Menu

10. Pathology and Oncology MCQs

Practice Set 312 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 6221

Topic: 10. Pathology and Oncology

A 29-year-old postpartum female presents with a firm, painless mass in her anterior abdominal wall. Biopsy reveals a bland fibroblastic proliferation lacking cytologic atypia, with strong nuclear beta-catenin staining. According to current consensus guidelines, what is the most appropriate initial management?

. Immediate wide local excision with 2 cm margins
. Amputation of the involved region
. Active surveillance (wait-and-see approach)
. High-dose local radiotherapy
. Systemic doxorubicin-based chemotherapy

Correct Answer & Explanation

. Active surveillance (wait-and-see approach)

Explanation

Desmoid tumors (aggressive fibromatoses) are locally aggressive but do not metastasize and are associated with beta-catenin mutations. Current consensus favors an initial "wait-and-see" approach (active surveillance), as many tumors remain stable or even spontaneously regress.

Question 6222

Topic: 10. Pathology and Oncology

A 35-year-old male presents with a slow-growing, painful mass on the plantar aspect of his foot. Radiographs demonstrate small stippled calcifications within the soft tissues. A core needle biopsy reveals a biphasic pattern of spindle cells and epithelial cells. Cytogenetic analysis of this tumor is most likely to demonstrate which of the following translocations?

. t(X;18)(p11;q11)
. t(12;16)(q13;p11)
. t(11;22)(q24;q12)
. t(2;13)(q35;q14)
. t(12;22)(q13;q12)

Correct Answer & Explanation

. t(X;18)(p11;q11)

Explanation

This is a synovial sarcoma, which frequently presents in the foot/ankle of young adults and may show calcifications on radiographs. It is characterized by the t(X;18) translocation resulting in the SYT-SSX fusion gene.

Question 6223

Topic: 10. Pathology and Oncology

A 45-year-old female presents with a deep intramuscular mass in her anterior thigh. Biopsy confirms the diagnosis of myxoid liposarcoma. Due to the unique metastatic behavior of this specific histologic subtype, which of the following additional imaging modalities is mandatory for accurate staging?

. Brain MRI
. Whole spine MRI
. Technetium-99m bone scan
. Sentinel lymph node biopsy
. Positron emission tomography (PET) scan

Correct Answer & Explanation

. Whole spine MRI

Explanation

Myxoid liposarcoma has a high propensity for extrapulmonary metastases, particularly to the bone and specifically the spine. Therefore, a whole spine MRI is uniquely recommended for staging this sarcoma.

Question 6224

Topic: 10. Pathology and Oncology



A 40-year-old male presents with chronic knee pain and locking. Imaging demonstrates multiple intra-articular radiopaque bodies. During arthroscopy, numerous cartilaginous nodules are found attached to the synovium. Which of the following best describes the underlying cellular process of this condition?

. Benign synovial hyperplasia with secondary hemosiderin deposition
. Metaplasia of the synovial intimal cells into chondrocytes
. Malignant proliferation of native chondroblasts
. Deposition of calcium pyrophosphate dihydrate crystals
. Neoplastic proliferation of synovial fibroblasts

Correct Answer & Explanation

. Metaplasia of the synovial intimal cells into chondrocytes

Explanation

Primary synovial chondromatosis is caused by the benign cartilaginous metaplasia of synovial intimal cells. These metaplastic nodules can detach and calcify or ossify within the joint space.

Question 6225

Topic: 10. Pathology and Oncology

A 30-year-old female presents with a deep 3 cm mass in her plantar aponeurosis. Biopsy reveals nests of pale cells with distinct nucleoli. Immunohistochemistry is strongly positive for S-100, HMB-45, and Melan-A. Given the diagnosis, staging should highly consider the risk of metastasis to which of the following sites?

. Bone marrow
. Brain parenchyma
. Regional lymph nodes
. Liver
. Spleen

Correct Answer & Explanation

. Regional lymph nodes

Explanation

The diagnosis is clear cell sarcoma (melanoma of soft parts), characterized by the t(12;22) translocation and positive melanoma markers (S-100, HMB-45). Like epithelioid and synovial sarcomas, it has a high rate of regional lymph node metastasis.

