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10. Pathology and Oncology MCQs

Practice Set 337 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 6721

Topic: Bone Tumors

A 23-year-old man presents with right posterolateral knee pain that is worse at night and relieved by NSAIDs. Imaging and histology are shown. The histologic specimen demonstrates a nidus of vascular, cellular stroma with immature woven bone trabeculae. What is the currently preferred minimally invasive treatment for this lesion?

. Intralesional injection of corticosteroids
. Percutaneous radiofrequency ablation
. Cryotherapy with liquid nitrogen
. Embolization of the feeding vessels
. Radiation therapy

Correct Answer & Explanation

. Percutaneous radiofrequency ablation

Explanation

Correct Answer: BThe clinical presentation (night pain relieved by NSAIDs), radiographic appearance (cortically based lucent nidus with surrounding sclerosis), and histology (vascular stroma with plump osteoblasts and woven bone) are diagnostic of an osteoid osteoma. Percutaneous radiofrequency ablation (RFA), typically performed under CT guidance, has become the preferred and highly successful minimally invasive treatment for most osteoid osteomas.

Question 6722

Topic: 10. Pathology and Oncology

A 70-year-old man presents with left thigh pain and a monoclonal gammopathy. Radiographs and CT (shown) reveal a large lucent lesion in the peritrochanteric region. Following prophylactic internal fixation with a locked intramedullary rod, which of the following adjuvant therapies is most appropriate to decrease the risk of future pathologic fractures in this patient?


. Wide resection and endoprosthetic reconstruction
. Postoperative bisphosphonates and radiation therapy
. Neoadjuvant chemotherapy followed by radiation
. Open curettage and bone grafting
. Isolated radiation therapy without systemic treatment

Correct Answer & Explanation

. Postoperative bisphosphonates and radiation therapy

Explanation

Correct Answer: BThe underlying diagnosis is multiple myeloma. Because the patient has a large lucent lesion in the peritrochanteric region of the left proximal femur, the risk of pathologic fracture is high. Consideration should be given to prophylactic internal fixation with a locked intramedullary rod. Postoperative treatment with bisphosphonates and radiation therapy is indicated to decrease the risk of future pathologic fractures. The lesion does not appear to be a sarcoma requiring wide resection and endoprosthetic reconstruction.

Question 6723

Topic: 10. Pathology and Oncology

A 14-year-old patient presents with anterior knee pain. Imaging and biopsy specimens are shown. The histology demonstrates small round blue cells. Although this tumor frequently occurs in the diaphysis, the imaging demonstrates its presence in which anatomic region of the bone?


. Epiphysis
. Metaphysis
. Apophysis
. Articular cartilage
. Subchondral bone

Correct Answer & Explanation

. Metaphysis

Explanation

Correct Answer: BThe histology shows small round blue cells that are typical of Ewing's sarcoma. Although Ewing's sarcoma frequently occurs in the diaphysis, it can occur in the metaphysis, as demonstrated in the provided imaging studies.

Question 6724

Topic: 10. Pathology and Oncology

A 16-year-old girl is incidentally found to have the proximal femoral lesion shown in the imaging studies. Biopsy is performed. Which of the following histologic descriptions is most characteristic of this patient's diagnosis?


. Small round blue cells forming Homer-Wright rosettes
. Spicules of woven bone without osteoblastic rimming in a bland fibrous background
. Malignant spindle cells producing immature osteoid matrix
. Multinucleated giant cells in a background of mononuclear stromal cells
. Nests of cartilage cells with binucleate forms and myxoid changes

Correct Answer & Explanation

. Spicules of woven bone without osteoblastic rimming in a bland fibrous background

Explanation

Correct Answer: BThe imaging studies demonstrate fibrous dysplasia. 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.

Question 6725

Topic: 10. Pathology and Oncology

A 14-year-old patient presents with anterior knee pain. Imaging and biopsy specimens are shown. The histology demonstrates small round blue cells. Which of the following genetic translocations is most consistently associated with this diagnosis?

. t(11;22)
. t(9;22)
. t(X;18)
. t(12;16)
. t(2;13)

Correct Answer & Explanation

. t(11;22)

Explanation

Correct Answer: AThe imaging studies and histology showing small round blue cells are typical of Ewing's sarcoma. Ewing's sarcoma has been noted to have a consistent genetic translocation t(11;22). Other translocations include t(X;18) for synovial sarcoma and t(12;16) for myxoid liposarcoma.

