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10. Pathology and Oncology MCQs

Practice Set 104 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 2061

Topic: 10. Pathology and Oncology

Figures 13a and 13b show the MRI scans of a 70-year-old patient who has a posterior calf mass. Examination reveals that the mass extends to the midcalf level. A biopsy specimen reveals a high-grade soft-tissue sarcoma. Metastatic work-up shows no lesions. Management should consist of

. wide resection and radiation therapy.
. wide resection and chemotherapy.
. below-knee amputation.
. observation.
. radiation therapy.

Correct Answer & Explanation

. below-knee amputation.

Explanation

Soft-tissue sarcomas generally are treated with radiation therapy and wide surgical resection. In this patient, involvement of most of the posterior calf compartment and circumferential involvement of the posterior tibial and peroneal neurovascular bundle makes limb salvage impractical. Any attempt at wide surgical resection would leave a poorly functioning limb with questionable surgical margins. A high below-knee amputation would be the best option. Radiation therapy alone is contraindicated. Lindberg RD, Martin RG, Romsdahl MM, et al: Conservative surgery and post-operative radiotherapy in 300 adults with soft tissue sarcoma. Cancer 1981;47:2391-2397. Sim FT, Frassica FS, Frassica DA: Soft tissue tumors: Diagnosis, evaluation, and management. J Am Acad Orthop Surg 1994;2:202-211.

Question 2062

Topic: 10. Pathology and Oncology

A 30-year-old woman has pain in her right hand. The radiograph, CT scan, and biopsy specimen are seen in Figures 38a through 38c. What is the most likely diagnosis?

. Enchondroma
. Giant cell tumor
. Metastatic carcinoma
. Degenerative cyst
. Eosinophilic granuloma

Correct Answer & Explanation

. Enchondroma

Explanation

An enchondroma is the most common primary tumor of the long bones of the hand. The lesion is usually asymptomatic and often is detected when there is a pathologic fracture. Shimizu K, Kotoura Y, Nishijima N, Nakamura T: Enchondroma of the distal phalanx of the hand. J Bone Joint Surg Am 1997;79:898-900.

Question 2063

Topic: 10. Pathology and Oncology

Figures 26a and 26b show the radiograph and MRI scan of a 22-year-old man with knee pain. What is the most likely diagnosis?

. Osteochondroma
. Osteoblastoma
. Osteosarcoma
. Chondrosarcoma
. Malignant fibrous histiocytoma of bone

Correct Answer & Explanation

. Osteochondroma

Explanation

The lesion is an osteochondroma. This is demonstrated by a pedunculated bone-forming lesion where the medullary space of the lesion communicates with the medullary space of the host bone. The cortex of the exostosis is in continuity with the cortex of the underlying bone. The MRI scan reveals that there is no significant cartilage cap, alleviating concern for malignant conversion to a chondrosarcoma. Osteoblastoma and osteosarcoma typically have mixed areas of bone formation and bone destruction. Malignant fibrous histiocytoma of bone is usually purely lytic. Vaccaro AR (ed): Orthopaedic Knowledge Update 8. Rosemont, IL, American Academy of Orthopaedic Surgeons, 2005, pp 197-215.

Question 2064

Topic: 10. Pathology and Oncology

A 15-year-old girl reports a 6-month history of activity-related knee pain and swelling. A radiograph, MRI scan, and biopsy specimen are shown in Figures 21a through 21c. What is the most likely diagnosis?

. Enchondroma
. Giant cell tumor
. Chondroblastoma
. Osteoblastoma
. Chondromyxoid fibroma

Correct Answer & Explanation

. Chondroblastoma

Explanation

The epiphyseal location on the radiograph and MRI scan and the histologic findings of polyhedral cells separated by a chondroid matrix with pericellular, lattice-like "chicken wire" calcification all suggest chondroblastoma. Although giant cell tumors of bone typically occupy an epiphyseal location, they are rare in children and when present are often metaphyseal in skeletally immature patients. Enchondromas and osteoblastomas are generally metaphyseal and, along with giant cell tumors, have very different histology than seen here. Chondromyxoid fibromas are typically metaphyseal in location. Huvos AG: Bone Tumors: Diagnosis, Treatment, and Prognosis. Philadelphia, PA, WB Saunders, 1991, pp 295-313.