Question 6226

Topic: 10. Pathology and Oncology

A 65-year-old male presents with a large, deep painless mass in his posterior thigh. Core needle biopsy confirms a well-differentiated liposarcoma. Molecular cytogenetic testing of the tumor cells is most likely to reveal amplification of which of the following?

. SYT and SSX
. FUS and DDIT3
. MDM2 and CDK4
. COL1A1 and PDGFB
. ETV6 and NTRK3

Correct Answer & Explanation

. MDM2 and CDK4

Explanation

Well-differentiated and dedifferentiated liposarcomas are characterized by supernumerary ring chromosomes that lead to the amplification of MDM2 and CDK4 genes. This helps differentiate them from benign lipomas.

Question 6227

Topic: 10. Pathology and Oncology

A 28-year-old postpartum female complains of a firm, non-tender abdominal wall mass. Core biopsy reveals uniform, elongated spindle cells in a dense collagenous stroma without nuclear atypia. Immunohistochemistry shows nuclear staining for beta-catenin. What is the most widely accepted initial management for this lesion?

. Wide local excision with negative margins
. Neoadjuvant radiation therapy
. Active observation with serial imaging
. Cytotoxic multidrug chemotherapy
. Radiofrequency ablation

Correct Answer & Explanation

. Active observation with serial imaging

Explanation

The patient has a desmoid tumor (aggressive fibromatosis), characterized by beta-catenin (CTNNB1) mutations. Because of their unpredictable clinical course and tendency to stabilize or spontaneously regress, active observation is the preferred first-line management.

Question 6228

Topic: 10. Pathology and Oncology

A 6-year-old boy presents with a rapidly enlarging, painful mass over his scapula following a minor fall. Physical examination is notable for bilaterally shortened great toes with hallux valgus. Which of the following interventions is absolutely contraindicated in the initial management of this patient?

. Genetic testing for ACVR1 mutations
. Plain radiography of the scapula
. Incisional biopsy of the mass
. Administration of systemic corticosteroids
. Use of nonsteroidal anti-inflammatory drugs

Correct Answer & Explanation

. Incisional biopsy of the mass

Explanation

The clinical presentation (scapular mass post-trauma and short great toes) is classic for Fibrodysplasia Ossificans Progressiva (FOP). Incisional biopsy or surgical trauma is strictly contraindicated as it will trigger explosive heterotopic ossification.

Question 6229

Topic: 10. Pathology and Oncology

A 35-year-old female presents with a recurrent bloody knee effusion. MRI demonstrates a nodular intra-articular mass with low signal intensity on both T1- and T2-weighted images, and a "blooming" artifact on gradient-echo sequences. Which targeted systemic therapy is FDA-approved for severe, unresectable cases of this disease?

. Imatinib
. Pexidartinib
. Sorafenib
. Denosumab
. Crizotinib

Correct Answer & Explanation

. Pexidartinib

Explanation

The diagnosis is Pigmented Villonodular Synovitis (PVNS), now termed Tenosynovial Giant Cell Tumor (TGCT), driven by a CSF1 translocation. Pexidartinib is a CSF1 receptor inhibitor approved for severe cases not amenable to surgical resection.

Question 6230

Topic: 10. Pathology and Oncology

A 65-year-old male presents with a rapidly growing mass in his lateral thigh. He has a history of receiving external beam radiation therapy to the same extremity 15 years ago. Biopsy reveals highly pleomorphic spindle cells with bizarre multinucleated giant cells and atypical mitoses, but immunohistochemistry fails to show a specific line of differentiation. What is the most likely diagnosis?

. Leiomyosarcoma
. Fibrosarcoma
. Undifferentiated pleomorphic sarcoma (UPS)
. Myxoid liposarcoma
. Epithelioid sarcoma

Correct Answer & Explanation

. Undifferentiated pleomorphic sarcoma (UPS)

Explanation

Undifferentiated pleomorphic sarcoma (UPS), formerly known as Malignant Fibrous Histiocytoma (MFH), is the most common soft tissue sarcoma in adults and the most frequent histologic subtype of radiation-induced soft tissue sarcoma.

