized by amorphous calcium in the soft tissues and does not emanate from the bone itself. While often confused with parosteal osteosarcoma, myositis ossificans is usually more mature at the periphery of the lesion rather than the center. In addition, myositis ossificans does not involve the underlying cortex but remains separate from the bone. Unni KK: Dahlin's Bone Tumors: General Aspects and Data on 11,087 Cases, ed 5. Philadelphia, PA, Lippincott-Raven, 1996, pp 185-196.

Question 1988

Topic: 10. Pathology and Oncology

What is the most common primary malignant tumor of bone in childhood?

Basic Science Board Review 2005: High-Yield MCQs (Set 2) - Figure 37

. Periosteal chondroma
. Ewing's sarcoma
. Osteosarcoma
. Chondrosarcoma
. Rhabdomyosarcoma

Correct Answer & Explanation

. Osteosarcoma

Explanation

Osteosarcoma is the most common primary malignant tumor of bone in childhood, followed by Ewing's sarcoma. Rhabdomyosarcoma is a soft-tissue sarcoma of childhood. Chondrosarcoma rarely occurs in childhood. Osteochondromas are benign tumors of the bone. Simon M, Springfield D, et al: Osteogenic Sarcoma: Surgery for Bone and Soft Tissue Tumors. Philadelphia, PA, Lippincott Raven, 1998, p 226.

Question 1989

Topic: 10. Pathology and Oncology

A 15-year-old boy reports leg pain after being tackled during football practice. Radiographs and a CT scan are shown in Figures 46a through 46c. The patient has a pathologic fracture through what underlying lesion?

. Giant cell tumor
. Fibrous dysplasia
. Aneurysmal bone cyst
. Nonossifying fibroma
. Chondroblastoma

Correct Answer & Explanation

. Nonossifying fibroma

Explanation

The images show a lobulated, eccentric, well-marginated lesion that is typical of a nonossifying fibroma. The lesion is slightly expansile, and the CT scan findings show that the lesion is very well marginated and the cortex is disrupted, which is a common finding. None of the characteristics of this lesion is aggressive in nature. Menendez LR (ed): Orthopaedic Knowledge Update: Musculoskeletal Tumors. Rosemont, IL, American Academy of Orthopaedic Surgeons, 2002, pp 69-75.

Question 1990

Topic: 10. Pathology and Oncology

An 18-year-old boy has had pain in the right knee for the past 6 months. Examination reveals some fullness behind the knee but no significant palpable soft-tissue mass. There is no effusion, and he has full knee range of motion. The remainder of the examination is unremarkable. A radiograph and MRI scans are shown in Figures 33a through 33c, and biopsy specimens are shown in Figures 33d and 33e. What is the most likely diagnosis?

. Parosteal osteosarcoma
. Classic osteogenic sarcoma
. Ewing's sarcoma
. Osteochondroma
. Chondrosarcoma

Correct Answer & Explanation

. Parosteal osteosarcoma

Explanation

The patient has parosteal osteosarcoma. The posterior aspect of the distal femur is the typical location for this variant of osteogenic sarcoma. The imaging studies indicate a surface lesion with no involvement of the adjacent intramedullary canal. The histologic appearance is that of a low-grade fibroblastic osteosarcoma, consisting of relatively mature bone and a bland fibroblastic stroma lacking cytologic atypia and mitotic activity. A cartilaginous component is also frequently seen. Classic osteosarcoma typically has a more aggressive radiologic and histologic appearance. Sessile osteochondromas, while common behind the knee, have a presence of hematopoietic marrow and fat. The cartilage found in the associated cartilaginous cap is oriented. Chondrosarcomas are more typical in an older age group and have a histologic pattern consisting of malignant chondroid. Wold LA, et al: Atlas of Orthopaedic Pathology. Philadelphia, PA, WB Saunders, 1990, pp 20-21.