Question 2065

Topic: 10. Pathology and Oncology

An adult patient has an 8- x 4- x 10-cm soft-tissue mass located within the adductor compartment of the thigh. Staging studies should consist of

Basic Science 2002 Practice Questions: Set 1 (Solved) - Figure 47

. MRI and a radiograph of the thigh and CT of the chest.
. MRI of the thigh, a chest radiograph, and a CT of the pelvis.
. MRI of the thigh, a total body bone scan, a chest radiograph, and a CT of the pelvis.
. MRI of the thigh, a total body bone scan, a chest radiograph, and a CT of the abdomen and pelvis.
. a CT of the chest and thigh, a total body bone scan, and a chest radiograph.

Correct Answer & Explanation

. MRI and a radiograph of the thigh and CT of the chest.

Explanation

The appropriate staging studies should consist of MRI and a radiograph of the primary lesion and CT of the chest. MRI is superior to CT for soft-tissue imaging. CT may be useful for evaluating the cortex of bone for invasion by tumor. Bone scans are not commonly used because soft-tissue sarcomas rarely metastasize to bone. CT of the abdomen and pelvis is not typically ordered except for possible liposarcoma. With liposarcoma, there may be a synchronous or metastatic retroperitoneal liposarcoma. Demetri GD, Pollock R, Baker L, et al: NCCN sarcoma practice guidelines: National Comprehensive Cancer Network. Oncology (Huntingt) 1998;12:183-218.

Question 2066

Topic: 10. Pathology and Oncology

A 15-year-old girl has left knee pain and an enlarging mass in the distal thigh. AP and lateral radiographs are shown in Figures 52a and 52b, and a biopsy specimen is shown in Figure 52c. What is the most likely diagnosis?

. Osteosarcoma
. Ewing's sarcoma
. Chondrosarcoma
. Metastatic neuroblastoma
. Osteochondroma

Correct Answer & Explanation

. Osteosarcoma

Explanation

A bone-producing lesion in the metaphysis of an adolescent is most likely an osteosarcoma. The radiographs show a distal femoral bone-producing lesion extending into the surrounding soft tissues. The histologic appearance consists of pleomorphic cells producing osteoid. Ewing's sarcoma and metastatic neuroblastoma do not produce a matrix. Chondrosarcoma is a radiographically destructive lesion with calcification and cartilage cells on histologic section. An osteochondroma is a benign cartilage lesion that is continuous with the medullary cavity of the underlying bone and extends into a bony lesion and covered by a cartilage cap. Unni KK: Dahlin's Bone Tumors: General Aspects and Data on 11,087 Cases, ed 5. Philadelphia, PA, Lippincott-Raven, 1996, pp 143-160.

Question 2067

Topic: 10. Pathology and Oncology

Figures 19a and 19b show the AP and lateral radiographs of an 18-year-old man who has had knee pain for 3 months. Figure 19c shows a histopathologic photomicrograph of the biopsy specimen. Which of the following factors is most likely to affect his survival?

. The decision to proceed with limb-sparing surgery instead of amputation
. The presence of a mutated p53 gene
. Pulmonary nodules detected on a CT scan
. Location of the tumor
. Tumor necrosis of 99% following preoperative chemotherapy

Correct Answer & Explanation

. Pulmonary nodules detected on a CT scan

Explanation

The presence of metastatic disease at diagnosis is the most significant prognostic factor in a patient with osteosarcoma. Limb-sparing surgery, when compared with amputation, is not noted to be associated with any difference in the rate of survival. The presence of a mutated p53 gene has been noted in a minority of patients with osteosarcoma; however, the prognostic importance on an individual basis is unclear. Tumor location and a relative poor response to chemotherapy would be secondary to the presence of metastatic disease in estimating a patient's prognosis. Weis L: Common malignant bone tumors: Osteosarcoma, in Simon MA, Springfield DS (eds): Surgery for Bone and Soft Tissue Tumors. Philadelphia, PA, Lippincott-Raven, 1998, pp 265-274.

Question 2068

Topic: 10. Pathology and Oncology

A 25-year-old man has had an insidious onset of left hip pain over the past 11 months. A radiograph, coronal MRI scan, and histopathologic specimens are seen in Figures 2a through 2d. What is the most likely diagnosis?

. Metastatic lung cancer
. Osteomyelitis
. Osteosarcoma
. Ewing's sarcoma
. Eosinophilic granuloma

Correct Answer & Explanation

. Ewing's sarcoma

Explanation

Ewing's sarcoma is the second most common primary sarcoma of bone in children and young adults. It is a malignant round cell tumor with uncertain histogenesis. Sheets of uniform small round blue cells with a high nuclear-to-cytoplasm ratio and the absence of osteoid formation differentiate this histologic diagnosis from the other conditions. Immunohistochemical staining and molecular diagnostic studies are useful to verify the diagnosis.

