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10. Pathology and Oncology MCQs

Practice Set 346 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 6901

Topic: 10. Pathology and Oncology

A 14-year-old boy presents with progressive shoulder pain and weakness. Radiographs show complete osteolysis of the clavicle and acromion without reactive bone formation.

Biopsy is likely to show which of the following histopathologic features?

. Thin-walled vascular and lymphatic channels
. Malignant spindle cells in a herringbone pattern
. Multinucleated giant cells in a hemorrhagic background
. Sheets of monotonous round blue cells
. Prominent woven bone with atypical osteoblastic rimming

Correct Answer & Explanation

. Thin-walled vascular and lymphatic channels

Explanation

Gorham-Stout disease (vanishing bone disease) is characterized by angiomatosis, a benign proliferation of thin-walled vascular or lymphatic channels. This process leads to progressive, massive osteolysis without reactive bone formation.

Question 6902

Topic: 10. Pathology and Oncology

A 15-year-old female presents with a radiolucent, expansile lesion in the proximal phalanx of her index finger. Biopsy shows spindle cells in a fibrous stroma with focal hemorrhage, clustered multinucleated giant cells, and reactive bone formation. Laboratory tests (serum calcium, PTH) are completely normal. What is the most likely diagnosis?

. Giant cell tumor of bone
. Giant cell reparative granuloma
. Brown tumor of hyperparathyroidism
. Aneurysmal bone cyst
. Enchondroma

Correct Answer & Explanation

. Giant cell reparative granuloma

Explanation

Giant cell reparative granuloma (GCRG) commonly affects the small bones of the hands and feet or facial bones in the 2nd decade of life. Normal PTH and calcium levels effectively rule out a brown tumor, which has an identical histologic appearance.

Question 6903

Topic: 10. Pathology and Oncology

A 25-year-old male presents with progressive shoulder weakness and a dull ache. Radiographs show extensive resorption of the humeral head and glenoid without a sclerotic margin or periosteal reaction.

Biopsy reveals thin-walled, endothelium-lined vascular channels replacing bone. What is the most likely diagnosis?

. Giant cell tumor
. Gorham-Stout disease
. Aneurysmal bone cyst
. Essential osteolysis
. Skeletal angiomatosis

Correct Answer & Explanation

. Gorham-Stout disease

Explanation

Gorham-Stout disease (massive osteolysis) is characterized by spontaneous, progressive bone resorption and replacement by non-neoplastic vascular or lymphatic tissue. It classically lacks reactive new bone formation or sclerosis.

Question 6904

Topic: 10. Pathology and Oncology

A 22-year-old female presents with a slowly enlarging, painless swelling over her mandible. Radiographs show a multilocular radiolucent lesion. Histology reveals fibrous stroma with focal hemorrhage, hemosiderin, and clustered multinucleated giant cells around hemorrhagic areas. What is the most likely diagnosis?

. Brown tumor of hyperparathyroidism
. Giant cell tumor of bone
. Aneurysmal bone cyst
. Giant cell reparative granuloma
. Fibrous dysplasia

Correct Answer & Explanation

. Giant cell reparative granuloma

Explanation

GCRG occurs predominantly in the mandible, maxilla, and small bones of the hands/feet. Histologically, it features clustered giant cells around areas of hemorrhage, differing from the diffuse giant cell distribution in true Giant Cell Tumors.

Question 6905

Topic: 10. Pathology and Oncology

A 34-year-old presents with a painful swelling in the 3rd metacarpal. X-rays show a lytic, expansile lesion in the metaphysis. Blood tests reveal normal calcium, phosphorus, and PTH levels. Biopsy shows spindle cells with grouped multinucleated giant cells and zones of reactive bone formation. Which condition must be ruled out before confirming GCRG?

. Osteoid osteoma
. Enchondroma
. Hyperparathyroidism (Brown tumor)
. Multiple myeloma
. Ewing sarcoma

Correct Answer & Explanation

. Hyperparathyroidism (Brown tumor)

Explanation

Brown tumors of hyperparathyroidism are histologically indistinguishable from giant cell reparative granulomas. Normal serum calcium, phosphate, and PTH levels are required to exclude a Brown tumor before diagnosing GCRG.

