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10. Pathology and Oncology MCQs

Practice Set 102 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 2021

Topic: 10. Pathology and Oncology

A 14-year-old boy has an asymptomatic mass on the right arm. MRI scans and biopsy specimens are shown in Figures 51a through 51d. Immunostaining is positive for desmin. Additional staging studies should include

. a bone scan and thallium scan.
. a regional lymph node and bone marrow biopsy.
. MRI of the brain.
. intravenous pyelogram and renal ultrasound.
. parathyroid hormone and serum calcium levels.

Correct Answer & Explanation

. a regional lymph node and bone marrow biopsy.

Explanation

The patient has rhabdomyosarcoma. Axilliary node and bone marrow biopsy are part of the staging because about 12% of patients with rhabdomyosarcoma of the extremity have evidence of lymph nodes metastases at presentation. Bone marrow metastases have been shown to portend a worse prognosis. Lawrence W, Jr., Hays DM, Heyn R, Tefft M, Crist W, Beltangady M, et al: Lymphatic metastases with childhood rhabdomyosarcoma: A report from the Intergroup Rhabdomyosarcoma Study. Cancer 1987;60:910-915.

Question 2022

Topic: Soft Tissue Tumors & Metastasis

Figures 34a through 34c show an axial proton density (spin echo long TR, short TE) image, a sagittal inversion recovery (STIR) image, and a sagittal T1-weighted (short TR, short TE) image of the left thigh. What is the most likely diagnosis?

. Soft-tissue foreign body
. Lipoma
. Hematoma
. Pyomyositis
. Liposarcoma

Correct Answer & Explanation

. Hematoma

Explanation

The images reveal a region of increased signal within the rectus femoris muscle with mild, ill-defined surrounding edema. The presence of high intensity signal on the T1-weighted image favors acute blood, in this case associated with a rectus femoris muscle tear or fatty tissue. However, because of fat suppression, a fatty lesion or lipoma would be dark on STIR, rather than bright as in this image. Most foreign bodies are low intensity signal and if small, are difficult to evaluate with MRI. The lack of adjacent subcutaneous soft-tissue edema or surrounding fluid makes pyomyositis an unlikely diagnosis.

Question 2023

Topic: 10. Pathology and Oncology

A 56-year-old woman has a painful mass on the bottom of her left foot, and orthotic management has failed to provide relief. Examination reveals that the mass is contiguous with the plantar fascia. An MRI scan shows a homogenous nodule within the plantar fascia. Resection of the tumor is shown in the clinical photograph in Figure 39. What type of cell is most likely responsible for the formation of this tumor?

Foot & Ankle Board Review 2006: High-Yield MCQs (Set 4) - Figure 10

. Myocyte
. T-cell
. Synovial cell
. Osteocyte
. Fibromyoblast

Correct Answer & Explanation

. Fibromyoblast

Explanation

The history, examination, and surgical findings are most consistent with plantar fibromatosis. Plantar fibromatosis is a benign tumor of the plantar fascia that consists chiefly of fibromyoblasts. These cells produce excessive collagen and are similar to the cells found in the palmar fascia of patients with Dupuytren's contracture of the hand. The myocyte, synovial cell, and osteocyte all produce their respective individual tissue types but do not contribute to the formation of a plantar fibromatosis. The T-cell is an important immunologic cell that is most affected in patients with HIV.

Question 2024

Topic: 10. Pathology and Oncology

Figures 10a through 10c show the plain radiograph and MRI scans of a 41-year-old man who has right hip pain. What is the most likely diagnosis?

. Giant cell tumor
. Rheumatoid arthritis
. Metastatic carcinoma
. Osteonecrosis
. Transient osteoporosis

Correct Answer & Explanation

. Transient osteoporosis

Explanation

Transient osteoporosis is a self-limited painful but reversible disorder. Although first described in pregnant women, it is more common in young to middle-aged men. The radiograph shows loss of mineralization in the right hip relative to the left side. There is no osseous destruction or cortical expansion typical of metastasis or giant cell tumor. The process is confined to the femoral side of the joint unlike rheumatoid arthritis, which would be centered in the joint. Osteonecrosis is better defined with sharp but irregularly shaped margins, and there is no double-line sign. The MRI scans reveal diffuse edema in the femoral head and neck that is atypical for osteonecrosis. Transient osteoporosis may recur in the same or opposite hip.

Question 2025

Topic: 10. Pathology and Oncology

Figures 63a and 63b show the radiographs of an 11-year-old girl who sustained a twisting injury of the knee playing soccer. She is now asymptomatic. What is the appropriate treatment of the lesion?