Question 2069

Topic: 10. Pathology and Oncology

A 14-year-old girl has had progressive heel pain for the past several months. Based on the radiograph, MRI scan, and biopsy specimens shown in Figures 37a through 37d, treatment should include

. observation.
. wide resection.
. radiation therapy.
. extended curettage.
. chemotherapy.

Correct Answer & Explanation

. extended curettage.

Explanation

An aneurysmal bone cyst is a benign, locally destructive lesion of bone. Most are seen in patients in the second decade of life. The clinical presentation varies, but most patients have pain, tenderness, swelling, and/or pathologic fracture. Radiographs show a radiolucent lesion sometimes with expansile remodeling of the cortex. MRI best detects the commonly seen fluid-fluid levels associated with this lesion. Histologic findings include blood-filled spaces with bland fibrous connective tissue septa. The stroma has histiocytes, fibroblasts, scattered giant cells, hemosiderin, and occasional inflammatory cells. Treatment of these lesions consists of extended curettage, plus or minus the use of adjuvants (liquid nitrogen, phenol, argon beam coagulation), and finally filling the bone void (allograft or other bone substitute). Gibbs CP Jr, Hefele MC, Peabody TD, et al: Aneurysmal bone cyst of the extremities: Factors related to local recurrence after curettage with a high-speed burr. J Bone Joint Surg Am 1999;81:1671-1678.

Question 2070

Topic: 10. Pathology and Oncology

A 21-year-old man with neurofibromatosis and multiple cutaneous neurofibromas has a rapidly enlarging painless mass on his buttock. Examination reveals a nontender, well-defined 6- x 6-cm soft-tissue mass that is deep to the fascia. The best course of action should be to order

. MRI of the buttock.
. CT of the buttock.
. a needle biopsy.
. an incisional biopsy.
. an excisional biopsy.

Correct Answer & Explanation

. MRI of the buttock.

Explanation

Patients with neurofibromatosis are at risk for development of soft-tissue sarcomas (most commonly malignant peripheral nerve sheath tumors). Clinical indications of development of a neurofibrosarcoma include a rapidly enlarging soft-tissue mass; therefore, this patient should be considered to have a neurofibrosarcoma until proven otherwise. MRI is superior to CT in characterizing the anatomic location of soft-tissue masses and the signal characteristics of the lesion. Areas of necrosis within the tumor may be apparent on MRI that cannot be appreciated on CT, suggesting a malignant tumor. Local imaging studies of suspected malignant tumors should be performed prior to needle or open biopsy so that the biopsy site can be excised at the time of definitive resection. Additionally, postbiopsy changes may lead to MRI artifacts that alter the interpretation of the MRI. Demas BE, Heelan RT, Lane J, Marcove R, Hajdu S, Brennan MF: Soft-tissue sarcomas of the extremities: Comparison of MR and CT in determining the extent of disease. Am J Roentgenol 1988;150:615-620.

Question 2071

Topic: 10. Pathology and Oncology

Figures 47a through 47f show the AP radiograph, bone scan, CT scan, MRI scan, and biopsy specimens of a 30-year-old woman who has had vague left shoulder pain for 1 year. Management should consist of

. curettage.
. radiation therapy.
. radiation therapy and chemotherapy.
. antibiotics.
. wide resection.

Correct Answer & Explanation

. curettage.

Explanation

The histology shows eosinophils with a background of larger cells (Langerhans' cells). This is consistent with eosinophilic granuloma. Localized sites are best treated with curettage, steroid injection, or observation. Chemotherapy is used only if there is systemic involvement. Mirra JM: Eosinophilic granuloma, in Bone Tumors: Clinical, Radiologic, and Pathologic Correlations. London, England, Lea and Febiger, 1989, pp 1023-1060. Sessa S, Sommelet D, Lascombes P, Prevot J: Treatment of Langerhans-cell histiocytosis in children: Experience at the Children's Hospital of Nancy. J Bone Joint Surg Am 1994;76:1513-1525.

Question 2072

Topic: 10. Pathology and Oncology

A 35-year-old man has atraumatic painless limited elbow motion. Radiographs are shown in Figures 33a and 33b. What is the most likely diagnosis?

