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10. Pathology and Oncology MCQs

Practice Set 310 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 6181

Topic: 10. Pathology and Oncology

A 45-year-old male presents with chronic knee pain, catching, and locking. Radiographs show multiple intra-articular calcified loose bodies of relatively uniform size.

What is the underlying pathophysiology of this condition?

. Synovial metaplasia
. Microtrauma leading to osteochondral fragmentation
. Deposition of calcium pyrophosphate crystals
. Autoimmune synovial proliferation
. Malignant transformation of synovium

Correct Answer & Explanation

. Synovial metaplasia

Explanation

Synovial chondromatosis is a benign condition caused by metaplasia of the synovium into cartilage, which can later ossify. The uniform size of the loose bodies differentiates it from degenerative joint disease fragmentation.

Question 6182

Topic: 10. Pathology and Oncology

What is the most important prognostic factor for overall survival in a patient presenting with a localized high-grade soft tissue sarcoma of the extremity?

. Tumor size
. Depth of the tumor (superficial vs deep)
. Histologic grade
. Proximity to neurovascular bundle
. Patient age

Correct Answer & Explanation

. Histologic grade

Explanation

Histologic grade is the most significant prognostic factor for overall survival and distant metastasis in soft tissue sarcomas. Size and depth are also important staging criteria but are secondary to grade in predicting survival.

Question 6183

Topic: 10. Pathology and Oncology

A 55-year-old female has an 8 cm deep, firm, painless mass in her anterior thigh.

A core needle biopsy is planned. Which of the following is an essential principle of the biopsy technique?

. The biopsy tract should be placed transversely across the extremity
. The biopsy tract must be excisable during the definitive resection
. Extensive surgical dissection is necessary to obtain adequate margins during biopsy
. The biopsy should be performed through the joint capsule if adjacent
. A tourniquet should be inflated and deflated before the biopsy is complete

Correct Answer & Explanation

. The biopsy tract must be excisable during the definitive resection

Explanation

The biopsy tract is considered contaminated with tumor cells and must be placed longitudinally so it can be excised entirely en bloc during definitive surgery. Transverse incisions complicate the final resection and may necessitate a larger soft tissue defect.

Question 6184

Topic: 10. Pathology and Oncology

A 30-year-old male presents with a slowly growing, painful mass near his knee. MRI shows a soft tissue mass with multi-locular fluid-fluid levels adjacent to the joint. Biopsy shows a biphasic pattern of epithelial and spindle cells. What is the characteristic chromosomal translocation?

. t(X;18)
. t(11;22)
. t(12;16)
. t(2;13)
. 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 often presents in young adults as a painful mass near (but rarely within) a joint.

Question 6185

Topic: 10. Pathology and Oncology

A 28-year-old female presents with a deep soft tissue mass in the foot attached to the plantar aponeurosis. Histology is positive for S-100 and HMB-45. This tumor shares its histological markers with which of the following?

. Rhabdomyosarcoma
. Malignant peripheral nerve sheath tumor
. Melanoma
. Epithelioid sarcoma
. Liposarcoma

Correct Answer & Explanation

. Melanoma

Explanation

Clear cell sarcoma is also known as melanoma of soft parts and stains positive for melanin markers (S-100, HMB-45). It frequently involves the foot and ankle aponeuroses in young adults.

Question 6186

Topic: 10. Pathology and Oncology

A 24-year-old female presents with a painless, slow-growing mass in her right thigh. Staging reveals multiple pulmonary metastases. Biopsy shows large cells with crystalline intracytoplasmic inclusions that are PAS-positive and diastase-resistant. What is the most likely diagnosis?

. Synovial sarcoma
. Alveolar soft part sarcoma
. Epithelioid sarcoma
. Clear cell sarcoma
. Angiosarcoma

Correct Answer & Explanation

. Alveolar soft part sarcoma

Explanation

Alveolar soft part sarcoma uniquely presents with PAS-positive, diastase-resistant intracellular crystals. It has a high rate of early metastasis, particularly to the lungs and brain, despite indolent growth.

Question 6187

Topic: Bone Tumors
A 9-year-old girl presents with a proximal femur fracture. Radiographs show a "ground-glass" appearance in the proximal femur. She is noted to have precocious puberty and café-au-lait spots with irregular borders. Which mutation is responsible for this condition?
. GNAS1
. EXT1
. NF1
. FGFR3
. COL1A1

Correct Answer & Explanation

. GNAS1

Explanation

McCune-Albright syndrome is a triad of polyostotic fibrous dysplasia, endocrinopathies (precocious puberty), and coast-of-Maine café-au-lait spots. It is caused by a somatic activating mutation in the GNAS1 gene.

