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Soft Tissue Tumors & Metastasis MCQs

Practice Set 5 of 6

This practice set contains high-yield board review questions covering key concepts in Soft Tissue Tumors & Metastasis. Each clinical scenario is designed to test your diagnostic and management skills relevant to this subspecialty.

Question 81

Topic: Soft Tissue Tumors & Metastasis

A 35-year-old female presents with a swelling in the medial aspect of her arm. Which of the following clinical findings is most characteristic of a schwannoma?

. Resting pain that improves with movement
. Painless progressive motor weakness
. A palpable mass with a positive Tinel sign radiating distally
. A rapidly expanding mass with overlying skin necrosis
. A cold, pale distal extremity with absent pulses

Correct Answer & Explanation

. A palpable mass with a positive Tinel sign radiating distally

Explanation

Schwannomas often present as a slow-growing palpable mass. Tapping the mass frequently elicits a positive Tinel sign (paresthesias radiating along the nerve distribution).

Question 82

Topic: Soft Tissue Tumors & Metastasis

Which histological description is the classic hallmark of a neurofibroma?

. Antoni A and B regions
. Nuclear palisading forming Verocay bodies
. Wavy spindle cells with "shredded carrot" collagen in a myxoid matrix
. Epithelioid cells forming nests and cords
. Biphasic glandular and spindle cell elements

Correct Answer & Explanation

. Wavy spindle cells with "shredded carrot" collagen in a myxoid matrix

Explanation

Neurofibromas are characterized by wavy, serpentine spindle cells (Schwann cells and fibroblasts) set in a myxoid stroma. They classically feature thick, ropey collagen bundles known as "shredded carrot" collagen.

Question 83

Topic: Soft Tissue Tumors & Metastasis

While schwannomas are composed almost exclusively of neoplastic Schwann cells, what cell type combination forms the primary neoplastic component of a neurofibroma?

. Perineurial cells exclusively
. Schwann cells admixed with fibroblasts
. Mast cells exclusively
. Epineurial fibroblasts
. Endothelial cells

Correct Answer & Explanation

. Schwann cells admixed with fibroblasts

Explanation

Neurofibromas are heterogeneous tumors consisting of neoplastic Schwann cells admixed with fibroblasts, perineurial-like cells, and often numerous mast cells. This distinguishes them from the monotypic Schwann cell population of a schwannoma.

Question 84

Topic: Soft Tissue Tumors & Metastasis

A 45-year-old man has a large, painless mass deep in his posterior thigh. Histologic examination reveals uniform, small, round to oval cells, scattered lipoblasts, and a prominent arborizing capillary network described as 'chicken wire' vasculature in a myxoid background. Which translocation is diagnostic?

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

Correct Answer & Explanation

. t(12;16)

Explanation

Myxoid liposarcoma is characterized by the t(12;16) translocation creating the FUS-DDIT3 fusion protein. The 'chicken wire' capillary network is a classic histological hallmark.

Question 85

Topic: Soft Tissue Tumors & Metastasis

A 60-year-old man presents with severe back pain and a solitary L2 vertebral body metastasis secondary to renal cell carcinoma. He has impending cord compression, and his estimated life expectancy is 18 months. What is the most appropriate surgical treatment strategy?

. External beam radiation therapy alone
. Palliative posterior laminectomy without fusion
. Preoperative embolization followed by en bloc spondylectomy
. Vertebroplasty alone
. Corticosteroids and bracing

Correct Answer & Explanation

. External beam radiation therapy alone

Explanation

Renal cell carcinoma metastases are highly vascular and famously radioresistant. Therefore, optimal treatment for an isolated spinal metastasis requires preoperative embolization (to reduce bleeding) followed by wide excision or en bloc spondylectomy.

Question 86

Topic: Soft Tissue Tumors & Metastasis

Which liposarcoma subtype is characterized by prominent pleomorphic lipoblasts, bizarre giant cells, and atypical spindle cells, often without a significant myxoid component?