. Needle biopsy
. Incisional biopsy
. Observation
. Curettage and grafting
. Chemotherapy and en bloc resection

Correct Answer & Explanation

. Observation

Explanation

This is a nonossifying fibroma of the proximal tibia. The lesion is eccentric, cortically based, with sclerotic margins and no evidence of a soft-tissue mass. Nonossifying fibromas are benign lesions that need no biopsy or surgical treatment when classic findings appear on radiographs. A follow-up radiograph should be performed 2 to 3 months after the initial presentation to ensure that the lesion is not progressive. Surgery is reserved for large lesions with risk of pathologic fracture or for cases where a displaced pathologic fracture has occurred and internal fixation is needed for fracture treatment. Nondisplaced pathologic fractures through nonossifying fibromas are best treated by allowing the fracture to heal and observation of the lesion. Vaccaro AR (ed): Orthopaedic Knowledge Update 8. Rosemont, IL, American Academy of Orthopaedic Surgeons, 2005, pp 197-215.

Question 2026

Topic: 10. Pathology and Oncology

Figures 52a and 52b show the plain radiographs of a 12-year-old girl who has right distal leg pain. She reports that symptoms are present with weight-bearing activities and improve with rest. Examination reveals diffuse tenderness over the distal tibial metaphysis and mild swelling. A photomicrograph of the biopsy specimen is shown in Figure 52c. What is the most likely diagnosis?

. Giant cell tumor
. Aneurysmal bone cyst
. Unicameral bone cyst
. Eosinophilic granuloma
. Ewing's sarcoma

Correct Answer & Explanation

. Giant cell tumor

Explanation

This lytic lesion is in the epiphyseal-metaphyseal region of the distal tibia. The most common lesion in this area is a giant cell tumor. Although these lesions are most commonly seen in adults, they can also occur in the skeletally immature patient. The photomicrograph shows a lesion with multiple giant cells, the nuclei of which are similar to those in the background stroma; this finding is characteristic of giant cell tumors. Giant cells can be seen in many benign lesions, including aneurysmal bone cysts, Brown tumors, and eosinophilic granuloma. These lesions usually have fewer giant cells with less nuclei. The location of this lesion in the epiphyseal-metaphyseal area is not seen in aneurysmal bone cysts, unicameral bone cysts, Ewing's sarcoma, or eosinophilic granuloma.

Question 2027

Topic: 10. Pathology and Oncology

The scoring system for impending pathologic fractures devised by Mirels involves assessment of which of the following factors?

Basic Science Board Review 2008: High-Yield MCQs (Set 2) - Figure 18

. Lesion location, amount of pain, lesion type, lesion size (lucent/blastic)
. Patient's functional status, lesion location, amount of pain, lesion size
. Lesion type (lucent/blastic), patient's functional status, lesion location, amount of pain
. Lesion size, lesion type (lucent/blastic), lesion location, patient's functional status
. Amount of pain, patient's functional status, lesion type (lucent/blastic), lesion size

Correct Answer & Explanation

. Lesion location, amount of pain, lesion type, lesion size (lucent/blastic)

Explanation

The scoring system published by Mirels in 1989 is based on the following characteristics: the location of the lesion, the amount of pain the patient is experiencing, the type of lesion (either lucent, mixed, or blastic), and the lesion size. The tumor is scored from 1 to 3 in each category and a total score is obtained that correlates to fracture risk. Prophylactic fixation is advised for lesions with scores of higher than 8, and consideration for stabilization should be strongly considered for scores of 8. The Mirels scoring system can be useful as an adjunct to clinical decision making. Mirels H: Metastatic disease in long bones: A proposed scoring system for diagnosing impending pathologic fractures. 1989. Clin Orthop Relat Res 2003;415:S4-S13.

Question 2028

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?

Basic Science Board Review 2008: High-Yield MCQs (Set 2) - Figure 28

. X-linked
. Autosomal recessive
. Autosomal dominant
. Mitochondral inheritance
. Germline mutation

Correct Answer & Explanation

. Autosomal dominant

Explanation

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. Stieber JR, Dormans JP: Manifestations of hereditary multiple exostoses. J Am Acad Orthop Surg 2005;13:110-120.

Question 2029

Topic: 10. Pathology and Oncology

Figures 11a and 11b show the AP and lateral radiographs of a 32-year-old patient on hemodialysis who has increasing elbow pain and a visibly growing mass over the extensor surface. Figure 11c shows the photomicrograph of the biopsy specimen. What is the most likely diagnosis?

