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10. Pathology and Oncology MCQs

Practice Set 160 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 3181

Topic: 10. Pathology and Oncology

A 14-year-old male presents with chronic knee pain. Radiographs reveal a 2 cm well-circumscribed, lytic lesion in the distal femoral epiphysis with a sclerotic margin. Biopsy shows polyhedral mononuclear cells and "chicken wire" calcifications. What is the diagnosis?

. Giant cell tumor
. Chondroblastoma
. Clear cell chondrosarcoma
. Osteoblastoma
. Aneurysmal bone cyst

Correct Answer & Explanation

. Chondroblastoma

Explanation

Chondroblastoma is a rare benign bone tumor that classically occurs in the epiphysis or apophysis of growing children. Histologically, it is characterized by mononuclear chondroblasts, osteoclast-like giant cells, and distinctive "chicken wire" pericellular calcifications.

Question 3182

Topic: 10. Pathology and Oncology

A 40-year-old male complains of a chronic, painless, swollen right knee. MRI demonstrates a frond-like synovial mass.

What is the characteristic MRI finding that confirms this diagnosis?

. Low signal on T1 and T2 with prominent blooming artifact on GRE
. High signal on T1 and T2 that drops out completely on STIR sequences
. Isointense to muscle on T1 with intense homogenous gadolinium enhancement
. Multilocular cystic lesions demonstrating prominent fluid-fluid levels
. High signal on T2 with a characteristic central dot sign

Correct Answer & Explanation

. High signal on T1 and T2 that drops out completely on STIR sequences

Explanation

Lipoma arborescens consists of mature fat expanding the subsynovial tissue. Therefore, it follows the signal intensity of subcutaneous fat on all MRI sequences, displaying high signal on T1/T2 and suppressing on fat-saturated (STIR) images.

Question 3183

Topic: 10. Pathology and Oncology

Which histologic description best characterizes the lesion known as lipoma arborescens?

. Mononuclear stromal cells mixed with multinucleated giant cells and hemosiderin
. Nodular proliferation of disorganized hyaline cartilage within the synovium
. Subsynovial replacement by mature adipocytes with prominent villous proliferation
. Malignant lipoblasts with pleomorphic nuclei and mitotic figures
. Granulomatous inflammation with central caseating necrosis

Correct Answer & Explanation

. Subsynovial replacement by mature adipocytes with prominent villous proliferation

Explanation

Histologically, lipoma arborescens is identified by the massive replacement of subsynovial connective tissue by mature adipocytes. It presents as a villous or frond-like proliferation without cellular atypia or malignancy.

Question 3184

Topic: Soft Tissue Tumors & Metastasis

When attempting to differentiate lipoma arborescens from pigmented villonodular synovitis (PVNS) on MRI, which feature is highly specific for PVNS?

. Location in the suprapatellar pouch
. High signal intensity on T1-weighted images
. Low signal on T2-weighted images with blooming artifact on gradient-echo
. Suppression of signal on fat-saturated sequences
. Frond-like synovial projections

Correct Answer & Explanation

. Low signal on T2-weighted images with blooming artifact on gradient-echo

Explanation

PVNS is characterized by hemosiderin deposition, which appears as low signal on T2-weighted images and causes "blooming" artifact on gradient-echo (GRE) sequences. Lipoma arborescens lacks hemosiderin and follows fat signal.

Question 3185

Topic: Soft Tissue Tumors & Metastasis

Which of the following joint conditions is most commonly associated with the development of secondary lipoma arborescens?

. Rheumatoid arthritis
. Osteoarthritis
. Pigmented villonodular synovitis
. Synovial chondromatosis
. Lyme disease

Correct Answer & Explanation

. Osteoarthritis

Explanation

While lipoma arborescens can be primary, it is most often a secondary, reactive process resulting from chronic synovial irritation. It is most frequently associated with underlying degenerative joint disease (osteoarthritis) or prior trauma.

Question 3186

Topic: Soft Tissue Tumors & Metastasis

A 45-year-old male presents with chronic, painless, boggy swelling of the left knee. An MRI is obtained. Based on the likely diagnosis of Lipoma Arborescens, what is the classic MRI finding?

. Low signal on T1, high signal on T2, hyperintense on STIR
. High signal on T1, high signal on T2, complete suppression on fat-saturated sequences
. Low signal on T1, low signal on T2 with blooming artifact on gradient echo
. High signal on T1, low signal on T2, hyperintense on STIR
. Intermediate signal on T1 and T2 with avid contrast enhancement

Correct Answer & Explanation

. High signal on T1, high signal on T2, complete suppression on fat-saturated sequences

Explanation

Lipoma arborescens follows fat signal on all MRI sequences, showing high signal on T1 and T2, and complete signal loss on fat-suppressed (STIR or Fat-Sat) sequences. Blooming artifact would suggest Pigmented Villonodular Synovitis (PVNS).