Question 6726

Topic: 10. Pathology and Oncology

A 16-year-old girl is found to have an asymptomatic proximal femur lesion after a fall, as shown in the imaging studies. Biopsy is performed. Which of the following histologic descriptions is most characteristic of this lesion?

. Small round blue cells with scant cytoplasm.
. Spicules of woven bone without osteoblastic rimming in a bland fibrous background.
. Malignant cells surrounded by osteoid matrix.
. Blood-filled spaces separated by fibrous septa containing giant cells.
. Plump, atypical osteoblasts producing immature woven bone with a central nidus.

Correct Answer & Explanation

. Spicules of woven bone without osteoblastic rimming in a bland fibrous background.

Explanation

Correct Answer: BThe imaging studies are consistent with fibrous dysplasia. The classic histologic finding of fibrous dysplasia is spicules of woven bone without osteoblastic rimming in a bland fibrous background (often described as 'Chinese characters'). Small round blue cells are seen in Ewing's sarcoma, malignant cells with osteoid in osteosarcoma, blood-filled spaces in aneurysmal bone cysts, and a central nidus with plump osteoblasts in osteoid osteoma.

Question 6727

Topic: 10. Pathology and Oncology

A 13-year-old girl presents with a firm mass and pain in her right shoulder. Radiographs and MRI are shown. Biopsy reveals malignant cells surrounded by osteoid. Which of the following is the most likely diagnosis?

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

Correct Answer & Explanation

. Osteosarcoma

Explanation

Correct Answer: CThe patient has osteosarcoma. The radiograph suggests an aggressive primary tumor of bone, and the histology shows malignant cells surrounded by osteoid, which is classic for osteosarcoma. Ewing's sarcoma histologically consists of small round blue cells. Osteochondroma and periosteal chondroma have a different histologic pattern and a less aggressive radiographic appearance.

Question 6728

Topic: 10. Pathology and Oncology

A 35-year-old man presents with atraumatic, painless limited elbow motion. Radiographs are shown. The classic radiographic appearance of this benign connective tissue disorder is best described as:

. 'Smoke up a chimney' appearance.
. 'Sunburst' periosteal reaction.
. 'Dripping candle wax' appearance.
. 'Onion skin' periosteal reaction.
. 'Popcorn' calcification.

Correct Answer & Explanation

. 'Dripping candle wax' appearance.

Explanation

Correct Answer: CBased 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. 'Smoke up a chimney' is associated with bone infarcts, 'sunburst' with osteosarcoma, and 'onion skin' with Ewing's sarcoma.

Question 6729

Topic: 10. Pathology and Oncology
A 15-year-old boy presents with a painful distal femur mass. Radiographs show a destructive lesion with a sunburst periosteal reaction. A core needle biopsy confirms high-grade osteosarcoma. Following neoadjuvant chemotherapy, which of the following defines a favorable histologic response at the time of definitive resection?
. >50% tumor necrosis
. >80% tumor necrosis
. >90% tumor necrosis
. >95% tumor necrosis
. 100% tumor necrosis only

Correct Answer & Explanation

. >90% tumor necrosis

Explanation

A favorable histologic response to neoadjuvant chemotherapy in osteosarcoma is defined as greater than 90% tumor necrosis (Huvos Grade III or IV) at the time of surgical resection. This is strongly correlated with improved overall survival.

Question 6730

Topic: 10. Pathology and Oncology

A 15-year-old boy presents with progressive knee pain. Imaging shows a destructive metaphyseal lesion of the distal femur with a "sunburst" periosteal reaction and a soft tissue mass. Core biopsy confirms high-grade conventional osteosarcoma. What is the standard-of-care treatment protocol?

. Primary transfemoral amputation followed by chemotherapy
. Neoadjuvant chemotherapy, wide surgical resection, and adjuvant chemotherapy
. Wide surgical resection followed by radiation therapy
. Definitive radiation therapy and bisphosphonates
. Isolated limb perfusion with marginal excision

Correct Answer & Explanation

. Neoadjuvant chemotherapy, wide surgical resection, and adjuvant chemotherapy

Explanation

The gold standard treatment for high-grade conventional osteosarcoma involves neoadjuvant chemotherapy to shrink the primary tumor and treat micrometastases, followed by wide surgical resection (limb salvage if feasible) and adjuvant chemotherapy.

