Menu

10. Pathology and Oncology MCQs

Practice Set 239 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 4761

Topic: 10. Pathology and Oncology

A resident is performing an open incisional biopsy of a suspected high-grade soft tissue sarcoma located in the vastus lateralis muscle of the thigh. Which of the following technical principles is mandatory to prevent compromising future definitive limb-salvage surgery?

. Ensure meticulous hemostasis to prevent a post-biopsy hematoma that extends beyond the anatomical compartment
. Use a transverse skin incision to parallel Langer's lines and optimize wound healing
. Expose the adjacent neurovascular bundle to confirm it is not involved by the tumor
. Raise wide subfascial skin flaps to fully visualize the extent of the soft tissue mass
. Sample the necrotic center of the tumor to assure the highest yield of frankly malignant cells

Correct Answer & Explanation

. Ensure meticulous hemostasis to prevent a post-biopsy hematoma that extends beyond the anatomical compartment

Explanation

During biopsy of a suspected sarcoma, strict compartmentalization rules apply. Meticulous hemostasis is mandatory to prevent a hematoma from tracking tumor cells into adjacent pristine compartments. Incisions must be longitudinal (so the tract can be excised en bloc). Flaps should not be raised. Neurovascular bundles must not be unnecessarily exposed (risks contamination). The viable periphery, not the necrotic center, should be biopsied.

Question 4762

Topic: 10. Pathology and Oncology

A 16-year-old female presents with a rapidly enlarging, painful mass in her distal femur. Imaging shows an expansile, eccentric metaphyseal lytic lesion. MRI reveals multiple fluid-fluid levels. Biopsy shows blood-filled cavernous spaces lacking an endothelial lining, surrounded by spindle cells and multinucleated giant cells. Recent molecular studies demonstrate that the primary form of this lesion is frequently driven by a genetic translocation involving which gene?

. RUNX2
. USP6
. GNAS
. MDM2
. SYT-SSX

Correct Answer & Explanation

. USP6

Explanation

The lesion is an Aneurysmal Bone Cyst (ABC). Primary ABCs are now known to be true neoplasms driven by specific translocations, most commonly t(16;17), which results in the upregulation of the USP6 gene (ubiquitin-specific protease 6). Secondary ABCs (arising in GCT, chondroblastoma, etc.) lack this USP6 translocation.

Question 4763

Topic: 10. Pathology and Oncology

A 35-year-old male presents with a slow-growing, indolent 'bubbly' lytic lesion in the anterior diaphysis of the tibia. Biopsy reveals a biphasic tumor consisting of nests of epithelial cells within a benign-appearing fibrous stroma. Immunohistochemistry is strongly positive for cytokeratin. Due to its biological behavior, what is the standard surgical treatment for this primary lesion?

. Intralesional curettage with high-speed burring and phenol adjuvant
. Wide en bloc resection
. Marginal excision preserving the periosteum
. Primary radiation therapy with bisphosphonates
. Immediate above-knee amputation

Correct Answer & Explanation

. Wide en bloc resection

Explanation

The diagnosis is Adamantinoma, a low-grade malignant bone tumor predominantly occurring in the anterior tibial diaphysis. Histology shows a biphasic pattern (epithelial and fibrous elements), and the epithelial cells are cytokeratin positive. Because it is a malignant tumor with the potential to metastasize (most commonly to the lungs), the standard of care is wide en bloc resection, usually followed by intercalary reconstruction. Curettage leads to unacceptable recurrence rates.

Question 4764

Topic: Bone Tumors

A 45-year-old female with known polyostotic fibrous dysplasia presents with a newly noticed, painless soft tissue mass in her right anterior thigh. MRI shows a well-circumscribed, T2-hyperintense intramuscular lesion. Biopsy reveals hypocellular, abundant myxoid stroma with rare bland spindle cells and no lipoblasts. The combination of these findings characterizes which of the following syndromes?

. Mazabraud syndrome
. McCune-Albright syndrome
. Maffucci syndrome
. Ollier disease
. Gardner syndrome

Correct Answer & Explanation

. Mazabraud syndrome

Explanation

Mazabraud syndrome is the rare association of single or multiple intramuscular myxomas (the soft tissue mass described) with fibrous dysplasia (which may be monostotic or polyostotic). McCune-Albright syndrome features fibrous dysplasia, precocious puberty, and cafe-au-lait spots. Maffucci syndrome involves multiple enchondromas and soft tissue hemangiomas.

Question 4765

Topic: 10. Pathology and Oncology

A 28-year-old female is evaluated for a new onset seizure. Workup reveals a solitary brain metastasis. Thorough systemic staging uncovers a slow-growing, highly vascular soft tissue mass deep in her right thigh. Biopsy of the thigh mass reveals large, uniform, polygonal cells arranged in discrete nests separated by delicate sinusoidal vascular channels. A genetic translocation resulting in an ASPSCR1-TFE3 fusion is detected. Which sarcoma is this?