Question 1991

Topic: 10. Pathology and Oncology

A previously asymptomatic 14-year-old girl sustained a twisting injury to her ankle. Radiographs are shown in Figures 2a and 2b. Management should consist of

. observation.
. MRI.
. bone scan.
. biopsy.
. curettage and bone grafting.

Correct Answer & Explanation

. observation.

Explanation

The radiographs show a well-defined, irregular, eccentric lesion in the distal tibia metaphysis with a thin sclerotic margin. The radiographs are diagnostic of nonossifying fibroma, a common entity in this age group and in this location. No further work-up is indicated. The patient was asymptomatic prior to the injury and the lesion is small and thus not worrisome for an impending pathologic fracture; therefore, no treatment is indicated beyond observation. The natural history of these lesions is to gradually ossify as the patient reaches skeletal maturity. Menendez LR (ed): Orthopaedic Knowledge Update: Musculoskeletal Tumors. Rosemont, IL, American Academy of Orthopaedic Surgeons, 2002, pp 69-75.

Question 1992

Topic: 10. Pathology and Oncology

A 13-year-old boy has had pain and swelling in his ankle for the past several months. Based on the radiograph, MRI scan, and biopsy specimen shown in Figures 77a through 77c, what is the best course of action?

. Observation
. Curettage and bone grafting
. Radiofrequency ablation
. Radiation therapy
. Wide resection

Correct Answer & Explanation

. Curettage and bone grafting

Explanation

Chondroblastomas are benign cartilage lesions frequently seen in adolescents or young adults. They are found in the epiphyseal or apophyseal regions of bones. The radiograph shows a radiolucent lesion with mineralization and a well-marginated rim of reactive bone. The lesion is composed of sheets of immature chondroblasts (polygonal cells with a clear, bluish cytoplasm and a small round central nucleus). In some regions, classic "chicken-wire" matrix calcifications and a "cobblestone" pattern of cell arrangement may be seen. Treatment consists of curettage and bone grafting. Campanacci M: Bone and Soft Tissue Tumors, ed 2. New York, NY, Springer-Verlag, 1999, pp 247-264.

Question 1993

Topic: 10. Pathology and Oncology

A 14-year-old girl reports a 3-week history of anterior thigh pain and a palpable mass after sustaining a soccer-related injury. Examination reveals a tender, firm mass in the midportion of the rectus femoris. MRI scans are shown in Figures 39a through 39c. What is the most appropriate management?

. Incision and drainage of the abscess
. Nonsteroidal anti-inflammatory drugs, physical therapy, and a repeat MRI scan in 6 to 8 weeks
. Open biopsy
. Hematoma evacuation and musculotendinous repair
. Primary wide resection followed by radiation therapy

Correct Answer & Explanation

. Nonsteroidal anti-inflammatory drugs, physical therapy, and a repeat MRI scan in 6 to 8 weeks

Explanation

The history, examination, and MRI scan findings are consistent with a midsubstance partial rupture of the rectus femoris muscle. This is an injury masquerading as a "pseudo tumor." The lack of an appreciable mass effect on the T1-weighted MRI scan, the defined fluid signal on the T2-weighted scans, and the lack of significant contrast enhancement after gadolinium are all most consistent with injury rather than a neoplasm. Most of these injuries respond to nonsurgical management; a few will benefit from late debridement and repair if symptoms fail to resolve in 3 to 6 months. The treatment of choice is nonsurgical management with a follow-up MRI scan to verify that the findings are resolving. Hughes C IV, Hasselman CT, Best TM, et al: Incomplete, intrasubstance strain injuries of the rectus femoris muscle. Am J Sports Med 1995;23:500-506.

Question 1994

Topic: 10. Pathology and Oncology

A 43-year-old soccer player who had knee pain following a twisting injury underwent an arthroscopic meniscectomy 6 months ago. He continues to report posterior knee pain. Examination reveals soft-tissue fullness and tenderness just above the popliteal fossa, trace knee effusion, full range of knee motion, no instability, and negative meniscal signs. Radiographs show some mild medial joint space narrowing but no other bony changes. What is the next most appropriate step in management?

