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10. Pathology and Oncology MCQs

Practice Set 92 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 1821

Topic: 10. Pathology and Oncology
  • A 60-year-old man with no history of cancer has a destructive lesion in the proximal femur. He has a long history of tobacco use, but stopped smoking 5 years ago. A needle biopsy specimen of the lesion shows adenocarcinoma. Which of the following studies will most likely pinpoint the source of the primary tumor?
. CT scan of the chest
. technetium bone scan
. bone marrow aspiration
. serum protein electrophoresis
. lateral skull radiograph

Correct Answer & Explanation

. CT scan of the chest

Explanation

Skeletal metastasis of unknown origin - ...plain radiographs of the chest established the diagnosis of carcinoma of the lung in seventeen patients (43%).......Unlike skeletal metastasis of known origin - most often breast or prostate - a metastasis of unknown origin usually originates in the lung or kidney. In the present series, the most common occult primary site was the lung (63%) and the second most common was the kidney (10%).

Question 1822

Topic: 10. Pathology and Oncology
The diagnostic distinction between a benign enchondroma and a low-grade intramedullary chondrosarcoma is based primarily on the
. clinical history and radiographic findings.
. technetium bone scan
. flow cytometry pattern of extracted chondrocytes
. immunohistochemical staining patterns of a biopsy specimen
. histologic features of a biopsy specimen stained with hematoxylin-eosin

Correct Answer & Explanation

. clinical history and radiographic findings.

Explanation

The diagnostic strategies for benign bone tumors center on the initial radiographic presentation. For example, a calcified, lytic phalangeal lesion strongly suggests the presence of cartilage that is consistent with enchondroma.

Question 1823

Topic: 10. Pathology and Oncology
An 8-year-old girl has had a painless enlarging mass of insidious onset in the left thigh for the past 3 weeks. Her mother denies any history of trauma, fever, or disease. Examination reveals a nontender, mobile mass in the left medial thigh. Her gait is normal. Biopsy results reveal a nonrhabdomyosarcoma soft-tissue sarcoma. The most appropriate treatment should consist of
. radiation therapy and chemotherapy.
. surgical drainage and antibiotics.
. surgical excision with chemotherapy and/or radiation therapy.
. proximal femoral resection, allograft prosthetic reconstruction, and chemotherapy.
. serial observation with repeat MRI in 3 months.

Correct Answer & Explanation

. surgical excision with chemotherapy and/or radiation therapy.

Explanation

In childhood, the more common soft-tissue sarcomas are rhabdomyosarcoma, synovial sarcoma, and fibrosarcoma. Rhabdomyosarcoma, treated with radiation therapy and chemotherapy, is a round cell tumor and is inconsistent with this patient’s histologic findings. Nonrhabdomyosarcoma childhood soft-tissue sarcomas are treated with surgical excision in conjunction with chemotherapy and/or radiation therapy. The histology reveals no inflammatory cells to suggest an abscess; therefore, antibiotics and drainage are unnecessary. The MRI scans clearly show a mass of soft tissue and no bone involvement; therefore, proximal femoral resection is not appropriate. Serial observation is not appropriate because of the history of enlargement and insidious onset.

Question 1824

Topic: 10. Pathology and Oncology
The radiographs reveal squamous cell carcinoma of the thumb involving the distal phalanx. Following biopsy confirmation, what would be the most appropriate course of management?
. Curettage and bone grafting
. External beam radiation
. Ray amputation of the thumb
. Interphalangeal (IP) joint disarticulation

Correct Answer & Explanation

. Interphalangeal (IP) joint disarticulation

Explanation

Squamous cell carcinoma of the fingertip/nail region is uncommon but remains the most common malignancy in the hand. A high degree of suspicion is needed to diagnose this condition. Biopsy and radiographs are necessary initially. The subsequent treatment depends on the extent of the lesion at the time of presentation. Treatment can vary from Mohs micrographic surgery (MMS) to digital amputation. Amputation is recommended when bone involvement is present. In this patient, because the distal phalanx tip is involved and no further bone involvement proximally was observed, an amputation at the IP joint level is recommended. More proximal involvement would require a more proximal amputation level. Curettage and bone graft is not appropriate for this malignant lesion. External beam radiation therapy is not a first-line treatment option for this condition. Metastatic spread is uncommon. MMS is inappropriate when bone invasion has occurred.

Question 1825

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

Correct Answer & Explanation

. amputation.

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 1826

Topic: 10. Pathology and Oncology

A 60-year-old man presents with progressive lower extremity weakness and hyperreflexia over the past 2 weeks. He has a history of renal cell carcinoma. MRI demonstrates a metastatic lesion in the T8 vertebral body causing high-grade epidural spinal cord compression (ESCC). He is ambulatory but requires assistance. According to the NOMS framework, what is the most appropriate management strategy?