Question 6188

Topic: 10. Pathology and Oncology

Which subtype of liposarcoma commonly occurs in the retroperitoneum or deep thigh, has a low propensity for distant metastasis, but frequently recurs locally if not completely excised?

. Myxoid liposarcoma
. Round cell liposarcoma
. Pleomorphic liposarcoma
. Well-differentiated liposarcoma
. Dedifferentiated liposarcoma

Correct Answer & Explanation

. Well-differentiated liposarcoma

Explanation

Well-differentiated liposarcoma (atypical lipomatous tumor) has minimal metastatic potential but tends to recur locally if incompletely excised. It characteristically features MDM2 and CDK4 amplification.

Question 6189

Topic: 10. Pathology and Oncology

A 25-year-old male presents with a non-healing, painless ulcer on the volar aspect of his forearm. The mass extends proximally along the lymphatic tracks. Which soft tissue sarcoma is most likely responsible for this presentation?

. Fibrosarcoma
. Epithelioid sarcoma
. Synovial sarcoma
. Dermatofibrosarcoma protuberans
. Kaposi sarcoma

Correct Answer & Explanation

. Epithelioid sarcoma

Explanation

Epithelioid sarcoma often presents as a superficial nodule or non-healing ulceration on the distal extremities of young adults. It is notable for its tendency to spread via regional lymphatics.

Question 6190

Topic: 10. Pathology and Oncology

A 60-year-old man underwent wide surgical excision of a 10 cm high-grade pleomorphic sarcoma of the deep posterior thigh. Final pathology margins were negative (R0). Which of the following adjuvant therapies is most indicated to maximize local control?

. Neoadjuvant targeted immunotherapy
. Postoperative external beam radiation therapy
. Postoperative multi-agent chemotherapy
. Isolated limb perfusion
. Observation with serial MRIs

Correct Answer & Explanation

. Postoperative external beam radiation therapy

Explanation

For deep, high-grade, large (>5 cm) soft tissue sarcomas, adjuvant radiation therapy (pre- or postoperative) is the standard of care to maximize local control. It significantly decreases local recurrence rates compared to surgery alone.

Question 6191

Topic: 10. Pathology and Oncology

A 40-year-old male presents with a large soft tissue mass in his thigh. Biopsy shows a plexiform "chicken-wire" capillary network with lipoblasts. Which chromosomal translocation is pathognomonic for this tumor?

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

Correct Answer & Explanation

. t(12;16)

Explanation

Myxoid liposarcoma is characterized by the t(12;16) translocation resulting in the FUS-DDIT3 (TLS-CHOP) fusion gene. It is known to spread to extrapulmonary bony sites, such as the spine.

Question 6192

Topic: 10. Pathology and Oncology

A 35-year-old female presents with a nodular, plaque-like cutaneous mass on her trunk. Pathology reveals a "cartwheel" or "storiform" pattern of spindle cells staining positive for CD34. What is the surgical treatment of choice?

. Marginal excision
. Wide local excision with Mohs micrographic surgery or 2-3 cm margins
. Amputation
. Intralesional curettage
. Primary radiation therapy

Correct Answer & Explanation

. Wide local excision with Mohs micrographic surgery or 2-3 cm margins

Explanation

Dermatofibrosarcoma protuberans (DFSP) is a locally aggressive tumor with high recurrence rates. It requires wide surgical margins (2-3 cm) or Mohs micrographic surgery to achieve negative margins and prevent recurrence.

Question 6193

Topic: 10. Pathology and Oncology

A 32-year-old woman presents with recurrent hemorrhagic effusions of the knee. MRI shows a villous synovial mass with "blooming artifact" on gradient-echo sequences due to hemosiderin. Which targeted therapy is FDA-approved for severe, refractory cases of this disease?

. Imatinib
. Denosumab
. Pexidartinib
. Sorafenib
. Doxorubicin

Correct Answer & Explanation

. Pexidartinib

Explanation

Tenosynovial giant cell tumor (formerly PVNS) is driven by an over-expression of CSF1. Pexidartinib is a CSF1 receptor inhibitor FDA-approved for symptomatic, severe cases not amenable to surgical improvement.

Question 6194

Topic: 10. Pathology and Oncology

A 65-year-old male with a history of renal cell carcinoma presents with a lytic lesion in the proximal femur causing severe pain.

Prophylactic fixation is planned. What is a critical preoperative step specific to managing bony metastases from this primary tumor?

. Preoperative radiation therapy
. Preoperative embolization
. Systemic bisphosphonate administration 1 week prior
. Biopsy confirming the exact histologic subtype
. Initiation of empiric chemotherapy

Correct Answer & Explanation

. Preoperative embolization

Explanation

Renal cell carcinoma (and thyroid carcinoma) bone metastases are highly vascular. Preoperative embolization is strongly recommended 24 to 48 hours prior to surgical stabilization to reduce massive intraoperative blood loss.