. Myositis ossificans
. Tumoral calcinosis
. Synovial cell sarcoma
. Fungal granuloma
. Hemochromatosis

Correct Answer & Explanation

. Tumoral calcinosis

Explanation

The radiographic findings are classic for tumoral calcinosis; they are not consistent with myositis ossificans, fungal granuloma, or hemochromatosis. The condition typically appears as large aggregations of dense calcified lobules confined to the surrounding soft tissues. Hyperphosphatemia is a fundamental factor in many patients with this condition. Tumoral calcinosis also occurs in the setting of chronic renal failure when mineral homeostasis is not controlled. The histologic appearance is essentially a foreign body granuloma reaction. Multilocular cysts with purplish amorphous material are surrounded by thick connective tissue capsules. The fibrous walls contain numerous foreign body giant cells. Surgical excision is indicated if the tumor causes discomfort or interferes with function. Sisson HA, Murray RO, Kemp HBS (eds): Orthopaedic Diagnosis: Clinical, Radiological and Pathological Coordinates. New York, NY, Springer-Verlag, 1984.

Question 2030

Topic: Bone Tumors

Figure 15a shows the radiograph of a patient who has a chondrosarcoma of the acetabulum. Bone scans are shown in Figures 15b and 15c. Numerous soft subcutaneous masses are present. A clinical photograph of the hand is shown in Figure 15d. What is the most likely diagnosis?

. Multiple hereditary exostosis
. Ollier's disease
. Maffucci's syndrome
. McCune-Albright syndrome
. Neurofibromatosis

Correct Answer & Explanation

. Maffucci's syndrome

Explanation

Chondrosarcomas associated with diffuse bone lesions (enchondromas) are characteristic of Ollier's disease. When accompanied by subcutaneous masses (hemangiomas), the condition is called Maffucci's syndrome. Multiple hereditary exostosis is characterized by diffuse osteochondromas. McCune-Albright syndrome is characterized by polyostotic fibrous dysplasia with cafe-au-lait spots and precocious puberty. Neurofibromatosis can have associated bone lesions but is not associated with chondrosarcomas. Sun TC, Swee TC: Chondrosarcoma in Maffucci's syndrome. J Bone Joint Surg Am 1985;67:1214-1219. Schwartz HS, Zimmerman NB, Simon MA, et al: The malignant potential of enchondromatosis. J Bone Joint Surg Am 1987;69:269-274.

Question 2031

Topic: 10. Pathology and Oncology

A 10-month-old boy has multiple skeletal lesions and a skin rash that he has had since he was a newborn. Based on the radiographs and biopsy specimens shown in Figures 79a through 79d, what is the most likely diagnosis?

. Osteomyelitis
. Langerhan's cell histiocytosis
. Ewing's sarcoma
. Lymphoma
. Neuroblastoma

Correct Answer & Explanation

. Langerhan's cell histiocytosis

Explanation

Langerhans cell histiocytosis or eosinophilic granuloma is a nonneoplastic lesion that is part of a spectrum of clinical diseases featuring histiocytes. Most occur during the first two decades of life within any bone. Radiographs show a radiolucent lesion, frequently diaphyseal in location. A periosteal response is occasionally seen and can resemble more aggressive lesions such as osteomyelitis or Ewing's sarcoma. Histology demonstrates CD1a positive histiocytes with large oval-shaped nuclei with indentation, and a variable presence of eosinophils. Plasschaert F, Craig C, Bell R, et al: Eosinophilic granuloma: A different behaviour in children than in adults. J Bone Joint Surg Br 2002;84:870-872.

Question 2032

Topic: 10. Pathology and Oncology

A 45-year-old woman has had radiating pain in the medial ankle for the past 3 months. Examination reveals a small mass in the retromedial ankle region and a positive Tinel's sign. An intraoperative photograph and a hematoxylin/eosin biopsy specimen are shown in Figures 24a and 24b. Treatment should consist of

. chemotherapy.
. radiation therapy.
. marginal excision.
. wide excision.
. above-knee amputation.

Correct Answer & Explanation

. marginal excision.