Question 6231

Topic: 10. Pathology and Oncology

A 14-year-old boy presents with a rapidly expanding calf mass. Biopsy reveals a primitive small round blue cell tumor. Molecular testing confirms a t(2;13)(q35;q14) translocation producing a PAX3-FOXO1 fusion gene. Which of the following describes this condition?

. Embryonal rhabdomyosarcoma with a favorable prognosis
. Embryonal rhabdomyosarcoma with a poor prognosis
. Alveolar rhabdomyosarcoma with a favorable prognosis
. Alveolar rhabdomyosarcoma with a poor prognosis
. Pleomorphic rhabdomyosarcoma with a variable prognosis

Correct Answer & Explanation

. Alveolar rhabdomyosarcoma with a poor prognosis

Explanation

The t(2;13) and t(1;13) translocations are diagnostic of alveolar rhabdomyosarcoma. The alveolar subtype carries a significantly worse prognosis and higher rate of metastasis compared to the more common embryonal subtype.

Question 6232

Topic: 10. Pathology and Oncology



A 55-year-old male undergoes a limb-sparing marginal excision for a high-grade, 8 cm soft tissue sarcoma of the deep thigh. Final pathology confirms negative margins, with normal muscle measuring 1 mm at the closest point. Based on standard sarcoma treatment protocols, what is the most appropriate adjuvant therapy to minimize local recurrence?

. Postoperative external beam radiation therapy
. Adjuvant systemic multi-agent chemotherapy
. Isolated limb perfusion with melphalan
. Immediate surgical re-excision to achieve 2 cm margins
. Active observation with serial MRIs

Correct Answer & Explanation

. Postoperative external beam radiation therapy

Explanation

For large (>5 cm), deep, high-grade soft tissue sarcomas treated with limb-sparing surgery and close margins, perioperative (neoadjuvant or adjuvant) external beam radiation therapy is the standard of care to maximize local control.

Question 6233

Topic: Bone Tumors
A 12-year-old girl presents with precocious puberty, irregular 'coast of Maine' café-au-lait spots, and a progressive proximal femur deformity. Radiographs reveal expansile, ground-glass lesions in the femur and pelvis. What is the underlying molecular pathogenesis of her skeletal condition?
. Mutation in the EXT1 gene leading to defective heparan sulfate synthesis
. Activating mutation of the GNAS1 gene leading to increased intracellular cAMP
. Mutation in the FGFR3 gene leading to abnormal endochondral ossification
. Defect in type I collagen synthesis leading to brittle bone matrix

Correct Answer & Explanation

. Activating mutation of the GNAS1 gene leading to increased intracellular cAMP

Explanation

This patient presents with McCune-Albright syndrome, characterized by the triad of polyostotic fibrous dysplasia, precocious puberty (or other endocrinopathies), and café-au-lait spots with irregular borders ('coast of Maine'). The underlying cause is a post-zygotic somatic activating mutation in the GNAS1 gene, which encodes the alpha subunit of the stimulatory G protein (Gs). This leads to constitutive activation of adenylate cyclase and elevated intracellular cyclic AMP (cAMP), resulting in abnormal proliferation and differentiation of preosteoblasts.

Question 6234

Topic: 10. Pathology and Oncology

A 25-year-old male presents with multiple asymmetric cartilaginous lesions in the tubular bones of his hands and feet, accompanied by multiple bluish, compressible subcutaneous nodules. Which of the following is the most significant long-term complication associated with this specific syndrome?