Question 6906

Topic: 10. Pathology and Oncology

During evaluation of a lytic lesion in the distal phalanx of a 28-year-old patient, histological review shows fibroblasts, areas of hemorrhage, and multinucleated giant cells that are small and clustered irregularly. Which feature is most helpful to differentiate GCRG from true Giant Cell Tumor of Bone (GCTB)?

. Presence of a H3F3A mutation in GCTB
. Presence of woven bone in GCTB
. Higher mitotic rate in GCRG
. Elevated serum alkaline phosphatase in GCRG
. Epiphyseal location of GCRG

Correct Answer & Explanation

. Presence of a H3F3A mutation in GCTB

Explanation

True Giant Cell Tumors of Bone (GCTB) are defined molecularly by the presence of H3F3A histone mutations in the majority of cases. GCRGs lack this mutation, have giant cells clustered near hemorrhage, and occur more frequently in the hands/feet.

Question 6907

Topic: 10. Pathology and Oncology

Which of the following histopathological features most reliably differentiates a Giant Cell Reparative Granuloma (GCRG) from a true Giant Cell Tumor (GCT) of bone?

. Diffuse, uniform distribution of giant cells throughout the stroma.
. Mononuclear stromal cells with identical nuclei to the giant cells.
. Giant cells clustered irregularly around areas of hemorrhage.
. High mitotic rate with atypical figures indicating malignancy.
. Presence of woven bone formation spanning the lesion.

Correct Answer & Explanation

. Giant cells clustered irregularly around areas of hemorrhage.

Explanation

GCRG is a reactive lesion where multinucleated giant cells characteristically cluster around areas of hemorrhage and a spindle cell stroma. In contrast, a true GCT features a uniform distribution of giant cells whose nuclei closely resemble the surrounding mononuclear stromal cells.

Question 6908

Topic: 10. Pathology and Oncology

A 16-year-old female presents with swelling in her right middle finger after a jamming injury 3 months ago. Radiographs show a lytic, expansile lesion in the diaphysis of the proximal phalanx without cortical breakthrough. Biopsy reveals spindle cells and giant cells grouped around hemorrhagic foci. Which of the following is true?

. It requires wide en bloc resection due to high malignant potential.
. The lesion is more commonly found in the epiphysis of long bones.
. It is a benign, reactive process commonly found in the small tubular bones of the hands and feet.
. It is pathognomonic for hyperparathyroidism and systemic testing is required for diagnosis.
. It typically metastasizes to the lungs in 5% of cases.

Correct Answer & Explanation

. It is a benign, reactive process commonly found in the small tubular bones of the hands and feet.

Explanation

Giant Cell Reparative Granuloma (GCRG) is a benign, non-neoplastic reactive process frequently triggered by intraosseous hemorrhage or trauma. It most commonly occurs in the small tubular bones of the hands/feet or the craniofacial skeleton, and is adequately treated with curettage.

Question 6909

Topic: 10. Pathology and Oncology

A 24-year-old male presents with progressive shoulder pain and weakness over two years. Serial radiographs demonstrate progressive 'vanishing' of the proximal humerus without a distinct mass.

A biopsy is performed. What is the expected predominant histologic finding?

. Malignant spindle cells producing osteoid
. Non-neoplastic proliferation of thin-walled vascular and lymphatic channels
. Sheets of uniform mononuclear cells expressing RANKL
. Monoclonal proliferation of plasma cells
. Hyperactive multinucleated giant cells lacking a ruffled border

Correct Answer & Explanation

. Non-neoplastic proliferation of thin-walled vascular and lymphatic channels

Explanation

Gorham-Stout disease (massive osteolysis) is characterized by the benign, non-neoplastic proliferation of thin-walled vascular and lymphatic channels that replace normal bone marrow. This vascular proliferation stimulates aggressive regional bone resorption.

Question 6910

Topic: 10. Pathology and Oncology

A 25-year-old female presents with a lytic, expansile lesion in the 2nd metacarpal. Biopsy demonstrates a spindle cell background with clustered, irregularly distributed multinucleated giant cells centered around areas of hemorrhage. Laboratory workup reveals normal serum calcium and parathyroid hormone levels. What is the most likely diagnosis?

. Giant cell tumor of bone
. Brown tumor of hyperparathyroidism
. Giant cell reparative granuloma
. Aneurysmal bone cyst
. Enchondroma

Correct Answer & Explanation

. Giant cell reparative granuloma

Explanation

Giant cell reparative granuloma (GCRG) classically presents in the small bones of the hands/feet or the jaw. It is distinguished from giant cell tumor of bone by the clustered, focal arrangement of giant cells around hemorrhage, rather than a uniform distribution.