. Corticosteroid injection
. MRI
. Bone scan
. Unloader brace
. Nonsteroidal anti-inflammatory drugs

Correct Answer & Explanation

. MRI

Explanation

The phenomenon of tumors misdiagnosed as athletic injuries has been termed "sports tumors." Lewis and Reilly presented a series of 36 patients who initially were thought to have a sports-related injury but ultimately were diagnosed with a primary bone tumor, soft-tissue tumor, or tumor-like condition. Muscolo and associates presented a series of 25 tumors that had been previously treated with an intra-articular procedure as a result of a misdiagnosis of an athletic injury. Initial diagnoses included 21 meniscal lesions, one traumatic synovial cyst, one patellofemoral subluxation, one anterior cruciate ligament tear, and one case of nonspecific synovitis. The final diagnoses were a malignant tumor in 14 patients and a benign tumor in 11 patients. The authors noted that oncologic surgical treatment was affected in 15 of the 25 patients. The most frequent causes of erroneous diagnosis were initial poor quality radiographs and an unquestioned original diagnosis despite persistent symptoms. Persistent symptoms warrant further diagnostic studies, not additional treatment such as physical therapy, corticosteroid injection, or an unloader brace. Although a bone scan may be helpful in this case and confirm arthrosis of the medial compartment, the suspicion of a soft-tissue mass makes MRI the imaging modality of choice. Muscolo DL, Ayerza MA, Makino A, et al: Tumors about the knee misdiagnosed as athletic injuries. J Bone Joint Surg Am 2003;85:1209-1214.

Question 1995

Topic: 10. Pathology and Oncology
Figures 48a through 48c show the lateral radiograph and MRI scans of a 60-year-old man who has had pain in his thigh for 1 month. The next most appropriate step in management should consist of
. insertion of a locked intramedullary nail.
. a bone scan, a radiograph of the chest, and CT of the chest, abdomen, and pelvis.
. compression plating.
. upper and lower gastrointestinal (GI) studies.
. radiation therapy.

Correct Answer & Explanation

. a bone scan, a radiograph of the chest, and CT of the chest, abdomen, and pelvis.

Explanation

The patient has a presumed metastatic bone tumor. The approach to evaluating a patient with a bone tumor of unknown primary origin is to obtain laboratory studies that include a CBC, an erythrocyte sedimentation rate, a serum protein electrophoresis, a calcium level, a urinalysis, and a prostate-specific antigen. In addition, a bone scan, a radiograph of the chest, and CT scans of the chest and abdomen should be obtained. These evaluations can identify the primary site in 85% of patients. GI studies rarely are of diagnostic value. Prophylactic stabilization is contraindicated until a diagnosis is confirmed by histology.

Question 1996

Topic: 10. Pathology and Oncology

A 6-year-old boy presents with a mass and a lucent lesion involving the tibial shaft as seen in Figure 17a. The mass is mildly tender to palpation. The bone scan is focally hot in the tibia. Biopsy specimens are shown in Figures 17b and 17c. What is the most likely diagnosis?

. Giant cell tumor
. Nonossifying fibroma
. Fibrous dysplasia
. Eosinophilic granuloma
. Osteofibrous dysplasia

Correct Answer & Explanation

. Osteofibrous dysplasia

Explanation

Osteofibrous dysplasia frequently presents at a very young age, usually less than 10 years. In most patients, it involves the anterior cortex of the tibial shaft and minor anterior bowing of the tibia is frequently seen. The lesion is unpredictable in nature, but local recurrence is very high in patients who undergo surgery before 15 years of age. Campanacci M, Laus M: Osteofibrous dysplasia of the tibia and fibula. J Bone Joint Surg Am 1981;63:367-375.