. Synovial sarcoma
. Clear cell sarcoma
. Alveolar soft part sarcoma
. Epithelioid sarcoma
. Undifferentiated pleomorphic sarcoma

Correct Answer & Explanation

. Alveolar soft part sarcoma

Explanation

Alveolar soft part sarcoma (ASPS) is a rare soft tissue sarcoma typically affecting young adults. It is notorious for early hematogenous metastasis, particularly to the brain and lungs, often before the primary tumor is detected. Histologically, it features large polygonal cells in a pseudoalveolar (nesting) pattern. It is characterized by the t(X;17)(p11;q25) translocation, yielding the ASPSCR1-TFE3 fusion.

Question 4766

Topic: 10. Pathology and Oncology

A 30-year-old female presents with a firm mass on the posterior aspect of her distal thigh. Radiographs demonstrate a dense, heavily ossified mass arising from the surface of the posterior distal femur. There is a broad base of attachment to the cortex, and cross-sectional imaging confirms no medullary continuity. Histology shows low-grade, well-differentiated bone and fibrous tissue. Which of the following molecular alterations is classically associated with this specific tumor?

. MDM2 and CDK4 amplification
. EXT1 mutation
. GNAS mutation
. USP6 translocation
. H3F3A mutation

Correct Answer & Explanation

. MDM2 and CDK4 amplification

Explanation

The clinical and radiographic presentation describes a parosteal osteosarcoma (surface osteosarcoma, typically low-grade, arising posterior distal femur, lacking medullary continuity unlike an osteochondroma). Parosteal osteosarcomas, like atypical lipomatous tumors/well-differentiated liposarcomas, are characterized by supernumerary ring chromosomes containing amplifications of the 12q13-15 region, which includes the MDM2 and CDK4 genes. EXT1 is for osteochondromas, GNAS for fibrous dysplasia, USP6 for ABC, H3F3A for giant cell tumor of bone.

Question 4767

Topic: 10. Pathology and Oncology

A patient with Ewing sarcoma undergoes systemic staging. Which of the following represents the most significant adverse prognostic factor for overall survival in this patient?

. Age greater than 10 years at presentation
. Tumor volume greater than 200 mL
. Presence of bone marrow or distant bone metastases
. Pelvic primary tumor location
. Poor histologic response to neoadjuvant chemotherapy

Correct Answer & Explanation

. Presence of bone marrow or distant bone metastases

Explanation

While large tumor volume (>200 mL), pelvic location, and poor response to chemotherapy are all well-established poor prognostic factors in Ewing sarcoma, the single most significant adverse prognostic factor is the presence of distant metastases at presentation, specifically bone or bone marrow metastases (which carry a worse prognosis than isolated pulmonary metastases). Overall survival drops to <30% in these patients.

Question 4768

Topic: 10. Pathology and Oncology

A 28-year-old male presents with a slowly enlarging, painless mass near his knee joint. Radiographs reveal a soft tissue mass with stippled calcifications. Biopsy demonstrates a biphasic tumor with both epithelial and spindle cell components. Which of the following genetic translocations is most characteristic of this lesion?

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

Correct Answer & Explanation

. t(X;18)

Explanation

Synovial sarcoma is characterized by the t(X;18)(p11;q11) translocation, resulting in the SYT-SSX fusion gene. It commonly presents in young adults near joints (though rarely intra-articular) and shows stippled calcifications on radiographs in about 30% of cases.

Question 4769

Topic: Bone Tumors

A 40-year-old male presents with shoulder pain. Radiographs show a lytic lesion in the proximal humeral epiphysis with central calcifications. Histological examination reveals tumor cells with abundant clear cytoplasm, distinct cell membranes, and scattered areas of conventional chondrosarcoma. What is the most likely diagnosis?

. Chondroblastoma
. Clear cell chondrosarcoma
. Giant cell tumor of bone
. Aneurysmal bone cyst
. Osteosarcoma

Correct Answer & Explanation

. Clear cell chondrosarcoma

Explanation

Clear cell chondrosarcoma typically occurs in the epiphysis of long bones in adults (often older than those with chondroblastoma, which is also epiphyseal). Histology shows sheets of clear cells and may have areas of conventional low-grade chondrosarcoma.

Question 4770

Topic: 10. Pathology and Oncology

A 65-year-old female presents with a new onset of severe thigh pain. Radiographs show a longstanding calcified lesion in the medullary canal of the femur with a new, aggressive, lytic area destroying the cortex. Biopsy reveals a bimorphic pattern with a low-grade cartilaginous tumor abruptly transitioning to a high-grade spindle cell sarcoma. Which of the following best describes the prognosis and treatment?

