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10. Pathology and Oncology MCQs

Practice Set 313 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 6241

Topic: 10. Pathology and Oncology

A 25-year-old male with a history of multiple asymmetrical cartilaginous lesions in the phalanges and bluish subcutaneous nodules presents with a rapidly enlarging, painful mass in his right proximal humerus. Biopsy confirms chondrosarcoma. Which of the following is the most likely underlying syndrome, and what is the approximate lifetime risk of malignant transformation of his skeletal lesions?

. Ollier disease; 1 to 5% risk of chondrosarcoma
. Maffucci syndrome; up to 50% risk of chondrosarcoma
. Multiple Hereditary Exostoses; 20% risk of chondrosarcoma
. McCune-Albright syndrome; 10% risk of osteosarcoma
. Trevor disease; 15% risk of chondrosarcoma

Correct Answer & Explanation

. Maffucci syndrome; up to 50% risk of chondrosarcoma

Explanation

Correct Answer: Maffucci syndrome; up to 50% risk of chondrosarcomaThe presence of multiple enchondromas combined with soft tissue hemangiomas (bluish subcutaneous nodules) is pathognomonic for Maffucci syndrome. Both Ollier disease and Maffucci syndrome represent anarchic development of cartilage (enchondromatosis). However, Maffucci syndrome carries a significantly higher risk of malignant transformation compared to Ollier disease. The risk of chondrosarcoma in Maffucci syndrome is frequently cited as being between 30% and 50%, and the overall lifetime risk of any malignancy (including astrocytomas and GI malignancies) approaches 100%. Ollier disease has a lower malignant transformation risk (typically 5-30%). Multiple Hereditary Exostoses carries a 1-5% risk.

Question 6242

Topic: 10. Pathology and Oncology

A biopsy is taken from a lytic, expansile lesion in the proximal femur of a 15-year-old patient. The lesion has a 'ground-glass' appearance on radiographs. Which of the following histological descriptions is the hallmark of this condition?

. Irregular trabeculae of woven bone lacking prominent osteoblastic rimming, set in a bland fibrous stroma
. Nests of cartilage cells with double nuclei surrounded by a heavily calcified matrix
. Multinucleated giant cells interspersed among mononuclear stromal cells with identical nuclei
. Sheets of small round blue cells with scant cytoplasm and positive CD99 staining
. Disorganized lamellar bone with a mosaic pattern of prominent cement lines

Correct Answer & Explanation

. Irregular trabeculae of woven bone lacking prominent osteoblastic rimming, set in a bland fibrous stroma

Explanation

Correct Answer: Irregular trabeculae of woven bone lacking prominent osteoblastic rimming, set in a bland fibrous stromaThe clinical and radiographic description (lytic, expansile, 'ground-glass' appearance) is classic for Fibrous Dysplasia. Histologically, fibrous dysplasia is characterized by irregular, C- or W-shaped trabeculae of immature woven bone (often described as 'Chinese characters') that arise directly from a moderately cellular, bland fibrous stroma. A key distinguishing feature is the absence of prominent osteoblastic rimming around these bony trabeculae, reflecting the anarchic, arrested development of osteoblasts. Option C describes Giant Cell Tumor. Option D describes Ewing Sarcoma. Option E describes Paget disease of bone.

Question 6243

Topic: Bone Tumors

A 7-year-old girl is diagnosed with Ollier disease after presenting with multiple enchondromas predominantly affecting the right side of her body. Which of the following statements regarding the genetics and transmission of her condition is most accurate?

. It is inherited in an autosomal dominant pattern with incomplete penetrance
. It is caused by a germline mutation in the EXT1 gene
. It results from somatic mosaic mutations in the IDH1 or IDH2 genes and is not inherited
. It is an X-linked recessive disorder affecting primarily males
. It is caused by a somatic mutation in the GNAS gene

Correct Answer & Explanation

. It results from somatic mosaic mutations in the IDH1 or IDH2 genes and is not inherited

Explanation

Correct Answer: It results from somatic mosaic mutations in the IDH1 or IDH2 genes and is not inheritedOllier disease (enchondromatosis) is a non-hereditary disorder characterized by the anarchic development of multiple enchondromas, often with a unilateral predominance. It is caused by somatic mosaic mutations in the isocitrate dehydrogenase 1 (IDH1) or IDH2 genes. Because it is a somatic mosaicism occurring post-zygotically, it is not passed from parent to child. GNAS somatic mutations cause Fibrous Dysplasia. EXT1/EXT2 germline mutations cause Multiple Hereditary Exostoses (autosomal dominant).

Question 6244

Topic: Bone Tumors

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 lesion with high T2 signal intensity. Biopsy confirms an intramuscular myxoma. This combination of findings is pathognomonic for which of the following syndromes?