Question 3187

Topic: 10. Pathology and Oncology

Which of the following histological descriptions is diagnostic for Lipoma Arborescens?

. Multinucleated giant cells with hemosiderin-laden macrophages
. Villous proliferation of the synovial membrane with replacement of subsynovial tissue by mature adipocytes
. Hyperplastic synovium with prominent lymphoid follicles and plasma cells
. Malignant lipoblasts with cellular atypia and frequent mitoses
. Deposition of rhomboid-shaped, positively birefringent crystals in the synovium

Correct Answer & Explanation

. Villous proliferation of the synovial membrane with replacement of subsynovial tissue by mature adipocytes

Explanation

Lipoma arborescens is characterized by a villous or frond-like proliferation of the synovium, where the subsynovial connective tissue is entirely replaced by mature adipocytes without atypia.

Question 3188

Topic: Soft Tissue Tumors & Metastasis

Lipoma arborescens is most frequently associated with which of the following underlying conditions?

. Rheumatoid arthritis
. Pigmented villonodular synovitis (PVNS)
. Degenerative joint disease (Osteoarthritis)
. Ankylosing spondylitis
. Systemic lupus erythematosus

Correct Answer & Explanation

. Degenerative joint disease (Osteoarthritis)

Explanation

While lipoma arborescens can be idiopathic, it is most commonly a reactive process associated with degenerative joint disease (osteoarthritis) or chronic mechanical irritation.

Question 3189

Topic: Soft Tissue Tumors & Metastasis

Which anatomic location is most commonly affected by Lipoma Arborescens?

. Subacromial bursa of the shoulder
. Olecranon bursa of the elbow
. Suprapatellar pouch of the knee
. Radiocarpal joint of the wrist
. Tibiotalar joint of the ankle

Correct Answer & Explanation

. Suprapatellar pouch of the knee

Explanation

Lipoma arborescens predominantly affects the knee joint, with the suprapatellar pouch being the most frequent and characteristic site of involvement.

Question 3190

Topic: 10. Pathology and Oncology

A 35-year-old male presents with chronic, painless swelling of the right knee. MRI demonstrates a frond-like mass in the suprapatellar pouch.

Which of the following MRI characteristics is pathognomonic for this condition?

. Hyperintensity on T1 sequences that enhances with gadolinium
. Low signal intensity on T1 and T2 sequences
. Fluid-fluid levels on T2 sequences
. Hyperintense signal on T1 that completely suppresses on fat-saturated sequences
. Hypointense signal on T1 with peripheral enhancement

Correct Answer & Explanation

. Hyperintense signal on T1 that completely suppresses on fat-saturated sequences

Explanation

Lipoma arborescens is characterized by a frond-like synovial mass that follows fat signal on all MRI sequences. It appears hyperintense on T1 and T2 and suppresses completely on fat-saturated (STIR) images.

Question 3191

Topic: 10. Pathology and Oncology

Which of the following is the most definitive surgical management for symptomatic lipoma arborescens of the knee that has failed conservative treatment?

. Arthroscopic or open synovectomy
. Total knee arthroplasty
. Radiation therapy
. Intra-articular steroid injections
. Marginal resection of the patella

Correct Answer & Explanation

. Arthroscopic or open synovectomy

Explanation

The definitive treatment for symptomatic lipoma arborescens is an open or arthroscopic synovectomy. The condition is benign, and recurrence after adequate synovectomy is extremely rare.

Question 3192

Topic: Soft Tissue Tumors & Metastasis

Histologic examination of a specimen retrieved from a patient with lipoma arborescens will classically demonstrate which of the following?

. Atypical lipoblasts with hyperchromatic nuclei
. Replacement of subsynovial tissue by mature adipocytes
. Hemosiderin-laden macrophages and multinucleated giant cells
. Monosodium urate crystals with negative birefringence
. Granulomatous inflammation with caseating necrosis

Correct Answer & Explanation

. Replacement of subsynovial tissue by mature adipocytes

Explanation

Lipoma arborescens is not a true neoplasm but a reactive condition. Histology shows the replacement of the normal subsynovial stroma by mature adipocytes underlying a hypertrophic synovial lining.

Question 3193

Topic: Soft Tissue Tumors & Metastasis

In which anatomic location is lipoma arborescens most frequently identified?