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

Correct Answer & Explanation

. Pleomorphic liposarcoma

Explanation

Pleomorphic liposarcoma is a high-grade sarcoma characterized by significant cellular pleomorphism, with highly atypical, bizarre giant cells and pleomorphic lipoblasts. It often lacks the prominent myxoid stroma of myxoid liposarcoma or the low-grade fatty components of well-differentiated liposarcoma. Distinguishing it from other undifferentiated pleomorphic sarcomas often relies on the definitive identification of pleomorphic lipoblasts.

Question 87

Topic: Soft Tissue Tumors & Metastasis

A 40-year-old woman presents with a soft, mobile, painless, subcutaneous mass on her forearm that has been present for several years and has not changed significantly in size. This description is most consistent with:

. Liposarcoma
. Ganglion cyst
. Epidermoid cyst
. Benign lipoma
. Neurofibroma

Correct Answer & Explanation

. Benign lipoma

Explanation

This clinical presentation is classic for a benign subcutaneous lipoma: a soft, mobile, painless, superficial mass that has been stable or slowly growing over a long period. Liposarcomas are more commonly deep, firm, and progressively enlarging. Ganglion and epidermoid cysts have different textures and etiologies. Neurofibromas can be soft but often have specific associated nerve symptoms or 'bag of worms' consistency.

Question 88

Topic: Soft Tissue Tumors & Metastasis

Which subtype of liposarcoma is generally considered most radiosensitive?

. Well-differentiated liposarcoma
. Dedifferentiated liposarcoma
. Myxoid liposarcoma
. Pleomorphic liposarcoma
. Spindle cell lipoma

Correct Answer & Explanation

. Myxoid liposarcoma

Explanation

Myxoid liposarcoma is recognized as being particularly radiosensitive compared to other sarcoma subtypes. This characteristic makes radiotherapy a crucial component of its management, often utilized in neoadjuvant (pre-operative) or adjuvant (post-operative) settings to improve local control and facilitate limb salvage.

Question 89

Topic: Soft Tissue Tumors & Metastasis

A patient presents with a large, rapidly growing retroperitoneal dedifferentiated liposarcoma. What is the cornerstone of treatment?

. Systemic chemotherapy alone
. Radiation therapy alone
. Aggressive surgical resection with negative margins
. Targeted therapy
. Observation and palliative care

Correct Answer & Explanation

. Aggressive surgical resection with negative margins

Explanation

For dedifferentiated liposarcomas (DDLPS), particularly in challenging locations like the retroperitoneum, aggressive surgical resection with the goal of achieving negative margins remains the cornerstone of treatment. While chemotherapy and radiation therapy may play important neoadjuvant or adjuvant roles to improve resectability or reduce local recurrence, complete surgical removal offers the best chance for local control and improved survival. DDLPS is often resistant to chemotherapy alone.

Question 90

Topic: Soft Tissue Tumors & Metastasis

Which subtype of liposarcoma, often considered a high-grade variant, is characterized by a significant proportion of primitive, small round cells in addition to myxoid areas and plexiform capillaries?

. Well-differentiated liposarcoma
. Pleomorphic liposarcoma
. Myxoid liposarcoma with a round cell component
. Dedifferentiated liposarcoma
. Spindle cell lipoma

Correct Answer & Explanation

. Myxoid liposarcoma with a round cell component

Explanation

Myxoid liposarcoma is graded based on its cellularity, specifically the percentage of round cells within the myxoid stroma. A significant 'round cell component' (e.g., >5% or >25% depending on the specific grading system) indicates a higher-grade myxoid liposarcoma, which has a worse prognosis and higher metastatic potential than its low-grade counterpart. These round cells are primitive, undifferentiated cells.

Question 91

Topic: Soft Tissue Tumors & Metastasis

Myxoid liposarcoma commonly occurs in which anatomical location?

. Subcutaneous tissue of the trunk
. Head and neck region
. Retroperitoneum
. Deep soft tissues of the lower extremities (e.g., thigh)
. Hands and feet

Correct Answer & Explanation

. Deep soft tissues of the lower extremities (e.g., thigh)

Explanation

Myxoid liposarcoma is the second most common subtype of liposarcoma and has a strong predilection for the deep soft tissues of the lower extremities, particularly the thigh. While well-differentiated and dedifferentiated liposarcomas are frequently found in the retroperitoneum, myxoid liposarcomas are predominantly limb-based.