. McCune-Albright syndrome
. Mazabraud syndrome
. Maffucci syndrome
. Jaffe-Campanacci syndrome
. Klippel-Trenaunay syndrome

Correct Answer & Explanation

. Mazabraud syndrome

Explanation

Correct Answer: Mazabraud syndromeMazabraud syndrome is a rare disorder characterized by the association of fibrous dysplasia (usually polyostotic) and one or multiple intramuscular myxomas. The myxomas typically occur in the same anatomic region as the most severely affected bones. McCune-Albright syndrome involves fibrous dysplasia, cafe-au-lait spots, and endocrinopathies. Maffucci syndrome involves enchondromas and hemangiomas. Jaffe-Campanacci syndrome involves multiple non-ossifying fibromas and cafe-au-lait spots.

Question 6245

Topic: 10. Pathology and Oncology

A 22-year-old male with Multiple Hereditary Exostoses (MHE) is being evaluated in the clinic. He has a prominent osteochondroma on his distal medial femur. Which of the following findings is the strongest indication for prophylactic wide surgical excision of the lesion?

. The lesion is sessile rather than pedunculated
. The patient reports a dull ache after running a marathon
. MRI demonstrates a cartilage cap thickness of 2.5 cm
. The lesion points away from the adjacent joint
. The lesion has caused a 1 cm leg length discrepancy

Correct Answer & Explanation

. MRI demonstrates a cartilage cap thickness of 2.5 cm

Explanation

Correct Answer: MRI demonstrates a cartilage cap thickness of 2.5 cmIn adults with osteochondromas, a cartilage cap thickness greater than 1.5 to 2.0 cm on MRI is highly suspicious for malignant transformation to secondary chondrosarcoma. This warrants wide surgical excision. While sessile lesions have a slightly higher risk of malignancy than pedunculated ones, cap thickness is the most reliable imaging indicator. Pain after extreme exertion is likely mechanical; however, new onset of pain at rest or growth of the lesion after skeletal maturity are clinical red flags. Osteochondromas naturally point away from the joint as they grow, which is a normal finding.

Question 6246

Topic: Bone Tumors

A 4-year-old boy presents with an asymmetric, painless swelling on the medial aspect of his right ankle. Radiographs show an irregular, ossified mass arising from the medial epiphysis of the distal tibia. The condition is characterized by an anarchic overgrowth of epiphyseal cartilage. What is the most likely diagnosis?

. Multiple Epiphyseal Dysplasia
. Chondrodysplasia Punctata
. Dysplasia Epiphysealis Hemimelica (Trevor disease)
. Spondyloepiphyseal Dysplasia Tarda
. Ollier disease

Correct Answer & Explanation

. Dysplasia Epiphysealis Hemimelica (Trevor disease)

Explanation

Correct Answer: Dysplasia Epiphysealis Hemimelica (Trevor disease)Dysplasia Epiphysealis Hemimelica, also known as Trevor disease, is a rare developmental disorder characterized by an asymmetric, anarchic overgrowth of cartilage at the epiphysis (essentially an intra-articular osteochondroma). It most commonly affects the medial side of the epiphyses in the lower extremities (ankle or knee) of young children. Multiple Epiphyseal Dysplasia presents with symmetric, delayed, and irregular ossification of multiple epiphyses. Ollier disease involves the metaphyses and diaphyses (enchondromas), not primarily an epiphyseal overgrowth.

Question 6247

Topic: Bone Tumors

A 6-year-old girl is brought to the orthopedic clinic with a limp and a radiographically confirmed fibrous dysplasia lesion in her proximal femur. Physical examination reveals a large cafe-au-lait macule with irregular 'coast of Maine' borders on her trunk. If this patient has McCune-Albright syndrome, which of the following is the most common endocrine abnormality she is likely to experience?

. Hyperthyroidism
. Cushing syndrome
. Precocious puberty
. Acromegaly
. Hyperparathyroidism

Correct Answer & Explanation

. Precocious puberty

Explanation

Correct Answer: Precocious pubertyMcCune-Albright syndrome is defined by the triad of polyostotic fibrous dysplasia, cafe-au-lait macules, and autonomous endocrine hyperfunction. The most common endocrine manifestation, particularly in females, is gonadotropin-independent precocious puberty, caused by autonomous ovarian cyst formation and estrogen production. While hyperthyroidism, Cushing syndrome, and growth hormone excess (leading to acromegaly/gigantism) can also occur due to the underlying GNAS mutation affecting various endocrine glands, precocious puberty is by far the most frequent.

Question 6248

Topic: 10. Pathology and Oncology

A 25-year-old patient with multiple enchondromas and soft tissue hemangiomas presents for routine follow-up. Aside from chondrosarcoma, which of the following malignancies is this patient at the highest risk of developing compared to the general population?