. Conventional external beam radiation therapy (cEBRT) alone
. Stereotactic body radiation therapy (SBRT) alone
. Posterolateral decompression, separation surgery, followed by SBRT
. Anterior corpectomy and stabilization
. Systemic chemotherapy alone

Correct Answer & Explanation

. Conventional external beam radiation therapy (cEBRT) alone

Explanation

Renal cell carcinoma is a radioresistant tumor. The NOMS (Neurologic, Oncologic, Mechanical, Systemic) framework guides treatment. High-grade epidural spinal cord compression (ESCC grade 2 or 3) with a radioresistant tumor requires surgical decompression to create space between the tumor and spinal cord ('separation surgery') so that stereotactic body radiation therapy (SBRT) can be safely administered to the tumor without causing radiation myelopathy. cEBRT alone is ineffective for radioresistant tumors with high-grade compression.

Question 1827

Topic: 10. Pathology and Oncology

A 16-year-old boy presents with back pain that is worse at night and relieved by NSAIDs. Physical exam reveals a painful left-sided thoracic scoliosis. CT scan shows a 9 mm sclerotic lesion with a central lucent nidus in the left T8 pedicle. Which of the following is true regarding this condition?

. The lesion is typically found on the convex side of the scoliotic curve.
. Malignant transformation occurs in 5-10% of cases.
. Surgical excision or radiofrequency ablation of the nidus typically leads to resolution of the scoliosis if treated early.
. It is the most common malignant primary bone tumor of the spine in adolescents.
. Biopsy is required prior to definitive treatment due to its aggressive radiographic appearance.

Correct Answer & Explanation

. The lesion is typically found on the convex side of the scoliotic curve.

Explanation

Osteoid osteoma is a benign bone-forming tumor. In the spine, it most commonly affects the posterior elements (pedicle, pars, lamina) and causes a painful scoliosis. The tumor is typically located on the concave side of the scoliotic curve (muscle spasm on the side of the lesion causes the concavity). If the lesion is treated (via RFA or excision) within 15-18 months of symptom onset, the scoliosis usually resolves completely. If left longer, structural changes may occur, and the scoliosis may persist. It has no malignant potential.

Question 1828

Topic: 10. Pathology and Oncology

A 60-year-old man with known renal cell carcinoma presents with intractable mechanical back pain. Imaging reveals an L3 lytic metastasis with vertebral collapse, bilateral pedicle involvement, and no epidural spinal cord compression. The Spinal Instability Neoplastic Score (SINS) is 14. What is the most appropriate management?

. Conventional external beam radiation therapy alone
. Stereotactic body radiation therapy (SBRT) alone
. Surgical stabilization followed by radiation therapy
. Systemic chemotherapy alone
. Observation and bisphosphonates

Correct Answer & Explanation

. Conventional external beam radiation therapy alone

Explanation

A SINS score of 13 or greater indicates impending or actual spinal instability. Regardless of the tumor histology or presence of neurologic deficit, surgical stabilization is required prior to addressing the tumor with targeted radiation.

Question 1829

Topic: Bone Tumors

A 16-year-old boy presents with severe, progressive right-sided back pain that is worse at night and dramatically relieved by ibuprofen. Examination reveals a left-sided thoracic scoliosis. CT scan shows a 1 cm sclerotic lesion with a central lucent nidus in the right T8 pedicle. Which of the following best describes the relationship between the lesion and the scoliotic curve?

. The lesion is located on the convexity of the curve.
. The lesion is located on the concavity of the curve.
. The curve is structural and will not resolve after lesion excision.
. The lesion is located at the apex of a compensatory lumbar curve.
. The curve magnitude correlates inversely with the patient's age.

Correct Answer & Explanation

. The lesion is located on the convexity of the curve.

Explanation

In spinal osteoid osteoma, muscle spasms on the side of the lesion cause a secondary scoliosis. The lesion is characteristically located on the concave side of the scoliotic curve.

Question 1830

Topic: 10. Pathology and Oncology

A 62-year-old man presents with dull, aching sacral pain and recent onset of bowel/bladder dysfunction. MRI demonstrates a large, destructive midline sacral mass. Biopsy reveals physaliferous cells with abundant vacuolated cytoplasm. What is the most appropriate definitive management?

. Chemotherapy followed by radiation
. Intralesional curettage and cementing
. Wide en bloc surgical resection
. Primary radiation therapy alone
. Radiofrequency ablation

Correct Answer & Explanation

. Chemotherapy followed by radiation

Explanation

The diagnosis is a chordoma, characterized by physaliferous cells. Chordomas are locally aggressive and largely resistant to conventional chemotherapy and radiation. Wide en bloc resection offers the best chance for local control and long-term survival.