. Spontaneous resolution of the skeletal lesions after skeletal maturity
. Development of congenital pseudoarthrosis of the tibia
. High risk of malignant transformation to chondrosarcoma and visceral malignancies
. Obligatory progression to osteosarcoma in the affected digits

Correct Answer & Explanation

. High risk of malignant transformation to chondrosarcoma and visceral malignancies

Explanation

Correct Answer: High risk of malignant transformation to chondrosarcoma and visceral malignanciesThe clinical presentation of multiple enchondromas associated with soft tissue hemangiomas (bluish subcutaneous nodules) is diagnostic of Maffucci syndrome. Unlike Ollier disease (multiple enchondromatosis alone), Maffucci syndrome carries a significantly higher risk of malignant transformation. Patients have an estimated 20-30% (up to 100% in some long-term follow-up studies) risk of developing chondrosarcoma, as well as a high risk of developing visceral malignancies (e.g., astrocytomas, gastrointestinal malignancies).

Question 6235

Topic: Bone Tumors

An 18-year-old patient with polyostotic fibrous dysplasia presents with a progressive 'shepherd's crook' deformity of the proximal femur and a recent pathological fracture. Which of the following is the most appropriate surgical stabilization principle for this patient?

. Curettage and packing with autologous cancellous bone graft
. Open reduction and internal fixation with a dynamic hip screw and side plate
. Valgus osteotomy and stabilization with a load-sharing intramedullary device
. Wide resection and endoprosthetic reconstruction of the proximal femur

Correct Answer & Explanation

. Valgus osteotomy and stabilization with a load-sharing intramedullary device

Explanation

Correct Answer: Valgus osteotomy and stabilization with a load-sharing intramedullary deviceThe surgical management of fibrous dysplasia, particularly the 'shepherd's crook' deformity of the proximal femur, requires careful consideration of the abnormal bone biology. Cortical and cancellous bone grafts are typically resorbed and replaced by dysplastic bone, making simple curettage and grafting ineffective. Plate fixation is prone to failure due to the poor quality of the dysplastic bone and the massive bending forces. The gold standard is correction of the mechanical axis (valgus osteotomy) combined with a load-sharing intramedullary device (e.g., reconstruction nail) to protect the entire length of the affected bone.

Question 6236

Topic: Soft Tissue Tumors & Metastasis
An incidental pelvic radiograph of a 40-year-old male reveals numerous small, well-defined, symmetric sclerotic foci clustered around the periarticular regions of the pelvis and proximal femurs. He is completely asymptomatic. If this patient has an associated syndromic skin manifestation, what is the most likely clinical finding?
. Café-au-lait spots with smooth borders
. Dermatofibromas (connective tissue nevi)
. Subcutaneous hemangiomas
. Plexiform neurofibromas

Correct Answer & Explanation

. Dermatofibromas (connective tissue nevi)

Explanation

The radiographic description of multiple small, symmetric, periarticular sclerotic foci in an asymptomatic patient is classic for Osteopoikilosis ('spotted bone disease'). When osteopoikilosis is associated with skin lesions, specifically connective tissue nevi (dermatofibromas lenticularis disseminata), the condition is known as Buschke-Ollendorff syndrome. This syndrome is inherited in an autosomal dominant pattern and is associated with mutations in the LEMD3 gene.

Question 6237

Topic: 10. Pathology and Oncology

A 7-year-old child presents with a leg length discrepancy and angular deformity of the right lower extremity. Radiographs show multiple radiolucent expansile lesions in the metaphyses and diaphyses of the right femur and tibia, with linear striations. The left leg is unaffected. Which of the following statements regarding this condition is true?

. It is inherited in an autosomal dominant pattern
. The lesions typically cross the open physis to involve the epiphysis
. It is associated with somatic mosaic mutations in the IDH1 or IDH2 genes
. Malignant transformation to osteosarcoma occurs in over 50% of cases

Correct Answer & Explanation

. It is associated with somatic mosaic mutations in the IDH1 or IDH2 genes

Explanation

Correct Answer: It is associated with somatic mosaic mutations in the IDH1 or IDH2 genesThe clinical picture describes Ollier disease (multiple enchondromatosis), characterized by multiple enchondromas that are often unilateral or asymmetric, causing growth disturbances and deformities. Ollier disease is not hereditary; it is caused by somatic mosaic mutations in the isocitrate dehydrogenase 1 (IDH1) or IDH2 genes. Enchondromas typically do not cross the open physis. The risk of malignant transformation (usually to chondrosarcoma, not osteosarcoma) is approximately 5-30%, not >50%.