. Excellent prognosis with curettage and bone grafting
. Requires wide resection but is insensitive to chemotherapy; poor prognosis
. Treated primarily with radiation therapy; good prognosis
. Highly responsive to neoadjuvant chemotherapy; excellent prognosis
. Treated with wide resection and often systemic chemotherapy; extremely poor prognosis

Correct Answer & Explanation

. Treated with wide resection and often systemic chemotherapy; extremely poor prognosis

Explanation

Dedifferentiated chondrosarcoma features a low-grade cartilaginous tumor abruptly transitioning into a high-grade non-cartilaginous sarcoma. It is highly aggressive with a very poor prognosis. Treatment typically involves wide surgical resection and chemotherapy (similar to osteosarcoma protocols), though long-term survival remains low.

Question 4771

Topic: 10. Pathology and Oncology

Which of the following soft tissue sarcomas is most strongly associated with the t(2;13)(q35;q14) translocation, resulting in the PAX3-FOXO1 fusion protein, and often presents in the deep soft tissues of the extremities in adolescents?

. Embryonal rhabdomyosarcoma
. Alveolar rhabdomyosarcoma
. Pleomorphic rhabdomyosarcoma
. Epithelioid sarcoma
. Clear cell sarcoma

Correct Answer & Explanation

. Alveolar rhabdomyosarcoma

Explanation

Alveolar rhabdomyosarcoma typically presents in adolescents and young adults, often in the extremities, and is driven by the t(2;13) or t(1;13) translocation involving PAX3 or PAX7 and FOXO1. Embryonal RMS is more common in younger children and lacks this specific translocation.

Question 4772

Topic: 10. Pathology and Oncology

A 35-year-old male presents with an indolent swelling over the anterior aspect of his middle tibia. Imaging reveals a multilocular, diaphyseal eccentric osteolytic lesion with a 'soap-bubble' appearance. Immunohistochemistry of the biopsy specimen is strongly positive for cytokeratins. What is the most appropriate definitive management?

. Intralesional curettage and cementation
. Wide surgical resection
. Primary radiation therapy
. Neoadjuvant chemotherapy followed by curettage
. Radiofrequency ablation

Correct Answer & Explanation

. Wide surgical resection

Explanation

Adamantinoma is a rare, low-grade malignant bone tumor predominantly found in the anterior tibial diaphysis. It features an epithelial component (cytokeratin positive). Due to its risk of local recurrence and potential for metastasis, the treatment of choice is wide surgical resection. It does not respond well to chemotherapy or radiation.

Question 4773

Topic: 10. Pathology and Oncology

Epithelioid hemangioendothelioma (EHE) of bone is a rare vascular tumor. Which of the following statements regarding the behavior and presentation of EHE in bone is most accurate?

. It almost exclusively presents as a solitary lesion in the axial skeleton.
. Multifocal disease within a single anatomic region or limb is a characteristic presentation.
. It is a benign, self-limiting condition that spontaneously regresses.
. It is characterized by the t(11;22) EWSR1-FLI1 translocation.
. Surgical margin status has no impact on local recurrence rates.

Correct Answer & Explanation

. Multifocal disease within a single anatomic region or limb is a characteristic presentation.

Explanation

Vascular tumors of bone, including epithelioid hemangioendothelioma and hemangioma, uniquely have a tendency to be multifocal within the same anatomic region or a single limb (regional multicentricity). EHE is driven by a WWTR1-CAMTA1 fusion, not EWSR1-FLI1.

Question 4774

Topic: Bone Tumors

In a patient diagnosed with multiple myeloma, which of the following laboratory markers is considered the most powerful independent prognostic indicator of survival and is incorporated into the International Staging System (ISS)?

. Serum calcium level
. Bence Jones proteinuria
. Serum beta-2 microglobulin
. Alkaline phosphatase
. C-reactive protein

Correct Answer & Explanation

. Serum beta-2 microglobulin

Explanation

Serum beta-2 microglobulin (along with serum albumin) forms the basis of the International Staging System (ISS) for multiple myeloma and is the most significant prognostic factor. Higher levels correlate with higher tumor burden and a poorer prognosis.

Question 4775

Topic: 10. Pathology and Oncology

A 62-year-old female presents with a destructive lytic lesion in the proximal femur with an impending pathologic fracture. Biopsy confirms metastatic disease. Preoperative angiography and embolization are highly recommended prior to prophylactic stabilization for metastases originating from which of the following primary sources?