Question 1831

Topic: 10. Pathology and Oncology

A 55-year-old man with a history of renal cell carcinoma presents with progressive paraparesis. MRI shows a destructive lesion in the T8 vertebral body causing severe spinal cord compression. The tumor is highly vascular and radioresistant. Which of the following is the most appropriate surgical approach?

. Posterior laminectomy alone
. Preoperative embolization followed by anterior corpectomy and stabilization
. Fractionated external beam radiation alone
. Stereotactic radiosurgery alone
. Chemotherapy followed by kyphoplasty

Correct Answer & Explanation

. Posterior laminectomy alone

Explanation

Renal cell carcinoma spinal metastases are highly vascular and typically radioresistant. Preoperative embolization significantly reduces intraoperative blood loss prior to definitive anterior decompression (corpectomy) and stabilization.

Question 1832

Topic: 10. Pathology and Oncology
  • A 47-year-old woman who reports mild, aching pain in her knee has no history of trauma. Examination of the knee is normal. Figure 23a shows the AP radiograph. A bone scan shows increased uptake at this site only. Figure 23b shows the CT scan, and Figure 23c shows the histology from the CT scan-guided needle biopsy. Treatment should include
. extended curettage and polymethylmethacrylate cementation
. extra-articular resection of the knee and an allograft arthrodesis
. wide resection of the proximal tibia and custom prosthetic replacement
. prophylactic internal fixation and postoperative irradiation
. excision of the lateral condyle and reconstruction with a hemicondylar allograft

Correct Answer & Explanation

. extended curettage and polymethylmethacrylate cementation

Explanation

Patients with giant cell tumors typically present with local pain, swelling and tenderness. Radiographs usually reveal a lesion destructive of both medullary and cortical bone. The lesion is characterized by an expanding zone of radiolucency that is located eccentrically in the end of a long bone in an adult.The modern technique for the removal of a giant cell tumor involves wide decortication of all the bone overlying the area of the tumor. The cavity is filled with methylmethacrylate bone cement and covered with demineralized bone matrix to stimulate the restoration of strong corticalboundaries. The other procedures are much more invasive and not necessary to treat a low-grade neo-plastic lesion such as a giant cell tumor. Fewer complications and better functional results have been found after intralesional excision and insertion of methylmethacrylate than other techniques.

Question 1833

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.” 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.

Question 1834

Topic: 10. Pathology and Oncology
Which local treatment option is most appropriate?
. Radiation and wide surgical resection
. Extended curettage with adjuvants
. Wide surgical resection
. Revision knee arthroplasty

Correct Answer & Explanation

. Wide surgical resection

Explanation

This patient has a pathologic femur fracture. The histopathology reveals a cartilage tumor. The chondroid tissue appears to be low grade. However, in an adjacent region there is a high-grade component seen that does not resemble cartilage. This is highly suggestive of a dedifferentiated chondrosarcoma. This component signifies that a portion of the original tumor (low-grade chondrosarcoma) converted into a different cell lineage with more aggressive properties. Dedifferentiated chondrosarcoma is a highly aggressive malignancy. Wide resection is the local treatment of choice for high-grade chondrosarcoma; because of the fracture, this patient may require an amputation to achieve wide margins.

Question 1835

Topic: 10. Pathology and Oncology
A 33-year-old woman reports a mass on the right hand that has been enlarging for 1 year. An intraoperative photograph is shown in Figure 28a, and a biopsy specimen is shown in Figure 28b. What is the most likely diagnosis?
. Ganglion cyst
. Abscess
. Hematoma
. Giant cell tumor of tendon sheath
. Synovial sarcoma

Correct Answer & Explanation

. Giant cell tumor of tendon sheath

Explanation

Giant cell tumor of the tendon sheath is the most common solid soft-tissue mass in the hand. These tumors are slow-growing and may be present for months or years before coming to medical attention. The gross appearance is that of a lobulated mass that may be multicolored; typically yellow, brown, red, and gray. Histologically the lesion consists of multinucleated giant cells, polygonal mononuclear cells, and histiocytes that may contain abundant hemosiderin or lipid.

Question 1836

Topic: 10. Pathology and Oncology
The underlying cause of the neoplasm is
. ALK gene rearrangement.
. a nongerm-cell mutation of the GNAS1 gene.
. a germline alteration in EXT1 and EXT2.
. an abnormality arising from the translocation t(11;14)(q13;q32).

Correct Answer & Explanation

. a nongerm-cell mutation of the GNAS1 gene.