Question 6195

Topic: 10. Pathology and Oncology

A 55-year-old male presents with a painless, deep, 8 cm mass in his posterior thigh. MRI shows a heterogeneous soft tissue lesion deep to the fascia.

Which of the following is the most appropriate next step in establishing a definitive diagnosis?

. Fine needle aspiration (FNA)
. Core needle biopsy
. Marginal excisional biopsy
. Primary neoadjuvant radiation
. Open incisional biopsy oriented transversely

Correct Answer & Explanation

. Core needle biopsy

Explanation

Core needle biopsy is the standard of care for diagnosing soft tissue masses greater than 5 cm or deep to the fascia. It provides sufficient tissue for histologic architecture and molecular testing while minimizing the risk of track seeding.

Question 6196

Topic: 10. Pathology and Oncology

A 25-year-old male is evaluated for a slow-growing, painful mass adjacent to his knee joint. Histopathological analysis reveals a biphasic tumor consisting of both epithelial and spindle cells. What is the characteristic chromosomal translocation associated with this pathology?

. t(11;22) (EWS-FLI1)
. t(12;16) (FUS-CHOP)
. t(X;18) (SYT-SSX)
. t(2;13) (PAX3-FKHR)
. t(9;22) (BCR-ABL)

Correct Answer & Explanation

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

Explanation

Synovial sarcoma is highly associated with the specific chromosomal translocation t(X;18), which fuses the SYT gene with an SSX gene. This molecular finding is diagnostic and drives tumor pathogenesis.

Question 6197

Topic: 10. Pathology and Oncology

A 35-year-old female undergoes resection of a deep thigh mass. Histology demonstrates a prominent plexiform capillary network and lipoblasts in a myxoid stroma. In addition to the lungs, what is the most critical extrapulmonary site for metastasis screening in this specific tumor type?

. Brain
. Liver
. Spine/Bone
. Lymph nodes
. Kidneys

Correct Answer & Explanation

. Spine/Bone

Explanation

Myxoid liposarcoma has a unique and highly characteristic propensity to metastasize to the skeletal system, particularly the spine. Staging and follow-up must include whole-spine MRI or bone scans.

Question 6198

Topic: 10. Pathology and Oncology

A 20-year-old female presents with a painless, slow-growing mass in her anterior thigh. Biopsy shows large cells with abundant eosinophilic cytoplasm and PAS-positive, diastase-resistant crystalline inclusions. Which of the following describes the typical clinical behavior of this tumor?

. It frequently metastasizes to the brain
. It is extremely responsive to conventional chemotherapy
. It primarily arises from normal alveolar epithelial cells
. It carries an excellent prognosis with marginal excision
. It is characterized by rapid, explosive local growth

Correct Answer & Explanation

. It frequently metastasizes to the brain

Explanation

Alveolar soft part sarcoma is notorious for its slow clinical growth but highly aggressive metastatic potential. It frequently metastasizes to the lungs and brain, requiring careful systemic staging.

Question 6199

Topic: 10. Pathology and Oncology

A 32-year-old woman presents with a firm mass in the rectus abdominis muscle. Biopsy confirms aggressive fibromatosis (desmoid tumor) showing a clonal proliferation of uniform fibroblasts with abundant collagen. Intra-abdominal variants of this tumor are strongly associated with which of the following syndromes?

. Neurofibromatosis type 1
. Li-Fraumeni syndrome
. Familial adenomatous polyposis
. McCune-Albright syndrome
. Ollier disease

Correct Answer & Explanation

. Familial adenomatous polyposis

Explanation

Desmoid tumors (aggressive fibromatosis) arise sporadically but are strongly associated with Familial Adenomatous Polyposis (Gardner syndrome), particularly for intra-abdominal and mesenteric lesions.

Question 6200

Topic: 10. Pathology and Oncology

A 65-year-old male presents with a rapidly enlarging painless mass in the posterior thigh. Biopsy shows highly atypical, pleomorphic spindle cells with frequent atypical mitoses, but lacks specific differentiation.

Which of the following is true regarding Undifferentiated Pleomorphic Sarcoma (UPS)?

. It features a specific highly sensitive diagnostic translocation.
. It is a diagnosis of exclusion after ruling out specific high-grade sarcomas.
. It is the most common soft tissue sarcoma in pediatric patients.
. It originates exclusively from mature skeletal muscle fibers.
. It typically presents as a well-circumscribed, low-grade lesion.

Correct Answer & Explanation

. It is a diagnosis of exclusion after ruling out specific high-grade sarcomas.

Explanation

Undifferentiated Pleomorphic Sarcoma (formerly malignant fibrous histiocytoma) represents a high-grade pleomorphic neoplasm. It is a diagnosis of exclusion made when a specific lineage of differentiation cannot be established.

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