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10. Pathology and Oncology MCQs

Practice Set 242 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 4821

Topic: 10. Pathology and Oncology

A 25-year-old male presents with a slowly growing, painless mass near the popliteal fossa. Radiographs show a soft tissue mass with stippled calcifications. MRI demonstrates a heterogeneous mass adjacent to, but distinct from, the knee joint capsule. Histology demonstrates a biphasic pattern of epithelial and spindle cells. What is the characteristic genetic translocation associated with this diagnosis?

. t(11;22) (EWS-FLI1)
. t(X;18) (SYT-SSX)
. t(12;16) (FUS-DDIT3)
. t(9;22) (EWS-CHN)
. t(2;13) (PAX3-FOXO1)

Correct Answer & Explanation

. t(X;18) (SYT-SSX)

Explanation

The scenario describes synovial sarcoma, which typically occurs in young adults (15-40 years) and presents as a slow-growing mass near a joint (most commonly the knee), though it rarely involves the synovium directly. Up to 30% show calcification on radiographs. The pathognomonic translocation is t(X;18)(p11;q11), leading to the SYT-SSX fusion gene.

Question 4822

Topic: 10. Pathology and Oncology

A 55-year-old male presents with severe mechanical pelvic pain. Pelvic radiographs and CT show a large, destructive lesion in the ilium with ring-and-arc calcifications and prominent cortical breakthrough. Core needle biopsy confirms a Grade 2 conventional chondrosarcoma. Which of the following is the most appropriate primary treatment modality?

. Intralesional curettage with phenol and cementation
. Neoadjuvant multi-agent chemotherapy followed by wide surgical excision
. Wide surgical excision alone
. Definitive radiation therapy
. Radiofrequency ablation

Correct Answer & Explanation

. Wide surgical excision alone

Explanation

Conventional chondrosarcoma (Grade 2 and 3) is historically known to be resistant to both chemotherapy and radiation therapy due to its poor vascularity, low fraction of dividing cells, and abundant cartilaginous matrix. The mainstay of treatment is wide surgical excision. Intralesional curettage is reserved for benign cartilaginous lesions (enchondromas) or select Grade 1 atypical cartilaginous tumors in the appendicular skeleton, not for Grade 2 pelvic lesions.

Question 4823

Topic: 10. Pathology and Oncology
A 16-year-old girl undergoes 10 weeks of neoadjuvant multi-agent chemotherapy for an Enneking Stage IIB conventional osteosarcoma of the distal femur. She subsequently undergoes a limb-salvage distal femoral replacement. Which of the following is the most significant independent prognostic factor for her long-term overall survival?
. The absolute size of the initial tumor on MRI
. Her age at the time of diagnosis
. The degree of tumor necrosis found in the resected specimen
. The distance of the final surgical margin from the tumor
. Serum alkaline phosphatase levels post-resection

Correct Answer & Explanation

. The degree of tumor necrosis found in the resected specimen

Explanation

In conventional high-grade osteosarcoma, the histologic response to neoadjuvant chemotherapy, determined by the percentage of tumor necrosis in the resected specimen, is the single most important prognostic factor for long-term overall survival. Greater than 90% necrosis (Huvos grade III or IV) is considered a 'good' response and correlates with significantly higher survival rates compared to a poor response (<90% necrosis).

Question 4824

Topic: 10. Pathology and Oncology

A 62-year-old male with a history of clear cell renal cell carcinoma presents with progressive right arm pain. Radiographs reveal a large, purely lytic, destructive lesion in the humeral diaphysis with a Mirels' score of 10, indicating impending pathologic fracture. Prophylactic surgical stabilization is planned. Which of the following preoperative interventions is most highly recommended to minimize intraoperative morbidity?