Explanation

The bone scan reveals multiple bone lesions, which does not rule out any of the responses. The radiographs reveal dysplastic bone with a “ground glass” appearance, suggesting fibrous dysplasia as the preferred response. Multiple myeloma typically demonstrates purely lytic, “punched out” lesions and would be highly unusual in a 23-year-old woman. Multiple hereditary exostosis would demonstrate more expansile lesions concentrated in the metaphysis. Metastatic carcinoma could have a lytic or blastic appearance but is less likely to occur in a 23-year-old woman. McCune-Albright syndrome in polyostotic fibrous dysplasia is present in as many as 50% of patients and should be evaluated for during an endocrine consultation. Adrenal, pituitary, parathyroid, and thyroid endocrinopathies may be present. Untreated hyperthyroidism can be life-threatening during a surgical procedure. There is no indication to repeat the nuclear bone scan. Although phosphate wasting and, rarely, oncogenic osteomalacia have been reported in polyostotic fibrous dysplasia, an endocrinology consultation always should be sought. Café au lait macules are the most common extraskeletal manifestation of fibrous dysplasia, often referred to as “coast of Maine” in appearance because of their irregular borders (in comparison to the “Coast of California” with smooth borders as seen in neurofibromatosis). Multiple myeloma would not ordinarily appear with increased uptake on a bone scan unless a pathologic fracture of some duration were present. A long area of bone involvement would not appear in patients with metastatic lung adenocarcinoma. An ALK rearrangement occurs in non-small-cell lung cancer. The translocation t(11;14)(q13;q32) should be recognized as a poor prognosticator in multiple myeloma. The germline alteration in EXT1 and EXT2 occurs in multiple hereditary exostosis. All forms of fibrous dysplasia are caused by a nongerm-cell mutation that occurs during early embryogenesis. A missense mutation of the GNAS1 gene, which encodes the alpha subunit of the stimulatory G-protein-coupled receptor, Gs alpha, results in G-protein activation and the production of cyclic adenosine monophosphate affecting melanocytes, endocrine cells, and osteoprogenitor cells.

Question 1837

Topic: Bone Tumors
What process is often found associated with other neoplasms?
. Osteomyelitis
. Osteoblastoma
. Aneurysmal bone cyst
. Giant cell tumor
. Eosinophilic granuloma

Correct Answer & Explanation

. Aneurysmal bone cyst

Explanation

Aneurysmal bone cyst may be either a “pattern” or a “diagnosis.” Therefore, aneurysmal bone cyst should be viewed as a diagnosis of exclusion. Hemorrhage into a variety of primary bone lesions (e.g., giant cell tumor of bone, chondroblastoma, osteoblastoma, fibrous dysplasia, osteosarcoma, or vascular neoplasms) may result in intralesional, membrane-bone blood-filled cysts. Such secondary changes may be confused with aneurysmal bone cyst, resulting in inappropriate therapy because assessment should be focused on identifying the underlying primary process. The entire specimen should be examined histologically in an effort to locate an underlying primary bone tumor.

Question 1838

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.

Question 1839

Topic: 10. Pathology and Oncology
A 69-year-old woman reports a painful clicking in her right shoulder. A soft-tissue mass is palpated at the lower portion of the scapula. Based on the MRI scan and biopsy specimens, what is the most likely diagnosis?
. Elastofibroma
. Lymphoma
. Malignant fibrous histiocytoma
. Synovial sarcoma
. Fibromatosis

Correct Answer & Explanation

. Elastofibroma

Explanation

Elastofibroma is a rare, benign soft-tissue pseudotumor characteristically located in the subscapular region. Most patients are between 50 and 70 years of age and have pain, decreased shoulder range of motion, or a mass. The lesion usually is best visualized with the arm elevated forward and adducted to displace the scapula laterally and allow the mass to protrude from the chest wall. They are frequently bilateral. Grossly, the mass is ill-defined, oblong or spherical, firm, and ranges in size from 5 cm to 10 cm. These masses appear infiltrative and frequently are mistaken for a sarcomatous lesion. Histologically, the mass is composed of a mixture of intertwining eosinophilic collagen and elastic fibers, and scattered fibroblasts, mucoid material, and fat.

Question 1840

Topic: 10. Pathology and Oncology
What is the most common presentation of a benign bone tumor in childhood?
. Pain
. Deformity
. Pathologic fracture
. Presence of a mass
. Incidental finding

Correct Answer & Explanation

. Incidental finding

Explanation

The most common benign bone tumors in childhood are discovered incidentally and include single bone cysts, fibrous cortical defects, nonossifying fibroma, and osteochondroma. Benign bone tumors can be classified as latent, active, or aggressive. Aggressive bone tumors usually present with pain, whereas active lesions present with pain or pathologic fracture. Only aggressive benign bone tumors are associated with a soft-tissue mass, and they are far less common than indolent bone tumors, especially in children.

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