Question 92

Topic: Soft Tissue Tumors & Metastasis

What is the characteristic histological appearance of a lipoblast, a key diagnostic cell in liposarcoma?

. Small, round cell with scant cytoplasm and hyperchromatic nucleus
. Spindle-shaped cell with wavy nuclei and eosinophilic cytoplasm
. Large, polygonal cell with abundant clear cytoplasm and central nucleus
. Multivacuolated cell with scalloped, eccentric nucleus, resembling a signet ring
. Foamy macrophage with lipid droplets

Correct Answer & Explanation

. Multivacuolated cell with scalloped, eccentric nucleus, resembling a signet ring

Explanation

A true lipoblast, a hallmark cell of liposarcoma, is a neoplastic immature fat cell. It is characterized by one or more cytoplasmic lipid vacuoles that indent and scallop the nucleus. A univacuolated lipoblast has a single large vacuole pushing the nucleus to the periphery, resembling a signet ring cell, while a multivacuolated lipoblast has multiple smaller vacuoles, all indenting the nucleus. This distinguishes it from mature adipocytes or lipid-laden macrophages.

Question 93

Topic: Soft Tissue Tumors & Metastasis

In which scenario might primary amputation be considered as the initial treatment for a liposarcoma?

. Small (<3cm), low-grade superficial liposarcoma
. Large, low-grade retroperitoneal liposarcoma
. High-grade liposarcoma with no evidence of neurovascular involvement
. Extremely large, high-grade liposarcoma with extensive neurovascular involvement, where limb salvage is unlikely
. Myxoid liposarcoma after neoadjuvant chemotherapy

Correct Answer & Explanation

. Extremely large, high-grade liposarcoma with extensive neurovascular involvement, where limb salvage is unlikely

Explanation

Limb salvage surgery is the preferred approach for most soft tissue sarcomas. However, primary amputation may be considered as the initial treatment for an extremely large, high-grade liposarcoma with extensive invasion of critical neurovascular structures or bone, where achieving negative margins with functional limb salvage is deemed impossible or would result in a limb less functional than a well-fitted prosthesis. In other scenarios, limb salvage is typically attempted first, often with neoadjuvant therapies.

Question 94

Topic: Soft Tissue Tumors & Metastasis

A 25-year-old male presents with recurrent acute attacks of severe back and leg pain, followed by periods of remission. MRI reveals multiple well-circumscribed, enhancing intradural-extramedullary lesions in the lumbar spine, some with a cystic component. These lesions are T1 isointense and T2 hyperintense. What is the most likely diagnosis?

. Multiple Meningiomas
. Multiple Schwannomas
. Spinal Neurofibromatosis Type 1
. Spinal Hemangioblastomatosis
. Disseminated Ependymomatosis

Correct Answer & Explanation

. Multiple Schwannomas

Explanation

Multiple schwannomas (schwannomatosis) can present with recurrent attacks of pain and are typically intradural-extramedullary, well-circumscribed, and enhancing. The cystic component is also common in schwannomas. While neurofibromatosis can involve multiple nerve sheath tumors, schwannomatosis specifically refers to multiple schwannomas without evidence of NF2. Multiple meningiomas are rare in young adults without NF2. Hemangioblastomas are often intramedullary and associated with VHL disease. Disseminated ependymomatosis is rare and would typically be intramedullary in origin or CSF spread from a primary ependymoma.

Question 95

Topic: Soft Tissue Tumors & Metastasis

A 55-year-old male with a history of renal cell carcinoma presents with a large, solitary, highly destructive lytic lesion in the proximal diaphyseal femur with an impending pathologic fracture. What is the most critical step prior to proceeding with prophylactic intramedullary stabilization?