. Osteosarcoma
. Thyroid carcinoma
. Astrocytoma
. Renal cell carcinoma

Correct Answer & Explanation

. Astrocytoma

Explanation

Correct Answer: AstrocytomaThe patient has Maffucci syndrome, characterized by multiple enchondromas and soft tissue hemangiomas. Patients with Maffucci syndrome have a significantly higher risk of malignant transformation (up to 100% in some long-term studies) compared to those with Ollier disease. In addition to secondary chondrosarcoma, they are at a markedly increased risk for visceral and central nervous system malignancies, most notably astrocytomas, as well as gastrointestinal and ovarian malignancies.

Question 6249

Topic: Bone Tumors

A 14-year-old girl with polyostotic fibrous dysplasia presents with a progressive 'shepherd's crook' deformity of the proximal femur. Surgical correction with valgus osteotomy is planned. Which of the following grafting techniques is most appropriate to minimize the risk of graft resorption and recurrence?

. Cancellous autograft
. Cortical allograft
. Demineralized bone matrix (DBM)
. Synthetic hydroxyapatite

Correct Answer & Explanation

. Cortical allograft

Explanation

Correct Answer: Cortical allograftIn the surgical management of fibrous dysplasia, particularly for structural deformities like the shepherd's crook deformity of the proximal femur, cortical allograft is the preferred graft material. Cancellous autograft is rapidly resorbed and replaced by the dysplastic fibrous tissue, leading to a high rate of recurrence. Cortical allografts resist resorption much better and provide the necessary structural support while incorporating slowly.

Question 6250

Topic: Bone Tumors

Which of the following genetic mutations is most strongly associated with the development of Ollier disease?

. EXT1
. GNAS
. IDH1
. LEMD3

Correct Answer & Explanation

. IDH1

Explanation

Correct Answer: IDH1Ollier disease (enchondromatosis) and Maffucci syndrome are associated with somatic mosaic mutations in the isocitrate dehydrogenase 1 (IDH1) or IDH2 genes. These mutations lead to the production of the oncometabolite D-2-hydroxyglutarate, which interferes with normal chondrocyte differentiation. EXT1 is associated with multiple hereditary exostoses, GNAS with fibrous dysplasia, and LEMD3 with osteopoikilosis.

Question 6251

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 6252

Topic: 10. Pathology and Oncology
A 45-year-old woman with known polyostotic fibrous dysplasia presents with a painless, slow-growing soft tissue mass in her right thigh. MRI shows a well-circumscribed intramuscular lesion that is hyperintense on T2-weighted images and hypointense on T1. Biopsy confirms a benign myxoid neoplasm. What is the eponymous name for this specific syndromic association?
. McCune-Albright syndrome
. Mazabraud syndrome
. Maffucci syndrome
. Jaffe-Campanacci syndrome

Correct Answer & Explanation

. Mazabraud syndrome

Explanation

Mazabraud syndrome is a rare disorder characterized by the association of fibrous dysplasia (usually polyostotic) and one or more intramuscular myxomas. The myxomas typically occur in the same anatomical region as the most severely affected bones. McCune-Albright syndrome is fibrous dysplasia with endocrinopathies and café-au-lait spots. Jaffe-Campanacci syndrome is the association of multiple non-ossifying fibromas with café-au-lait spots.

Question 6253

Topic: 10. Pathology and Oncology

In patients with multiple hereditary exostoses (MHE), malignant transformation to secondary chondrosarcoma occurs in approximately 1-5% of cases. Which of the following anatomical locations is the most common site for this malignant transformation?

. Distal femur
. Proximal tibia
. Pelvis
. Distal radius

Correct Answer & Explanation

. Pelvis

Explanation

Correct Answer: PelvisWhile osteochondromas are most numerous around the knee (distal femur and proximal tibia), malignant transformation to secondary chondrosarcoma in patients with MHE most commonly occurs in the flat bones, particularly the pelvis, followed by the proximal femur and scapula. Lesions in these areas should be monitored closely for growth after skeletal maturity, increasing pain, or a cartilage cap thicker than 1.5 to 2 cm.

Question 6254

Topic: Bone Tumors
A 7-year-old girl is diagnosed with McCune-Albright syndrome. In addition to polyostotic fibrous dysplasia and characteristic café-au-lait macules, which of the following is the most common endocrinopathy seen in this condition?
. Hyperparathyroidism
. Precocious puberty
. Diabetes insipidus
. Adrenal insufficiency

Correct Answer & Explanation

. Precocious puberty

Explanation

McCune-Albright syndrome is defined by the triad of polyostotic fibrous dysplasia, café-au-lait spots (typically with irregular 'Coast of Maine' borders), and autonomous endocrine hyperfunction. The most common endocrinopathy, particularly in females, is gonadotropin-independent precocious puberty. Other possible endocrine abnormalities include hyperthyroidism, growth hormone excess (acromegaly/gigantism), and Cushing syndrome.