Explanation

Neurilemoma is a benign tumor of nerve sheath origin, and peak incidence is in the third through sixth decades. The tumor is well encapsulated on the surface of a peripheral nerve. MRI findings may be significant for a "string sign." A positive Tinel's sign in the distribution of the nerve affected may be present. Grossly, the lesion is well encapsulated in a nerve sheath. Microscopically, there are structures referred to as Antoni A (a pattern of spindle cells arranged in intersecting bundles) and Antoni B (areas with less cellularity with loosely arranged cells). These lesions are benign, and treatment should consist of marginal excision. Nerve function may be preserved by careful dissection, excising the lesion parallel to the nerve fascicles so the lesion may be extruded. Recurrence is rare. Walling AK: Soft tissue and bone tumors, in Coughlin MJ, Mann RA (eds): Surgery of the Foot and Ankle, ed 7. St Louis, MO, Mosby, 1999, pp 1007-1032.

Question 2033

Topic: 10. Pathology and Oncology

A 17-year-old boy has had a mass in his right thigh for the past 6 months. He denies any history of trauma. Examination reveals that the mass is painless and firm. A radiograph and axial MRI scan are shown in Figures 49a and 49b. What is the most likely diagnosis?

. Osteochondroma
. Osteosarcoma
. Periosteal chondroma
. Ewing's sarcoma of bone
. Chondroblastoma

Correct Answer & Explanation

. Osteochondroma

Explanation

Osteochondroma typically occurs as a bony projection or a sessile growth on the bone, and there can be flaring of the metaphysis. The radiograph shows continuity from the adjacent cancellous bone into the lesion itself. There is no soft-tissue mass or bone destruction to suggest osteosarcoma or Ewing's sarcoma. Periosteal chondroma has a scalloped out radiographic appearance. Chondroblastoma typically is an epiphyseal-based lesion.

Question 2034

Topic: 10. Pathology and Oncology

What is the most common pediatric soft-tissue sarcoma?

Basic Science 2002 Practice Questions: Set 1 (Solved) - Figure 41

. Ewing's sarcoma
. Liposarcoma
. Rhabdomyosarcoma
. Malignant fibrous histiocytoma
. Fibrosarcoma

Correct Answer & Explanation

. Rhabdomyosarcoma

Explanation

Soft-tissue sarcomas are the sixth most common cancer in children. Rhabdomyosarcoma is the most common type of pediatric soft-tissue sarcoma. Nearly 50% of rhabdomyosarcomas are diagnosed in children who are age 5 years or younger. Unfortunately, there has not been a significant increase in survival in children with metastatic rhabdomyosarcoma despite aggressive therapy including multiple-drug chemotherapy regimens.

Question 2035

Topic: 10. Pathology and Oncology

A 26-year-old man has had hand pain and progressive swelling in the knuckle for the past several months. He denies any trauma to the hand. The ring finger metacarpophalangeal joint is tender, and there is loss of motion in the digit. Figure 32a shows the radiograph and Figures 32b through 32d show the T1-weighted, T2-weighted, and gadolinium MRI scans, respectively. What is the most likely diagnosis?

. Infection
. Giant cell tumor
. Nonossifying fibroma
. Enchondroma
. Osteosarcoma

Correct Answer & Explanation

. Giant cell tumor

Explanation

The radiograph reveals a subchondral lesion in the metacarpophalangeal joint that is lytic and expansile. The MRI scans show a mass that is moderate in intensity on the T2-weighted image and has some gadolinium uptake. There are no cystic components in this lesion. The subchondral location and expansile nature are highly suggestive of giant cell tumor of bone. A lesion with this appearance might also represent an aneurysmal bone cyst, given the amount of expansion present. Menendez LR (ed): Orthopaedic Knowledge Update: Musculoskeletal Tumors. Rosemont, IL, American Academy of Orthopaedic Surgeons, 2002, pp 113-118.

Question 2036

Topic: 10. Pathology and Oncology

A patient undergoes a simple excision of a 3-cm superficial mass in the thigh at another institution. The final pathology reveals a leiomyosarcoma, without reference to the margins. What is the recommendation for definitive treatment?

Basic Science Board Review 2008: High-Yield MCQs (Set 2) - Figure 50

. Repeat wide excision of the tumor bed
. Observation
. Radiation therapy to the tumor bed only
. Chemotherapy
. Radiation therapy and chemotherapy

Correct Answer & Explanation

. Repeat wide excision of the tumor bed

Explanation

Treatment of patients with unplanned excision of soft-tissue sarcomas is challenging. If the margins are positive or unclear, the patient is best managed with repeat excision of the tumor bed, and radiation therapy if the repeat excision does not yield wide margins. In patients with no detectable tumor on physical examination or imaging after unplanned excision, some studies have shown that up to 35% of patients will have residual disease and a poorer local recurrence rate (22% versus 7%). Therefore, whenever feasible, a reexcision of the tumor bed is recommended.