. Preoperative administration of intravenous bisphosphonates for 3 days
. Preoperative radiation therapy to the entire humerus
. Preoperative percutaneous transarterial embolization of the lesion
. Neoadjuvant chemotherapy with a tyrosine kinase inhibitor
. Administration of high-dose corticosteroids 24 hours prior to surgery

Correct Answer & Explanation

. Preoperative percutaneous transarterial embolization of the lesion

Explanation

Metastatic renal cell carcinoma and thyroid carcinoma lesions are notoriously hypervascular. Extensive, sometimes life-threatening intraoperative hemorrhage is a major risk during orthopedic stabilization of these lesions. Preoperative percutaneous transarterial embolization, ideally performed 24-48 hours prior to surgery, significantly reduces intraoperative blood loss and associated morbidity.

Question 4825

Topic: 10. Pathology and Oncology

A 42-year-old male is diagnosed with myxoid liposarcoma of the proximal thigh following a core needle biopsy. The cytogenetics report confirms a t(12;16) translocation. In addition to a standard chest CT for staging, which imaging modality is uniquely indicated for staging this specific histologic subtype of soft tissue sarcoma?

. Positron emission tomography (PET) scan of the brain
. MRI of the entire spine
. Ultrasound of the regional inguinal lymph nodes
. Technetium-99m bone scan
. CT angiography of the lower extremity

Correct Answer & Explanation

. MRI of the entire spine

Explanation

Myxoid liposarcoma (associated with the t(12;16) FUS-DDIT3 translocation) has a unique propensity to metastasize to extrapulmonary soft tissue and osseous sites, particularly the spine, before or even without lung involvement. Therefore, screening the whole spine (and often the pelvis/abdomen) with MRI is specifically recommended during staging for this subtype, unlike most other soft tissue sarcomas where chest CT is the primary staging tool.

Question 4826

Topic: 10. Pathology and Oncology

A 38-year-old male presents with chronic, mild right shoulder pain. Radiographs demonstrate a well-marginated lytic lesion within the epiphysis of the proximal humerus with subtle internal calcifications. Histology from a biopsy shows cells with abundant clear cytoplasm and distinct cell boundaries, dispersed among areas of hyaline cartilage, alongside occasional multinucleated giant cells. What is the most likely diagnosis?

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

Correct Answer & Explanation

. Clear cell chondrosarcoma

Explanation

The location (epiphyseal) and imaging can mimic chondroblastoma or Giant Cell Tumor. However, chondroblastoma typically occurs in skeletally immature patients (teens). Clear cell chondrosarcoma is a rare, low-grade malignant tumor that preferentially occurs in the epiphyses of long bones in adult males (3rd to 5th decades). Histology shows characteristic 'clear cells' with distinct margins and central nuclei interspersed with hyaline cartilage.

Question 4827

Topic: 10. Pathology and Oncology

A 24-year-old male presents with a long-standing anterior bowing deformity of the tibia and recent onset of dull pain. Radiographs show a well-defined, multilocular, eccentric, 'soap-bubble' osteolytic lesion in the anterior cortex of the tibial diaphysis. Biopsy reveals a biphasic tumor consisting of epithelial cells arranged in nests and a surrounding bland, spindle-cell fibrous stroma. What is the most appropriate management?

. Intralesional curettage with high-speed burring and cementation
. Wide extra-articular resection with negative margins
. Primary multi-agent chemotherapy
. Observation with serial radiographs
. Preoperative radiation therapy followed by marginal excision

Correct Answer & Explanation

. Wide extra-articular resection with negative margins

Explanation

The clinical presentation and biphasic histology (epithelial nests within a fibrous stroma) in the anterior tibial cortex are pathognomonic for adamantinoma. Adamantinoma is a low-grade, slow-growing malignant primary bone tumor. Unlike osteofibrous dysplasia (which occurs in younger children and can resemble it), adamantinoma has metastatic potential. Standard treatment is wide surgical resection; it is resistant to chemotherapy and radiation, and curettage has a very high recurrence rate.

Question 4828

Topic: 10. Pathology and Oncology

A 58-year-old male presents with a 6-month history of worsening constipation and perianal numbness. Digital rectal examination reveals a firm, palpable presacral mass. An MRI demonstrates a large, lobulated destructive mass involving the S2-S4 sacral segments with profound T2 hyperintensity. CT-guided core biopsy shows large cells with abundant vacuolated cytoplasm arranged in cords. Which immunohistochemical marker is highly sensitive and specific for confirming this tumor?