. Immediate intramedullary nailing within 24 hours
. Initiation of systemic chemotherapy prior to surgery
. Preoperative angiographic embolization of the lesion
. Neoadjuvant external beam radiation therapy
. Wide local excision and massive endoprosthetic reconstruction

Correct Answer & Explanation

. Preoperative angiographic embolization of the lesion

Explanation

Renal cell carcinoma metastases to bone are highly vascular and prone to massive intraoperative hemorrhage. Preoperative angiographic embolization is strictly recommended within 24-48 hours prior to surgical stabilization to reduce life-threatening blood loss.

Question 96

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 97

Topic: Soft Tissue Tumors & Metastasis
An asymptomatic 25-year-old man undergoes a pelvic radiograph following minor trauma, which reveals numerous small, well-defined, symmetric sclerotic foci clustered around the joints. If this skeletal finding is part of a syndrome, what associated skin manifestation might be present?
. Café-au-lait spots with irregular borders
. Soft tissue hemangiomas
. Connective tissue nevi (dermatofibrosis lenticularis disseminata)
. Subcutaneous neurofibromas

Correct Answer & Explanation

. Connective tissue nevi (dermatofibrosis lenticularis disseminata)

Explanation

The radiographic description is classic for osteopoikilosis ('spotted bone disease'). When osteopoikilosis is associated with skin lesions, it is known as Buschke-Ollendorff syndrome. The characteristic skin lesions are connective tissue nevi, also known as dermatofibrosis lenticularis disseminata. This autosomal dominant condition is caused by loss-of-function mutations in the LEMD3 gene.

Question 98

Topic: Soft Tissue Tumors & Metastasis
An incidental pelvic radiograph of a 25-year-old female reveals numerous small, well-defined, symmetric sclerotic foci clustered around the periarticular regions of the hips and pelvis. She is asymptomatic. If this skeletal finding is part of a syndrome, which of the following dermatological manifestations is most likely to be present?
. Café-au-lait spots with smooth borders
. Café-au-lait spots with irregular 'coast of Maine' borders
. Connective tissue nevi
. Subcutaneous hemangiomas
. Multiple neurofibromas

Correct Answer & Explanation

. Connective tissue nevi

Explanation

The radiographic findings describe Osteopoikilosis ('spotted bone disease'), an asymptomatic, autosomal dominant sclerosing dysplasia. When osteopoikilosis is associated with disseminated connective tissue nevi (dermatofibrosis lenticularis disseminata), the condition is known as Buschke-Ollendorff syndrome. Both isolated osteopoikilosis and Buschke-Ollendorff syndrome are linked to mutations in the LEMD3 gene.

Question 99

Topic: Soft Tissue Tumors & Metastasis
A 30-year-old patient has routine radiographs following minor trauma that reveal numerous small, symmetric, well-defined sclerotic bone lesions clustered around the periarticular regions of the pelvis and long bones. What associated skin finding is most commonly seen with this condition?
. Café-au-lait macules
. Dermatofibrosis lenticularis disseminata
. Subcutaneous neurofibromas
. Port-wine stains
. Hemangiomas

Correct Answer & Explanation

. Dermatofibrosis lenticularis disseminata

Explanation

Osteopoikilosis (spotted bone disease) is an asymptomatic sclerosing bone dysplasia associated with LEMD3 mutations. It is classically associated with dermatofibrosis lenticularis disseminata (Buschke-Ollendorff syndrome), presenting as connective tissue nevi.

Question 100

Topic: Soft Tissue Tumors & Metastasis

A 65-year-old man undergoes resection of a massive, deep intramuscular thigh mass. Pathology demonstrates a dedifferentiated liposarcoma. Which molecular marker is most characteristically amplified in well-differentiated and dedifferentiated liposarcomas?

. c-MYC
. HER2
. MDM2
. p53
. BRAF

Correct Answer & Explanation

. MDM2

Explanation

Well-differentiated and dedifferentiated liposarcomas are characterized by supernumerary ring and giant marker chromosomes containing amplification of the 12q13-15 region. This leads to the characteristic over-expression/amplification of MDM2 and CDK4.

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