Question 2037

Topic: 10. Pathology and Oncology

A 46-year-old woman has bilateral groin pain, with more severe pain on the left side than on the right side. Figures 44a and 44b show a radiograph and a T1-weighted MRI scan. What is the most likely diagnosis?

. Rheumatoid arthritis
. Osteoarthritis
. Metastatic carcinoma
. Osteonecrosis
. Gout

Correct Answer & Explanation

. Osteonecrosis

Explanation

The radiograph reveals bilateral patchy sclerosis of the femoral heads without evidence of collapse. The MRI scan shows bilateral head involvement with a common serpentine-like low-intensity signal of the superior femoral head that is common to osteonecrosis. Changes confined to the femoral head effectively exclude rheumatoid arthritis and osteoarthritis. Resnick D (ed): Diagnosis of Bone and Joint Disorders, ed 4. Philadelphia, PA, WB Saunders, 2002, vol 4, pp 3160-3162.

Question 2038

Topic: 10. Pathology and Oncology

Figures 35a and 35b show the axial T2-weighted and coronal T1-weighted MRI scans of a patient who has enlargement of the right thigh. What is the most likely diagnosis?

. Conventional osteosarcoma
. Periosteal osteosarcoma
. Ewing's sarcoma
. Myositis ossificans
. Subperiosteal chondroma

Correct Answer & Explanation

. Periosteal osteosarcoma

Explanation

The images show a large, almost circumferential, mass surrounding the diaphysis of the femur. The intramedullary signal is normal with minimal cortical destruction, both findings that should be abnormal in conventional osteosarcoma and Ewing's sarcoma. There are very low-signal striations representing osteoid formation that would have a sunburst radiographic pattern. This indicates an osteogenic lesion. Myositis ossificans is not indicated because studies would reveal zonal ossification starting in the periphery rather than the more central pattern seen in this patient. This appearance is typical for periosteal osteosarcoma.

Question 2039

Topic: 10. Pathology and Oncology

What is the most common secondary malignancy arising in pagetic bone?

Basic Science 2005 Practice Questions: Set 1 (Solved) - Figure 45

. Fibrosarcoma
. Chondrosarcoma
. Malignant fibrous histiocytoma
. Osteosarcoma
. Ewing's sarcoma

Correct Answer & Explanation

. Osteosarcoma

Explanation

The incidence of malignant transformation or the formation of a secondary malignancy in pagetic bone is estimated to be less than 1%. Osteosarcoma is the most common secondary malignancy, followed by fibrosarcoma and chondrosarcoma. Ewing's sarcoma arising in pagetic bone has not been reported. Grimer RJ, Carter SR, Tillman RM, et al: Osteosarcoma of the pelvis. J Bone Joint Surg Br 1999;81:796-802.

Question 2040

Topic: 10. Pathology and Oncology

A 70-year-old former baseball catcher reports long-standing pain in the ring and little fingers. A gradient-echo MRI scan is shown in Figure 26. What is the most likely diagnosis?

Anatomy Board Review 2005: High-Yield MCQs (Set 2) - Figure 27

. Giant cell tumor of the tendon sheath
. Ulnar artery aneurysm
. Lipoma
. Hematoma
. Neurolemmoma

Correct Answer & Explanation

. Ulnar artery aneurysm

Explanation

The gradient-echo MRI scan highlights the ulnar and radial arteries, as indicated by the arrow. This technique suppresses the signal of the surrounding fat and causes the stationary surrounding tissues to become intermediate in signal intensity. The flowing blood is then easily identified with a bright signal because it does not absorb the radiofrequency pulse. Based on the findings, the diagnosis is an ulnar artery aneurysm, most likely caused by years of repetitive trauma as the result of catching baseballs. Neurolemmoma and giant cell tumor of the tendon sheath would be intermediately enhanced on this image sequence, and the continuity with the ulnar artery, demonstrated here, would not be expected. Lipomas are not enhanced using the gradient-echo technique. The chronic nature of the patient's symptoms is not indicative of a hematoma, and the hematoma would be dark on this imaging sequence since it is stationary tissue. Koman LA, Ruch DS, Patterson Smith B, et al: Vascular disorders, in Green DP, Hotchkiss RN, Pederson WC (eds): Green's Operative Hand Surgery, ed 4. New York, NY, Churchill Livingstone, 1999, vol 2, pp 2254-2302.

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