. S-100
. Cytokeratin
. Vimentin
. Brachyury
. CD99

Correct Answer & Explanation

. Brachyury

Explanation

The tumor described is a sacral chordoma, which arises from notochordal remnants. The classic histologic finding is the 'physaliferous cell' containing abundant vacuolated cytoplasm. Brachyury, a transcription factor vital in notochordal development, is a highly sensitive and specific nuclear immunohistochemical marker for chordoma, which helps distinguish it from chondrosarcoma and other sacral mimics.

Question 4829

Topic: 10. Pathology and Oncology

A 30-year-old female presents with a painless, hard mass on the posterior aspect of her distal thigh. Radiographs demonstrate a densely ossified mass attached to the posterior cortex of the distal femur by a broad base, with no medullary involvement seen on MRI. Biopsy shows well-formed woven bone trabeculae separated by a low-grade spindle cell stroma. Which genetic alteration is a hallmark of this condition?

. MDM2 amplification
. TP53 mutation
. t(11;22) translocation
. GNAS mutation
. EXT1 mutation

Correct Answer & Explanation

. MDM2 amplification

Explanation

The clinical and radiographic presentation describes a parosteal osteosarcoma, a low-grade surface osteosarcoma typically found on the posterior aspect of the distal femur. Histologically, it features well-formed woven bone and a bland fibroblastic stroma. The hallmark molecular finding is amplification of the MDM2 and CDK4 genes on chromosome 12q13-15.

Question 4830

Topic: 10. Pathology and Oncology

A 65-year-old female presents with a rapidly enlarging, painful mass in her right shoulder. She has a history of right breast cancer treated with lumpectomy and local adjuvant radiation therapy 12 years ago. Radiographs show an aggressive, moth-eaten lytic lesion destroying the body of the scapula with an associated large soft tissue mass. What is the most common histologic subtype of post-radiation primary bone sarcoma?

. Ewing sarcoma
. Chondrosarcoma
. Osteosarcoma
. Chordoma
. Angiosarcoma

Correct Answer & Explanation

. Osteosarcoma

Explanation

Radiation-induced sarcomas of bone are rare but devastating late complications of radiation therapy, typically occurring with a latency of 5 to 15 years (often much longer). They are virtually always high-grade. Osteosarcoma is the most common histologic type of secondary, radiation-induced bone sarcoma, followed closely by fibrosarcoma/undifferentiated pleomorphic sarcoma (UPS).

Question 4831

Topic: 10. Pathology and Oncology

A 22-year-old female presents with a painless, slow-growing, highly vascular mass in her left deep anterior thigh. Her primary complaint, however, is a recent onset of severe headaches and left-sided visual field deficits. A staging brain MRI confirms a hemorrhagic solitary metastasis in the right occipital lobe. What is the most likely soft tissue sarcoma diagnosis?

. Synovial sarcoma
. Alveolar soft part sarcoma
. Epithelioid sarcoma
. Clear cell sarcoma
. Pleomorphic liposarcoma

Correct Answer & Explanation

. Alveolar soft part sarcoma

Explanation

Alveolar soft part sarcoma (ASPS) is a rare, highly vascular, slow-growing tumor typically found in the deep tissues of the thigh in young adults. It is notorious for early, wide hematogenous dissemination, with a distinct propensity to metastasize to the brain (up to 30% of cases), which is highly unusual for other soft tissue sarcomas. It is associated with the t(X;17) ASPSCR1-TFE3 translocation.

Question 4832

Topic: Bone Tumors

A 9-year-old boy incidentally undergoes radiography for mild shoulder pain, revealing a centrally located, well-circumscribed, purely lytic lesion in the proximal humeral metaphysis. An MRI demonstrates a single fluid-filled cavity with no fluid-fluid levels. During a diagnostic aspiration, clear yellow fluid is obtained. Which of the following is true regarding the biochemical fluid contents of this specific lesion?