Question 6731

Topic: 10. Pathology and Oncology

A 15-year-old boy presents with worsening knee pain and a palpable mass over the distal femur. Radiographs show a mixed lytic and sclerotic lesion in the distal femoral metaphysis with a "sunburst" periosteal reaction. Biopsy confirms high-grade intramedullary osteosarcoma. Which of the following genetic mutations is most strongly associated with the pathogenesis of this tumor?

. A) t(11;22) translocation
. B) EXT1 mutation
. C) RB1 mutation
. D) GNAS mutation
. E) t(X;18) translocation

Correct Answer & Explanation

. C) RB1 mutation

Explanation

Correct Answer: COsteosarcoma is the most common primary malignant bone tumor in children and adolescents. It is strongly associated with mutations in tumor suppressor genes, most notably the RB1 (retinoblastoma) gene and the TP53 gene (associated with Li-Fraumeni syndrome). Patients with hereditary retinoblastoma (germline RB1 mutation) have a significantly increased risk of developing osteosarcoma later in life. Option A, the t(11;22) translocation, results in the EWS-FLI1 fusion protein and is the hallmark of Ewing sarcoma. Option B, EXT1 (and EXT2) mutations, are associated with hereditary multiple exostoses (osteochondromas). Option D, GNAS mutations, are associated with fibrous dysplasia and McCune-Albright syndrome. Option E, the t(X;18) translocation, is characteristic of synovial sarcoma.

Question 6732

Topic: 10. Pathology and Oncology

A 70-year-old male with a known history of Paget's disease presents with a 2-month history of new, severe, and unrelenting pain in his right thigh. Radiographs reveal a mixed lytic and sclerotic lesion in the mid-diaphysis of the femur with cortical destruction and a soft tissue mass. What is the most likely diagnosis?

. Chondrosarcoma
. Osteosarcoma
. Multiple Myeloma
. Metastatic prostate carcinoma
. Fibrosarcoma

Correct Answer & Explanation

. Osteosarcoma

Explanation

The most feared complication of Paget's disease is malignant transformation, which occurs in about 1% of patients and is most commonly osteosarcoma. This typically presents with new, progressive pain in a previously asymptomatic or stable pagetic bone.

Question 6733

Topic: 10. Pathology and Oncology

A 40-year-old female with a history of recurrent nephrolithiasis presents with a well-circumscribed lytic lesion in her distal femur. Biopsy reveals localized accumulations of giant cells, hemosiderin-laden macrophages, and spindle cells. Laboratory workup shows elevated serum calcium and low serum phosphorus. What is the most likely diagnosis of the bone lesion?

. Giant cell tumor of bone
. Aneurysmal bone cyst
. Chondroblastoma
. Brown tumor (osteitis fibrosa cystica)
. Non-ossifying fibroma

Correct Answer & Explanation

. Brown tumor (osteitis fibrosa cystica)

Explanation

Brown tumors are non-neoplastic, reactive bone lesions caused by primary or secondary hyperparathyroidism, histologically characterized by giant cells and hemosiderin. The laboratory findings of hypercalcemia and hypophosphatemia point to primary hyperparathyroidism as the underlying cause.

Question 6734

Topic: 10. Pathology and Oncology

A 70-year-old man with a long-standing history of enlarged skull and bowed tibias presents with a sudden onset of severe, unrelenting pain in his right proximal femur, which was previously asymptomatic. His serum alkaline phosphatase is notably higher than his baseline.

What is the most likely diagnosis?

. Pathologic insufficiency fracture
. Secondary hyperparathyroidism
. Acute osteomyelitis
. Osteosarcoma
. Metastatic prostate carcinoma

Correct Answer & Explanation

. Osteosarcoma

Explanation

A sudden increase in localized pain, swelling, and a massive spike in alkaline phosphatase in a patient with Paget's disease is highly suspicious for malignant transformation. Osteosarcoma is the most common and aggressive malignancy arising in Pagetic bone.

Question 6735

Topic: 10. Pathology and Oncology

A 74-year-old male with a long-standing history of bone pain and enlarging skull size presents with a new, severe, and unrelenting pain in his right thigh. Radiographs reveal a destructive, lytic lesion with cortical breakthrough in the diaphysis of the femur.

What is the most likely diagnosis?