Question 1997

Topic: 10. Pathology and Oncology

The spread of malignant cells to the vertebrae is often through

. epidural extension.
. Batson's vertebral plexus.
. the lymphatic system.
. direct tumor extension.
. arterial circulation including the artery of Adamkiewicz.

Correct Answer & Explanation

. Batson's vertebral plexus.

Explanation

In 1940, Batson described a valveless plexus of veins that extend from the dural venous sinuses of the skull to the sacrum. This system permits retrograde blood flow and enables tumor cells to enter vertebral bodies at multiple levels. Increased intra-abdominal pressure will enhance this retrograde blood flow.

Question 1998

Topic: 10. Pathology and Oncology

A 78-year-old man being seen for routine follow-up studies reports mild to moderate pain in his left arm. The patient has a history of lung cancer and severe heart disease. A radiograph and a bone scan are shown in Figures 36a and 36b. Treatment should consist of

. intramedullary fixation.
. arterial embolization.
. curettage and cementation.
. radiation therapy.
. segmental resection and reconstruction using a diaphyseal metal spacer.

Correct Answer & Explanation

. radiation therapy.

Explanation

The patient has lung cancer metastatic to the left humerus that is mildly to moderately symptomatic. Radiographically, the lesion is small and is not associated with significant cortical destruction. Metastatic lesions in the upper extremity have a lower incidence of pathologic fracture than lesions in the lower extremity.

Question 1999

Topic: 10. Pathology and Oncology

A 16-year-old boy has had thigh pain for the past several months. He denies any history of trauma. Examination reveals a large, deeply fixed, soft-tissue mass in the thigh. Laboratory results show an elevated erythrocyte sedimentation rate (ESR) and leukocytosis. A plain radiograph and MRI scan are shown in Figures 1a and 1b. Biopsy specimens are shown in Figures 1c and 1d. What is the most likely diagnosis?

. Ewing's sarcoma
. Osteomyelitis
. Osteosarcoma
. Chondrosarcoma
. Giant cell tumor of bone

Correct Answer & Explanation

. Ewing's sarcoma

Explanation

Ewing's sarcoma typically can occur in the diaphysis of the long bones (50% to 55%). It is often accompanied by a large soft-tissue mass. Abnormal findings are common, including a low-grade fever, an elevated ESR, and leukocytosis. The histology is consistent with a small round blue cell tumor. The unique pathology and other findings exclude osteosarcoma. Giant cell tumor and chondrosarcoma have a different histologic appearance and typically are more metaphyseal in location. Chondrosarcoma typically is found in older age groups, has a different histologic pattern, and rarely occurs in the midshaft of the femur.

Question 2000

Topic: 10. Pathology and Oncology

A 21-year-old collegiate female cross-country athlete reports right hip pain that begins about 12 miles into a run, followed by pain resolution when she discontinues running. However, each time she tries to resume a running program, she experiences recurrence of pain deep in the anterior groin. A plain radiograph and MRI scan are shown in Figures 8a and 8b. Management should consist of

. cessation of running and implementation of cross training until healing is complete.
. a bone scan, skeletal survey, and chest radiographs to assess for other sites of involvement.
. a radioisotope injection and scintinigraphic-guided percutaneous biopsy.
. percutaneous fixation with multiple cannulated screws.
. excision, bone grafting, and internal fixation.

Correct Answer & Explanation

. cessation of running and implementation of cross training until healing is complete.

Explanation

The history is consistent with a stress fracture. Findings on the plain radiograph are marginal, but the MRI scan shows evidence of stress reaction in the medial neck of the femur (compression side). A lesion on the compression side is not normally at risk for displacement and usually can be managed nonsurgically. A bone scan would further identify the lesion but is not necessary. A skeletal survey and chest radiograph are used in staging a tumor. Radioisotope injection and guided biopsy are sometimes used for osteoid osteomas. Boden BP, Osbahr DC: High-risk stress fractures: Evaluation and treatment. J Am Acad Orthop Surg 2000;8:344-353.

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