. It will demonstrate high levels of basic fibroblast growth factor (bFGF)
. It will have high concentrations of prostaglandins (PGE2) and interleukin-1 (IL-1)
. It will clot rapidly upon exposure to room air due to high fibrinogen
. It will be heavily nucleated with neoplastic spindle cells
. It will show an abundance of multinucleated giant cells on cytology

Correct Answer & Explanation

. It will have high concentrations of prostaglandins (PGE2) and interleukin-1 (IL-1)

Explanation

The lesion described is a Unicameral Bone Cyst (UBC), which typically yields clear, yellowish serous fluid upon aspiration. Analysis of UBC fluid demonstrates high levels of bone-resorbing factors, specifically prostaglandins (such as PGE2) and inflammatory cytokines like Interleukin-1 (IL-1), IL-6, and nitrogen oxides. This local biochemical environment promotes osteoclast activation and cyst expansion.

Question 4833

Topic: 10. Pathology and Oncology

A 26-year-old male presents with a firm, painless nodule on the volar aspect of his distal right forearm that has slowly enlarged over 2 years. He previously had similar nodules locally excised, which were misdiagnosed as deep necrotizing granulomas, but they rapidly recurred. Physical exam shows focal ulceration of the overlying skin. What is the most characteristic secondary mode of dissemination for this specific sarcoma subtype?

. Strictly transcoelomic spread
. High propensity for early regional lymph node metastasis
. Dissemination exclusively through the portal venous system
. Spread via the cerebrospinal fluid (CSF)
. Intra-articular seeding of the adjacent joint

Correct Answer & Explanation

. High propensity for early regional lymph node metastasis

Explanation

The clinical picture of a distal extremity nodule in a young adult that mimics a granuloma, ulcerates the skin, and spreads proximally is classic for epithelioid sarcoma. Notably, epithelioid sarcoma has a significantly higher rate of regional lymph node metastasis compared to most other soft tissue sarcomas (up to 30-40%), necessitating careful evaluation (often PET or sentinel node biopsy) of the draining lymph node basins.

Question 4834

Topic: Bone Tumors

A 19-year-old male presents with chronic, dull back pain that profoundly worsens at night. He notes that naproxen provides significant, albeit temporary, relief. CT scan reveals a 3.0 cm lytic defect in the posterior elements of L3, surrounded by extensive sclerosis. Histologically, the lesion consists of interconnecting woven bone trabeculae lined by prominent single layers of osteoblasts with a vascular stroma. Based on the overall presentation and imaging, what is the most likely diagnosis?

. Osteoid osteoma
. Osteoblastoma
. Aneurysmal bone cyst
. Giant cell tumor
. Chondromyxoid fibroma

Correct Answer & Explanation

. Osteoblastoma

Explanation

Osteoid osteoma and osteoblastoma share identical histologic features (woven bone trabeculae lined by prominent osteoblasts). They are differentiated primarily by size: osteoid osteomas are less than 1.5 - 2.0 cm in diameter, whereas osteoblastomas are larger (> 2.0 cm). Osteoblastomas also have a strong predilection for the posterior elements of the spine. While both can cause pain responsive to NSAIDs (due to prostaglandin production), the large size (3.0 cm) defines this as an osteoblastoma.

Question 4835

Topic: 10. Pathology and Oncology

According to the Musculoskeletal Tumor Society (MSTS) / Enneking staging system for benign bone tumors, an active benign tumor (Stage 2) is best described radiographically by which of the following findings?

. A well-defined lesion with a thick, sclerotic reactive rim and no cortical expansion
. A lesion with indistinct margins, cortical destruction, and an associated soft tissue mass
. A lesion with a thin, continuous reactive rim that causes mild expansion of the overlying cortex
. A highly permeative lesion with a 'sunburst' periosteal reaction
. A well-marginated lesion that has spontaneously healed and entirely ossified

Correct Answer & Explanation

. A lesion with a thin, continuous reactive rim that causes mild expansion of the overlying cortex

Explanation

In the Enneking staging system for benign tumors: Stage 1 (Latent) tumors are well-marginated with a thick sclerotic rim, showing no active growth (e.g., non-ossifying fibroma). Stage 2 (Active) tumors exhibit symptomatic growth, possess a thin but continuous reactive margin, and often expand the bone but remain contained within the periosteum (e.g., ABC, UBC). Stage 3 (Aggressive) tumors have indistinct margins, cortical breakthrough, and can form a soft tissue component (e.g., Giant Cell Tumor).