Question 6911

Topic: 10. Pathology and Oncology

Which of the following histological or molecular features best distinguishes a giant cell reparative granuloma (GCRG) of a metacarpal from a true giant cell tumor (GCT) of bone?

. Absence of an H3F3A mutation in GCRG
. A mononuclear cell background expressing intense RANKL in GCRG
. A uniform and diffuse distribution of multinucleated giant cells in GCRG
. Presence of prominent cartilaginous matrix in GCRG
. Severe nuclear atypia and high mitotic rate in GCRG

Correct Answer & Explanation

. Absence of an H3F3A mutation in GCRG

Explanation

Over 90% of true Giant Cell Tumors of bone harbor a mutation in the H3F3A gene, which is absent in Giant Cell Reparative Granulomas. Additionally, GCRG typically features clustered giant cells in a fibroblastic background, unlike the uniform distribution seen in GCT.

Question 6912

Topic: 10. Pathology and Oncology

A 22-year-old female presents with a lytic lesion in the proximal phalanx of her ring finger. Biopsy reveals multinucleated giant cells arranged irregularly around areas of prominent hemorrhage, separated by a spindle-cell fibrous stroma. Which of the following is the most likely diagnosis?

. Giant Cell Tumor of Bone
. Giant Cell Reparative Granuloma
. Aneurysmal Bone Cyst
. Enchondroma
. Chondroblastoma

Correct Answer & Explanation

. Giant Cell Reparative Granuloma

Explanation

Giant Cell Reparative Granuloma (GCRG) classically presents in the small bones of the hands/feet or the mandible. Histologically, it is distinguished from Giant Cell Tumor of Bone by the clustering of giant cells around hemorrhage and a fibrotic, spindle-cell stroma.

Question 6913

Topic: 10. Pathology and Oncology

A 35-year-old patient undergoes a biopsy of an expansile, lytic lesion in the third metacarpal. Pathology reports findings consistent with a Giant Cell Reparative Granuloma. What laboratory workup is mandatory to rule out a mimicking systemic condition?

. Serum protein electrophoresis
. Thyroid stimulating hormone
. Serum calcium, phosphorus, and intact parathyroid hormone (PTH)
. Rheumatoid factor and anti-CCP
. HLA-B27

Correct Answer & Explanation

. Serum calcium, phosphorus, and intact parathyroid hormone (PTH)

Explanation

The histologic appearance of a Giant Cell Reparative Granuloma is virtually identical to that of a Brown tumor seen in hyperparathyroidism. Therefore, it is mandatory to check serum calcium, phosphorus, and PTH to rule out primary or secondary hyperparathyroidism.

Question 6914

Topic: 10. Pathology and Oncology

A 22-year-old female presents with a lytic, expansile lesion in the first metatarsal. Biopsy shows a fibroblastic stroma with focal hemorrhage, hemosiderin deposition, and multinucleated giant cells clustered around the areas of hemorrhage. Serum calcium, phosphorus, and PTH are normal. Which of the following is true regarding this condition?

. It is histologically indistinguishable from a brown tumor of hyperparathyroidism.
. It typically involves the epiphysis of long bones.
. It is associated with a mutation in the H3F3A gene.
. Malignant transformation occurs in 10% of cases.
. It is characterized by giant cells uniformly distributed throughout the stroma.

Correct Answer & Explanation

. It is histologically indistinguishable from a brown tumor of hyperparathyroidism.

Explanation

Giant cell reparative granuloma (GCRG) is histologically identical to a brown tumor of hyperparathyroidism, making serum calcium and PTH testing mandatory to differentiate the two. Unlike giant cell tumor of bone (which has uniformly distributed giant cells and H3F3A mutations), GCRG features giant cells clustered around hemorrhage.

Question 6915

Topic: 10. Pathology and Oncology

A 30-year-old female experiences spontaneous resorption of her mandible over several years. Biopsy of the affected area is most likely to demonstrate which of the following?