Question 6255

Topic: Bone Tumors

Which of the following genetic mutations is most commonly shared in the pathogenesis of both Ollier disease and Maffucci syndrome?

. EXT1
. GNAS1
. IDH1
. LEMD3
. COMP

Correct Answer & Explanation

. IDH1

Explanation

Correct Answer: C (IDH1)Ollier disease (multiple enchondromatosis) and Maffucci syndrome (multiple enchondromatosis associated with soft-tissue hemangiomas) are both non-hereditary skeletal dysplasias. Recent genetic studies have identified somatic mosaic mutations in the isocitrate dehydrogenase 1 (IDH1) and IDH2 genes as the primary drivers in both conditions. EXT1 is associated with Multiple Hereditary Exostoses, GNAS1 with Fibrous Dysplasia, LEMD3 with Melorheostosis and Osteopoikilosis, and COMP with Pseudoachondroplasia.

Question 6256

Topic: 10. Pathology and Oncology

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

. Soft tissue chondroma
. Intramuscular myxoma
. Hemangioma
. Liposarcoma
. Neurofibroma

Correct Answer & Explanation

. Intramuscular myxoma

Explanation

Correct Answer: B (Intramuscular myxoma)The association of polyostotic fibrous dysplasia with intramuscular myxomas is known as Mazabraud syndrome. These myxomas are typically benign, painless, and slow-growing. They appear as well-circumscribed masses with high signal intensity on T2-weighted MRI due to their high mucin content. Recognition of this syndrome is important to avoid misdiagnosing the soft tissue mass as a malignant sarcoma.

Question 6257

Topic: Bone Tumors

In patients with Multiple Hereditary Exostoses (MHE), the characteristic forearm deformity is primarily driven by osteochondromas affecting which specific location, leading to the classic tethering effect?

. Proximal radius
. Distal radius
. Proximal ulna
. Distal ulna
. Diaphysis of the radius

Correct Answer & Explanation

. Distal ulna

Explanation

Correct Answer: D (Distal ulna)The classic forearm deformity in Multiple Hereditary Exostoses (MHE) is primarily caused by the disproportionate involvement of the distal ulna. The distal ulna has a smaller cross-sectional area and contributes a larger percentage to the overall longitudinal growth of the ulna compared to the radius. Osteochondromas here cause significant growth retardation of the ulna, leading to relative ulnar shortening, secondary bowing of the radius, ulnar deviation of the carpus, and potential radial head dislocation.

Question 6258

Topic: Bone Tumors

A 12-year-old boy with polyostotic fibrous dysplasia presents with a progressive 'shepherd's crook' deformity of the proximal femur. Surgical correction is planned. Which of the following principles is most critical for the successful long-term stabilization of this deformity?

. Use of non-vascularized cortical strut allografts
. Curettage and packing with cancellous autograft
. Stabilization with a load-sharing intramedullary device
. Stabilization with a rigid laterally based plate and screws
. Wide resection and endoprosthetic reconstruction

Correct Answer & Explanation

. Stabilization with a load-sharing intramedullary device

Explanation

Correct Answer: C (Stabilization with a load-sharing intramedullary device)In fibrous dysplasia, the abnormal bone is structurally weak. Bone grafting (both autograft and allograft) typically fails because the graft is resorbed and replaced by dysplastic host bone. Rigid plate fixation also has a high failure rate due to poor screw purchase in the dysplastic bone and stress shielding. The gold standard for stabilizing a corrected 'shepherd's crook' deformity is the use of load-sharing intramedullary devices (like a cephalomedullary nail), which span the entire length of the abnormal bone and protect it from bending forces.

Question 6259

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 6260

Topic: 10. Pathology and Oncology

A 35-year-old male with a known history of Multiple Hereditary Exostoses (MHE) presents with new-onset pain and enlargement of a previously stable lesion. Which of the following anatomical locations carries the highest risk for malignant transformation of an osteochondroma in this patient population?

. Distal femur
. Proximal tibia
. Pelvis
. Distal radius
. Metatarsals

Correct Answer & Explanation

. Pelvis

Explanation

Correct Answer: C (Pelvis)Patients with Multiple Hereditary Exostoses (MHE) have an increased risk of malignant transformation to secondary chondrosarcoma (estimated at 1-5%). The risk is significantly higher for lesions located in the axial skeleton and proximal appendicular skeleton, specifically the pelvis, scapula, and proximal femur. Lesions in the distal extremities (like the distal radius or metatarsals) have a very low risk of malignant transformation.

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