. Subdeltoid bursa of the shoulder
. Olecranon bursa of the elbow
. Volar wrist capsule
. Suprapatellar pouch of the knee
. Retrocalcaneal bursa of the ankle

Correct Answer & Explanation

. Suprapatellar pouch of the knee

Explanation

Lipoma arborescens most commonly affects the knee, particularly the suprapatellar pouch. It frequently presents as a painless, chronic, and boggy effusion.

Question 3194

Topic: 10. Pathology and Oncology

Which of the following underlying conditions is most frequently associated with the development of secondary lipoma arborescens?

. Osteosarcoma
. Degenerative joint disease (Osteoarthritis)
. Ankylosing spondylitis
. Hemophilia
. Lyme disease

Correct Answer & Explanation

. Degenerative joint disease (Osteoarthritis)

Explanation

While lipoma arborescens can be idiopathic, it is most commonly a secondary reactive process associated with underlying chronic synovial irritation, most notably degenerative joint disease (osteoarthritis) or prior trauma.

Question 3195

Topic: 10. Pathology and Oncology

Lipoma arborescens is a rare, benign intra-articular lesion. Which of the following underlying joint conditions is most frequently associated with its development?

. Hemophilia
. Rheumatoid arthritis
. Osteoarthritis
. Pigmented villonodular synovitis
. Gout

Correct Answer & Explanation

. Osteoarthritis

Explanation

Lipoma arborescens is generally considered a reactive process rather than a true neoplasm. It is most commonly associated with chronic joint irritation, particularly secondary to degenerative osteoarthritis.

Question 3196

Topic: Soft Tissue Tumors & Metastasis

A 45-year-old woman presents with recurrent knee effusions. MRI reveals a villous, lipomatous synovial proliferation.

Which MRI sequence change will confirm the diagnosis of lipoma arborescens by extinguishing the high signal of the lesion?

. T2 weighting
. T1 weighting
. Fat-suppressed sequence (e.g., STIR)
. Gradient echo (GRE) sequence
. Contrast-enhanced T1 weighting

Correct Answer & Explanation

. Fat-suppressed sequence (e.g., STIR)

Explanation

The lesion is composed of mature adipose tissue. Therefore, its signal will follow fat on all sequences and will suppress (appear dark) on fat-suppressed sequences like STIR or T1-fat sat.

Question 3197

Topic: Soft Tissue Tumors & Metastasis

Histological examination of a specimen retrieved from a knee synovectomy in a patient with suspected lipoma arborescens will most likely demonstrate which of the following?

. Multinucleated giant cells with hemosiderin deposition
. Atypical lipoblasts with hyperchromatic nuclei
. Replacement of sub-synovial tissue by mature adipocytes
. Granulomas with caseating necrosis
. Monosodium urate crystals surrounded by macrophages

Correct Answer & Explanation

. Replacement of sub-synovial tissue by mature adipocytes

Explanation

Lipoma arborescens is characterized histologically by the diffuse replacement of the sub-synovial connective tissue with mature adipocytes forming villous projections. Hemosiderin deposition would indicate PVNS.

Question 3198

Topic: Soft Tissue Tumors & Metastasis

What is the most common anatomical location for the development of lipoma arborescens?

. Subacromial bursa
. Suprapatellar pouch of the knee
. Olecranon bursa
. Radiocarpal joint
. Ankle joint

Correct Answer & Explanation

. Suprapatellar pouch of the knee

Explanation

Lipoma arborescens most frequently affects the knee, specifically localizing to the suprapatellar pouch. It typically presents as a slow-growing, painless effusion.

Question 3199

Topic: 10. Pathology and Oncology

Which of the following histological findings is pathognomonic for lipoma arborescens?

. Multinucleated giant cells with hemosiderin-laden macrophages
. Replacement of subsynovial tissue by mature adipocytes
. Caseating granulomas within the synovial stroma
. Proliferation of atypical chondrocytes in a myxoid background
. Dense neutrophilic infiltrate with fibrinoid necrosis

Correct Answer & Explanation

. Replacement of subsynovial tissue by mature adipocytes

Explanation

Lipoma arborescens is a rare, benign intra-articular lesion characterized histologically by the villous proliferation of the synovium and the replacement of the subsynovial connective tissue by mature fat cells.

Question 3200

Topic: Soft Tissue Tumors & Metastasis

Lipoma arborescens is most frequently observed in which of the following anatomic locations?

. Subacromial bursa of the shoulder
. Olecranon bursa of the elbow
. Volar tenosynovium of the wrist
. Suprapatellar pouch of the knee
. Retrocalcaneal bursa of the ankle

Correct Answer & Explanation

. Suprapatellar pouch of the knee

Explanation

Lipoma arborescens predominantly affects the knee joint, specifically localizing most often in the suprapatellar pouch. It presents as a painless, boggy swelling of the joint.

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