. Melorheostosis
. Ectopic bone formation
. Bone infarct
. Infection
. Juxacortical chondroma

Correct Answer & Explanation

. Melorheostosis

Explanation

Based on the radiographic findings, the patient has melorheostosis, a rare, benign connective tissue disorder that is characterized by a cortical thickening of bone. It produces a "dripping candle wax" appearance with dense hyperostosis that flows along the cortex. Ectopic bone formation is a consideration but is associated with injuries or burns. Bone infarcts produce intraosseous sclerosis typically affecting the distal femur with the "smoke up chimney" appearance. Infection is always a consideration but typically does not have the linear osteitis seen in melorheostosis. Juxacortical chondroma is a benign cartilage growth that arises from the capsule and may involve the underlying cortical bone but rarely the medullary canal. Campbell CJ, Papademetriou T, Bonfiglio M: Melorheostosis: A report of the clinical, roentgenographic, and pathological findings in fourteen cases. J Bone Joint Surg Am 1968;50:1281-1304.

Question 2073

Topic: 10. Pathology and Oncology

A 47-year-old woman has an asymptomatic pelvic mass that was discovered on routine gynecologic examination. A radiograph, CT scan, MRI scan, and biopsy specimen are shown in Figures 7a through 7d. Metastatic work-up is negative. Treatment should consist of

. observation.
. primary wide resection.
. intralesional curettage.
. radiation therapy.
. preoperative chemotherapy.

Correct Answer & Explanation

. primary wide resection.

Explanation

The imaging studies show a chondrosarcoma; therefore, surgical treatment is indicated. There is no role for intralesional treatment of an exophytic lesion, particularly in the pelvis. Even obtaining a biopsy specimen risks intrapelvic contamination, although many surgeons would still perform a biopsy prior to a resection to confirm the diagnosis. Chondrosarcoma is considered resistant to both radiation therapy and chemotherapy; therefore, radiation therapy generally is not used except for unresectable lesions. Chemotherapy would be used only for metastatic disease or in patients with high-grade chondrosarcoma. The grade would not be known until after resection, and in this patient, the histology slide showed a grade I neoplasm. Chemotherapy would not be used preoperatively because a cartilage tumor is unlikely to shrink, and in this patient, the lesion is resectable. Springfield DS, Gebhardt MS, Mcguire MH: Chondrosarcoma: A review. J Bone Joint Surg Am 1996;78:141-149.

Question 2074

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

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.

Question 2075

Topic: 10. Pathology and Oncology

A 40-year-old man reports an enlarging soft-tissue mass in his right shoulder. Based on the MRI scan and biopsy specimens shown in Figures 40a through 40c, what is the most likely diagnosis?

. Nodular fasciitis
. Fibrosarcoma
. Intramuscular hemangioma
. Schwannoma
. Rhabdomyoma

Correct Answer & Explanation

. Nodular fasciitis

Explanation

Nodular fasciitis is a pseudosarcomatous, self-limiting reactive process composed of fibroblasts and myofibroblasts. Most patients give a history of a rapidly growing mass that has been present for only a few weeks. Many have pain associated with the mass and can recall a specific traumatic event predating the presence of the lesion. It can occur at any age but is most commonly seen in adults who are 20 to 40 years of age. Histologically, the lesion is composed of predominantly plump, immature-appearing fibroblasts that bear a close resemblance to the fibroblasts found in granulation tissue. Characteristically, the fibroblasts are arranged in short, irregular bundles and fascicles and are adjacent to collagen and reticulin. The lesions can appear to be more myxoid or more fibrotic in nature and this correlates to the duration of symptoms. The lesions with a short duration of symptoms have a more myxoid appearance in contrast to those of longer duration characterized by hyaline fibrosis. Weiss SW, Goldblum JR, Enzinger FM: Enzinger and Weiss's Soft Tissue Tumors, ed 4. Philadelphia, PA, Elsevier, 2001, pp 250-266.

Question 2076

Topic: 10. Pathology and Oncology

A 28-year-old woman has left shoulder pain and a tender soft-tissue mass. Based on the MRI scan and biopsy specimens shown in Figures 74a through 74c, what is the most likely diagnosis?

. Malignant fibrous histiocytoma
. Lymphoma
. Synovial sarcoma
. Schwannoma
. Neurofibroma

Correct Answer & Explanation

. Schwannoma

Explanation

Schwannomas (neurilemomas) occur at all ages but are most frequently seen in persons between the ages of 20 and 50 years. MRI features of schwannomas are fairly nonspecific, but when they are associated with a large named nerve, the identification of a mass in continuity with that nerve is highly suggestive of a schwannoma. Most have a fairly homogeneous appearance with a high water content and often fusiform shape. Classically, the histology shows alternating Antoni A (dense spindle cell region) areas and Antoni B (loose myxoid tissue) areas. They also demonstrate uniform intense immunostaining with S-100 protein. Damron TA, Sim FH: Soft-tissue tumors about the knee. J Am Acad Orthop Surg 1997;5:141-152.