. Atypical spindle cells producing osteoid matrix
. Mononuclear cells with grooved nuclei and eosinophils
. Benign proliferation of thin-walled vascular and lymphatic channels
. Granulomatous inflammation with caseating necrosis
. Woven bone trabeculae rimmed by prominent osteoblasts in a loose fibrous stroma

Correct Answer & Explanation

. Benign proliferation of thin-walled vascular and lymphatic channels

Explanation

Gorham's disease (massive osteolysis) is characterized by a benign, non-neoplastic proliferation of thin-walled vascular and lymphatic channels within bone. This proliferation leads to progressive osteolysis and the classic "disappearing bone" radiographic appearance.

Question 6916

Topic: 10. Pathology and Oncology

A 16-year-old boy has an expansile, osteolytic lesion in the distal phalanx of his thumb. Biopsy confirms a giant cell reparative granuloma. What is the most appropriate initial surgical management?

. Amputation of the thumb
. En bloc resection and structural allograft
. Intralesional curettage and bone grafting
. Wide local excision with margins
. Radiation therapy

Correct Answer & Explanation

. Intralesional curettage and bone grafting

Explanation

Giant cell reparative granuloma (GCRG) is a benign, reactive process. The standard of care is intralesional curettage, often followed by bone grafting or cementation, which provides excellent local control and preserves function.

Question 6917

Topic: 10. Pathology and Oncology

A 16-year-old female presents with an expansile, radiolucent lesion in her first metacarpal. Biopsy reveals a spindle cell stroma, reactive bone formation, and multinucleated giant cells clustered primarily around areas of hemorrhage. Serum calcium, phosphorus, and parathyroid hormone levels are normal. Which of the following is the most likely diagnosis?

. Giant cell tumor of bone
. Brown tumor of hyperparathyroidism
. Aneurysmal bone cyst
. Giant cell reparative granuloma
. Chondromyxoid fibroma

Correct Answer & Explanation

. Giant cell reparative granuloma

Explanation

Giant cell reparative granuloma (GCRG) typically occurs in the hands, feet, and jaw, presenting as an expansile lytic lesion. Histologically, it is distinguished from giant cell tumors by having giant cells clustered around hemorrhage and a prominent spindle cell stroma, with normal systemic endocrine labs.

Question 6918

Topic: 10. Pathology and Oncology

When distinguishing a Giant Cell Reparative Granuloma (GCRG) from a Giant Cell Tumor (GCT) of bone pathologically, which of the following histological features strongly favors a diagnosis of GCRG?

. Uniform distribution of giant cells throughout the stroma
. Mononuclear cells resembling the nuclei of the giant cells
. Presence of a sarcomatous spindle cell background
. Zonal clustering of giant cells around areas of hemorrhage and reactive bone
. Absence of fibroblastic tissue

Correct Answer & Explanation

. Zonal clustering of giant cells around areas of hemorrhage and reactive bone

Explanation

In GCRG, giant cells are typically clustered unevenly around areas of hemorrhage and reactive woven bone within a prominent spindle cell stroma. In contrast, GCT of bone features uniformly distributed giant cells among mononuclear cells with identical-appearing nuclei.

Question 6919

Topic: 10. Pathology and Oncology

A 75-year-old female with long-standing polyostotic Paget's disease presents with new, severe, unremitting thigh pain and localized swelling. Radiographs reveal a new destructive lytic lesion breaking through the cortex. What is the most likely diagnosis?

. Chondrosarcoma
. Ewing sarcoma
. Multiple myeloma
. Secondary osteosarcoma
. Metastatic breast carcinoma

Correct Answer & Explanation

. Secondary osteosarcoma

Explanation

Secondary osteosarcoma is the most common malignant transformation in Paget's disease, occurring in about 1% of patients. It typically presents as new, severe pain and a destructive lesion in an area of long-standing pagetic bone.

Question 6920

Topic: 10. Pathology and Oncology

A 72-year-old male with a long-standing history of symptomatic Paget's disease presents with a sudden onset of severe, unrelenting pain in his right femur. Radiographs show a destructive lytic lesion with cortical breakthrough. What is the most likely diagnosis?

. Secondary osteosarcoma
. Metastatic prostate cancer
. Pathologic insufficiency fracture
. Multiple myeloma
. Chondrosarcoma

Correct Answer & Explanation

. Secondary osteosarcoma

Explanation

Secondary osteosarcoma is the most common malignant transformation in Paget's disease, affecting approximately 1% of patients. It typically presents with new-onset, severe pain and a destructive lytic lesion.

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