Question 6238

Topic: 10. Pathology and Oncology

A 45-year-old female with known polyostotic fibrous dysplasia presents with a painless, slow-growing soft tissue mass in her right thigh. MRI reveals a well-circumscribed intramuscular mass with high T2 signal and low T1 signal. What is the most likely diagnosis of the soft tissue mass?

. Intramuscular lipoma
. Soft tissue sarcoma
. Intramuscular myxoma
. Hemangioma

Correct Answer & Explanation

. Intramuscular myxoma

Explanation

Correct Answer: Intramuscular myxomaThe association of polyostotic fibrous dysplasia with intramuscular myxomas is known as Mazabraud syndrome. These myxomas are benign, slow-growing, painless soft tissue tumors that typically present in middle age, often years after the diagnosis of fibrous dysplasia. On MRI, myxomas characteristically show low signal intensity on T1-weighted images and high signal intensity on T2-weighted images due to their high mucin and water content.

Question 6239

Topic: Bone Tumors

In the context of Multiple Hereditary Exostoses (MHE), which of the following cellular processes is primarily disrupted by the underlying genetic mutation?

. Fibroblast growth factor receptor signaling in the proliferative zone
. Synthesis of heparan sulfate proteoglycans in the Golgi apparatus
. Cyclic AMP production in preosteoblasts
. Formation of the osteoclast ruffled border

Correct Answer & Explanation

. Synthesis of heparan sulfate proteoglycans in the Golgi apparatus

Explanation

Correct Answer: Synthesis of heparan sulfate proteoglycans in the Golgi apparatusMultiple Hereditary Exostoses (MHE) is caused by autosomal dominant mutations in the EXT1 or EXT2 genes. These genes encode glycosyltransferases localized to the Golgi apparatus, which are essential for the polymerization and synthesis of heparan sulfate proteoglycans (HSPGs). Deficiency in HSPGs disrupts normal Indian hedgehog (Ihh) signaling and chondrocyte proliferation/differentiation at the growth plate, leading to the formation of osteochondromas.

Question 6240

Topic: Bone Tumors

A 12-year-old girl presents with a progressive 'shepherd's crook' deformity of the proximal femur and large, irregularly bordered hyperpigmented skin macules. Which of the following best describes the underlying molecular pathogenesis of her skeletal condition?

. Mutation in the EXT1 gene leading to heparan sulfate deficiency
. Gain-of-function mutation in the GNAS1 gene leading to increased intracellular cAMP
. Mutation in the FGFR3 gene causing constitutive activation of the receptor
. Defect in the CBFA1 (RUNX2) transcription factor affecting osteoblast differentiation
. Somatic mosaic mutation in the IDH1 gene leading to oncometabolite production

Correct Answer & Explanation

. Gain-of-function mutation in the GNAS1 gene leading to increased intracellular cAMP

Explanation

Correct Answer: Gain-of-function mutation in the GNAS1 gene leading to increased intracellular cAMPThis patient presents with classic signs of McCune-Albright syndrome (polyostotic fibrous dysplasia, 'coast of Maine' cafe-au-lait spots, and endocrine abnormalities). Fibrous dysplasia is caused by a somatic, gain-of-function mutation in the GNAS1 gene. This mutation affects the alpha subunit of the stimulatory G protein (Gs-alpha), leading to constitutive activation of adenylate cyclase and elevated intracellular cyclic AMP (cAMP). This anarchic development results in the replacement of normal bone with fibrous stroma and immature woven bone. EXT1 mutations cause Multiple Hereditary Exostoses. FGFR3 mutations cause Achondroplasia. CBFA1 mutations cause Cleidocranial Dysplasia. IDH1/2 mutations cause Enchondromatosis (Ollier/Maffucci).

Test Yourself

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

On this Page