Question 2077

Topic: 10. Pathology and Oncology

A 10-year-old boy has a painful thigh mass. A radiograph, MRI scan, and biopsy specimen are shown in Figures 42a through 42c. What is the most likely diagnosis?

. Infection
. Parosteal osteosarcoma
. Chondroblastic osteosarcoma
. Chondrosarcoma
. Osteochondroma

Correct Answer & Explanation

. Chondroblastic osteosarcoma

Explanation

A destructive mixed lytic and blastic metaphyseal lesion with a large soft-tissue mass in an adolescent is most likely an osteosarcoma until proven otherwise. The epicenter of the tumor is on the surface of the bone, most likely involves the periosteum, and is more likely to be chondroblastic in nature. Parosteal osteosarcoma is a low-grade tumor, much more radiodense, usually smaller, and found in the posterior distal femur of middle-aged patients. Chondrosarcomas are distinctly rare in childhood.

Question 2078

Topic: 10. Pathology and Oncology

A 15-year-old boy has a mass at the knee. Radiographs show an aggressive tumor involving the proximal tibia, and biopsy findings reveal a high-grade osteosarcoma. Staging studies show that the tumor impinges on the neurovascular bundle. The tumor enlarges during preoperative chemotherapy. Management should now consist of

Pediatrics 2007 Practice Questions: Set 1 (Solved) - Figure 26

. prolonged chemotherapy.
. radiation therapy.
. amputation.
. marginal excision, sparing the neurovascular bundle.
. wide excision, including the neurovascular bundle.

Correct Answer & Explanation

. wide excision, including the neurovascular bundle.

Explanation

Limb salvage procedures have become the usual treatment for even high-grade osteosarcomas. However, tumors associated with pathologic fracture, tumors encasing the neurovascular bundle, and tumors that enlarged during preoperative therapy and are adjacent to the neurovascular bundle require amputation.

Question 2079

Topic: 10. Pathology and Oncology

Radiographs of a pediatric patient reveal a suspected osteosarcoma of the distal femur. Additional staging studies should consist of

. a radiograph and CT of the chest and a bone scan.
. a radiograph and MRI of the primary tumor.
. CT of the abdomen and pelvis.
. CT of the abdomen, chest, and pelvis, radiographs of the chest and primary tumor, MRI of the primary tumor, and a bone scan.
. CT of the chest, radiographs of the chest and primary tumor, MRI of the primary tumor, and a bone scan.

Correct Answer & Explanation

. CT of the chest, radiographs of the chest and primary tumor, MRI of the primary tumor, and a bone scan.

Explanation

CT of the abdomen and pelvis is not part of the staging of osteosarcoma. Staging studies should consist of CT of the chest, radiographs of the chest and primary tumor, MRI of the primary tumor, and a bone scan. The MRI should be obtained prior to the biopsy.

Question 2080

Topic: Soft Tissue Tumors & Metastasis

A 35-year-old woman who is a recreational runner reports posterior knee pain and tightness in the knee with flexion during running. She denies any history of trauma. Examination reveals normal patellar glide and tilt and no patellar apprehension. Range of motion is 5 degrees to 120 degrees, and quadriceps function and knee ligamentous examination are normal. Radiographs are normal. An MRI scan is shown in Figure 18. What is the most likely diagnosis?

Sports Medicine 2007 Practice Questions: Set 3 (Solved) - Figure 8

. Baker's cyst
. Torn medial meniscus
. Patellofemoral pain syndrome
. Lipoma
. Ganglion cyst of the cruciates

Correct Answer & Explanation

. Ganglion cyst of the cruciates

Explanation

Ganglia involving the cruciate ligaments have been recently reported as a cause of knee pain that interferes with knee flexion and extension. The symptoms are poorly localized in this patient and not along the medial joint line, making the diagnosis of a torn medial meniscus less likely. In addition, the MRI findings do not show a significant medial meniscal lesion. A Baker's cyst is usually posteromedial and extends posterior to the interval between the medial head of the gastrocnemius and semimembranosus. MRI scans show a fluid-filled lesion with an increased signal on T1- and T2-weighted images. A lipoma would be bright on the T1-weighted image only. Deutsch A, Veltri DM, Altchek DW, et al: Symptomatic intraarticular ganglia of the cruciate ligaments of the knee. Arthroscopy 1994;10:219-223.

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