Question 4836

Topic: 10. Pathology and Oncology

A 45-year-old male presents with a suspected high-grade sarcoma in the distal thigh. A core needle biopsy is planned. Which of the following is an absolute requirement for the biopsy tract?

. It should be transverse to follow Langer lines.
. It must be excisable during the definitive tumor resection.
. It should cross multiple compartments to avoid contamination.
. It must be placed laterally to avoid the neurovascular bundle regardless of tumor location.
. It should utilize the standard surgical approach for a knee arthroplasty.

Correct Answer & Explanation

. It must be excisable during the definitive tumor resection.

Explanation

Biopsy tracts are considered contaminated and must be placed in a line that allows full excision en bloc with the tumor during definitive surgery. Longitudinal incisions are standard in the extremities to facilitate this.

Question 4837

Topic: 10. Pathology and Oncology

A 16-year-old girl is diagnosed with conventional osteosarcoma of the distal femur. Histology shows malignant spindle cells producing osteoid. Mutation in which of the following tumor suppressor genes is most strongly associated with her condition and a high risk of developing secondary malignancies like breast cancer?

. EXT1
. NF1
. TP53
. RB1
. GNAS

Correct Answer & Explanation

. TP53

Explanation

TP53 mutations are associated with Li-Fraumeni syndrome, which increases the risk for osteosarcoma, breast cancer, and other malignancies. RB1 mutations also predispose to osteosarcoma but are classically associated with retinoblastoma.

Question 4838

Topic: 10. Pathology and Oncology

A 40-year-old male presents with a painful lytic lesion in the proximal femoral epiphysis. Biopsy reveals cells with abundant clear cytoplasm, distinct borders, and scattered multinucleated giant cells. What is the most appropriate definitive treatment?

. Curettage and bone grafting
. Neoadjuvant chemotherapy followed by wide resection
. Wide surgical resection
. Radiation therapy
. Radiofrequency ablation

Correct Answer & Explanation

. Wide surgical resection

Explanation

The presentation and histology describe clear cell chondrosarcoma, a low-grade malignant tumor that uniquely affects the epiphysis. Treatment is wide surgical resection, as it is relatively resistant to chemotherapy and radiation.

Question 4839

Topic: 10. Pathology and Oncology

A 60-year-old male presents with an impending pathologic fracture of the proximal humerus secondary to metastatic renal cell carcinoma. Prophylactic stabilization is planned. Which of the following preoperative interventions is most critical to reduce perioperative morbidity?

. Preoperative systemic immunotherapy
. Preoperative radiation therapy
. Preoperative arterial embolization
. Administration of bisphosphonates 24 hours prior to surgery
. Initiation of denosumab therapy

Correct Answer & Explanation

. Preoperative arterial embolization

Explanation

Renal cell carcinoma and thyroid carcinoma metastases are notoriously hypervascular. Preoperative selective arterial embolization significantly decreases intraoperative blood loss and perioperative morbidity.

Question 4840

Topic: 10. Pathology and Oncology

A 55-year-old male presents with bowel and bladder dysfunction. Imaging reveals a large, destructive midline sacral mass. Histological examination shows cells with abundant bubbly cytoplasm arranged in cords. Immunohistochemistry will most likely be positive for which of the following markers?

. CD99
. Brachyury
. S100 only
. Desmin
. MDM2

Correct Answer & Explanation

. Brachyury

Explanation

The patient has a chordoma, characterized by physaliferous (bubbly) cells. Brachyury is a highly sensitive and specific immunohistochemical nuclear marker for chordoma, differentiating it from chondrosarcoma.

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