. Breast and Prostate
. Lung and Colon
. Renal and Thyroid
. Melanoma and Ovarian
. Gastric and Pancreatic

Correct Answer & Explanation

. Renal and Thyroid

Explanation

Metastases from renal cell carcinoma and thyroid carcinoma are notoriously hypervascular. Preoperative selective arterial embolization is strongly recommended to reduce intraoperative blood loss during surgical stabilization or resection.

Question 4776

Topic: 10. Pathology and Oncology

According to Cahan's criteria for the diagnosis of a post-radiation sarcoma, which of the following conditions must be met?

. The sarcoma must arise strictly within 1 year of radiation exposure.
. The new sarcoma must be of the exact same histological type as the original irradiated tumor.
. The sarcoma must arise within the previously irradiated field.
. The radiation dose must have exceeded 100 Gy.
. The patient must carry a germline TP53 mutation.

Correct Answer & Explanation

. The sarcoma must arise within the previously irradiated field.

Explanation

Cahan's criteria for post-radiation sarcoma include: 1) The new tumor must arise within the boundaries of the previous radiation field. 2) A latent period must exist (typically >4-5 years). 3) The new tumor must be histologically distinct from the original treated lesion. 4) There must be histological confirmation of the new sarcoma.

Question 4777

Topic: 10. Pathology and Oncology

Pigmented villonodular synovitis (PVNS), also known as tenosynovial giant cell tumor (TGCT), is driven by an overexpression of which of the following factors, providing a target for specific medical therapies such as pexidartinib?

. Vascular Endothelial Growth Factor (VEGF)
. Colony-Stimulating Factor 1 (CSF1)
. Fibroblast Growth Factor Receptor (FGFR)
. Epidermal Growth Factor Receptor (EGFR)
. Platelet-Derived Growth Factor (PDGF)

Correct Answer & Explanation

. Colony-Stimulating Factor 1 (CSF1)

Explanation

PVNS/TGCT is characterized by a specific chromosomal translocation t(1;2) that results in the overexpression of Colony-Stimulating Factor 1 (CSF1). This attracts macrophages that form the bulk of the tumor mass. Pexidartinib is a CSF1 receptor inhibitor approved for advanced or inoperable cases.

Question 4778

Topic: 10. Pathology and Oncology

A 25-year-old female presents with an expansile, purely lytic lesion in the mandible. Biopsy reveals spindle cells producing abundant collagen without nuclear atypia, mitosis, or necrosis. The lesion is considered the bony counterpart to aggressive fibromatosis (desmoid tumor). Which genetic pathway is most commonly implicated in the pathogenesis of this tumor?

. p53 tumor suppressor pathway
. Wnt/Beta-catenin pathway
. Hedgehog signaling pathway
. Notch signaling pathway
. MAPK/ERK pathway

Correct Answer & Explanation

. Wnt/Beta-catenin pathway

Explanation

Desmoplastic fibroma is the rare osseous counterpart of soft tissue aggressive fibromatosis (desmoid tumors). These tumors are frequently driven by mutations in the Wnt/beta-catenin pathway (e.g., CTNNB1 or APC mutations), leading to nuclear accumulation of beta-catenin.

Question 4779

Topic: Bone Tumors

A 9-year-old boy is scheduled to undergo a Van Nes rotationplasty for an osteosarcoma of the distal femur. For this procedure to be mechanically successful and functional, which of the following anatomical structures must be preserved and fully functional?

. Femoral artery
. Saphenous nerve
. Sciatic nerve
. Quadriceps mechanism
. Hamstrings

Correct Answer & Explanation

. Sciatic nerve

Explanation

In a Van Nes rotationplasty, the limb is shortened, rotated 180 degrees, and reattached so that the ankle joint functions as a knee joint. The sciatic nerve MUST be preserved to maintain motor and sensory function to the rotated leg and foot, which will now act as the calf and knee. The femoral vessels are often resected and anastomosed.

Question 4780

Topic: 10. Pathology and Oncology

According to the Enneking surgical margin classification system for musculoskeletal tumors, which of the following best defines a 'radical' margin?

. The resection plane passes directly through the tumor tissue.
. The resection plane passes through the reactive zone or pseudocapsule.
. The resection plane passes through normal healthy tissue, outside the reactive zone, but within the anatomical compartment.
. The entire anatomical compartment containing the tumor is removed from origin to insertion.
. The tumor is removed entirely via amputation regardless of the compartment.

Correct Answer & Explanation

. The resection plane passes through normal healthy tissue, outside the reactive zone, but within the anatomical compartment.

Explanation

In the Enneking system: Intralesional = through tumor; Marginal = through reactive zone/pseudocapsule; Wide = through normal tissue but within the involved compartment; Radical = removal of the entire anatomical compartment containing the tumor, extending from origin to insertion of the involved muscles/bones.

Test Yourself

Switch to an interactive, timed exam simulation to truly master this topic.

On this Page