. Chondrosarcoma
. Ewing sarcoma
. Multiple myeloma
. Osteosarcoma
. Metastatic prostate cancer

Correct Answer & Explanation

. Osteosarcoma

Explanation

The patient has a history consistent with Paget's disease. The most dreaded complication of Paget's disease is malignant transformation, most commonly to secondary osteosarcoma, which typically presents with new unrelenting pain and a destructive lytic lesion.

Question 6736

Topic: 10. Pathology and Oncology

A 45-year-old female presents with diffuse bone pain and a history of recurrent nephrolithiasis. Radiographs demonstrate a lytic lesion in her proximal femur. Biopsy of the lesion reveals spindle cells, multinucleated giant cells, and abundant hemosiderin deposits. Which of the following laboratory profiles is most consistent with her diagnosis?

. Low serum calcium, high parathyroid hormone (PTH), low phosphorus
. Normal serum calcium, normal PTH, elevated alkaline phosphatase
. Elevated serum calcium, elevated PTH, low phosphorus
. Normal serum calcium, low PTH, elevated alkaline phosphatase
. Elevated serum calcium, low PTH, normal phosphorus

Correct Answer & Explanation

. Elevated serum calcium, elevated PTH, low phosphorus

Explanation

The biopsy findings and clinical history (stones, bones) are classic for a Brown tumor associated with primary hyperparathyroidism. Typical laboratory findings include elevated serum calcium, elevated PTH, and low serum phosphorus.

Question 6737

Topic: 10. Pathology and Oncology

A 72-year-old male with a known history of Paget's disease presents with new-onset, severe, and unrelenting left thigh pain. Radiographs demonstrate a destructive lytic lesion in the femur with cortical breakthrough and soft tissue extension.

What is the most likely diagnosis?

. Osteosarcoma
. Chondrosarcoma
. Ewing sarcoma
. Multiple myeloma
. Metastatic prostate carcinoma

Correct Answer & Explanation

. Osteosarcoma

Explanation

Malignant transformation in Paget's disease occurs in about 1% of patients, presenting with new, unrelenting pain. Secondary osteosarcoma is the most common and carries a poor prognosis.

Question 6738

Topic: 10. Pathology and Oncology

A 50-year-old female presents with a pathological fracture of the humerus. Radiographs show a well-defined, expansile, lytic lesion. Labs reveal hypercalcemia, hypophosphatemia, and elevated PTH.

Biopsy of the lesion would most likely show:

. Atypical plasma cells with kappa light chains
. Mononuclear cells and giant cells within a hemorrhagic stroma
. Malignant spindle cells producing osteoid
. Deposition of monosodium urate crystals
. Disorganized cement lines in a mosaic pattern

Correct Answer & Explanation

. Mononuclear cells and giant cells within a hemorrhagic stroma

Explanation

The clinical picture describes primary hyperparathyroidism presenting with a Brown tumor (osteitis fibrosa cystica). Histologically, Brown tumors consist of multinucleated giant cells and mononuclear cells in a highly vascular, hemorrhagic, fibroblastic stroma.

Question 6739

Topic: 10. Pathology and Oncology

An 70-year-old man with a long-standing history of Paget's disease presents with a sudden, progressive increase in thigh pain and swelling. Radiographs show a destructive, permeative lesion in the proximal femur with cortical breakthrough. What is the most common malignant transformation in this patient population?

. Chondrosarcoma
. Osteosarcoma
. Ewing sarcoma
. Multiple myeloma
. Fibrosarcoma

Correct Answer & Explanation

. Osteosarcoma

Explanation

Osteosarcoma is the most common malignant transformation in Paget's disease, occurring in about 1% of patients. It typically presents with a sudden increase in pain and a destructive bone lesion.

Question 6740

Topic: 10. Pathology and Oncology

A 35-year-old woman presents with a pathological fracture of the proximal humerus. Radiographs reveal a large, purely lytic lesion. Laboratory tests demonstrate elevated serum calcium and elevated parathyroid hormone levels. A biopsy of the lesion shows abundant multinucleated giant cells in a fibrovascular stroma with hemosiderin deposition. What is the most appropriate definitive management for the underlying cause of this bone lesion?

. Wide resection of the humeral lesion
. Intralesional curettage and bone grafting alone
. Parathyroidectomy
. Radiation therapy
. Initiation of denosumab

Correct Answer & Explanation

. Parathyroidectomy

Explanation

The patient has a Brown tumor resulting from primary hyperparathyroidism. Definitive treatment involves parathyroidectomy to normalize parathyroid hormone levels, which usually allows the bone lesion to heal spontaneously.

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