Menu

10. Pathology and Oncology MCQs

Practice Set 177 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 3521

Topic: Bone Tumors

A 4-year-old boy presents with an asymmetric, painless swelling of the medial aspect of his right ankle and a developing varus deformity. Radiographs show an irregular, stippled ossification mass arising from the medial epiphysis of the distal tibia. What is the most likely diagnosis?

. Multiple epiphyseal dysplasia
. Chondrodysplasia punctata
. Dysplasia epiphysealis hemimelica (Trevor disease)
. Spondyloepiphyseal dysplasia
. 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 anarchic, asymmetric cartilaginous overgrowth of an epiphysis, most commonly affecting the lower extremity (ankle or knee). It behaves histologically like an osteochondroma but arises from the epiphysis rather than the metaphysis. It typically affects only one half of the epiphysis (hemimelica), leading to asymmetric growth, joint deformity (such as varus or valgus), and mechanical symptoms. Multiple epiphyseal dysplasia is bilateral and symmetric. Chondrodysplasia punctata presents with stippled epiphyses systemically in infancy. Ollier disease involves metaphyseal/diaphyseal enchondromas.

Question 3522

Topic: 10. Pathology and Oncology

A routine radiograph of the pelvis and lower extremities in an asymptomatic 20-year-old female reveals multiple, bilateral, parallel linear striations of dense bone in the metaphyses and diaphyses of the long bones. The skull is normal. What is the most likely diagnosis?

. Osteopoikilosis
. Osteopathia striata
. Osteopetrosis
. Melorheostosis
. Pycnodysostosis

Correct Answer & Explanation

. Osteopathia striata

Explanation

Correct Answer: Osteopathia striataOsteopathia striata (Voorhoeve disease) is a benign, asymptomatic sclerosing bone dysplasia characterized radiographically by multiple parallel, linear, dense striations in the metaphyses and diaphyses of long bones, and sometimes a fan-like appearance in the ilium. It represents an anarchic development of bone density but does not typically cause structural weakness or symptoms. Osteopoikilosis presents as multiple small, round or oval sclerotic foci (bone islands) clustered around joints. Melorheostosis presents as flowing cortical hyperostosis. Osteopetrosis and pycnodysostosis present with generalized, diffuse osteosclerosis and are associated with frequent fractures.

Question 3523

Topic: Bone Tumors

A 14-year-old boy with polyostotic fibrous dysplasia presents with a progressive proximal femoral deformity characterized by severe varus angulation (Shepherd's crook deformity) and increasing hip pain. What is the most appropriate surgical management for this specific deformity?

. Curettage and autologous bone grafting
. Curettage and polymethylmethacrylate (PMMA) packing
. Valgus-producing proximal femoral osteotomy stabilized with an intramedullary device
. Valgus-producing proximal femoral osteotomy stabilized with a lateral plate and screws
. Observation and intravenous bisphosphonate therapy

Correct Answer & Explanation

. Valgus-producing proximal femoral osteotomy stabilized with an intramedullary device

Explanation

Correct Answer: Valgus-producing proximal femoral osteotomy stabilized with an intramedullary deviceIn fibrous dysplasia, the bone is replaced by structurally weak fibro-osseous tissue. Autologous bone graft is contraindicated as it will be resorbed and replaced by dysplastic bone. When correcting a Shepherd's crook deformity, intramedullary devices are strongly preferred over plates and screws. Plates have a high failure rate because screws cannot achieve adequate purchase in the dysplastic bone, leading to pull-out and loss of fixation. Intramedullary nails load-share and span the entire length of the lesion, providing superior biomechanical stability.

Question 3524

Topic: Bone Tumors
An asymptomatic 25-year-old female undergoes a pelvic radiograph following a minor fall. The radiograph incidentally shows numerous small, symmetric, well-defined circular sclerotic foci clustered around the periarticular regions of the pelvis and proximal femurs. If this patient has an associated dermatological condition, what is the most likely diagnosis?
. McCune-Albright syndrome
. Maffucci syndrome
. Buschke-Ollendorff syndrome
. Mazabraud syndrome
. Neurofibromatosis type 1

Correct Answer & Explanation

. Buschke-Ollendorff syndrome

Explanation

The radiographic findings describe osteopoikilosis ('spotted bone disease'), an asymptomatic osteosclerotic dysplasia. When osteopoikilosis is associated with disseminated connective tissue nevi (elastomas or collagenomas) of the skin, it is termed Buschke-Ollendorff syndrome. Both isolated osteopoikilosis and Buschke-Ollendorff syndrome are inherited in an autosomal dominant pattern and are linked to mutations in the LEMD3 gene. Mazabraud syndrome is fibrous dysplasia with intramuscular myxomas. McCune-Albright is polyostotic fibrous dysplasia with café-au-lait spots and endocrine abnormalities.

Question 3525

Topic: 10. Pathology and Oncology

A 28-year-old female with a known history of multiple enchondromas and soft tissue hemangiomas presents with a rapidly enlarging, painful mass in her right distal femur. Which of the following statements regarding her underlying condition is most accurate?

. It is inherited in an autosomal dominant fashion with high penetrance.
. The soft tissue hemangiomas typically undergo malignant transformation to angiosarcoma.
. The condition is caused by a germline mutation in the EXT1 gene.
. Patients have a nearly 100% lifetime risk of developing a malignancy, including chondrosarcomas and visceral tumors.
. The enchondromas are typically symmetrically distributed across the axial skeleton.

Correct Answer & Explanation

. Patients have a nearly 100% lifetime risk of developing a malignancy, including chondrosarcomas and visceral tumors.

Explanation

Correct Answer: Patients have a nearly 100% lifetime risk of developing a malignancy, including chondrosarcomas and visceral tumors.The patient has Maffucci syndrome, characterized by multiple enchondromas and soft tissue hemangiomas. Unlike Ollier disease (which has a ~25-30% risk of malignant transformation to chondrosarcoma), Maffucci syndrome carries a much higher, nearly 100% lifetime risk of malignancy. This includes chondrosarcoma as well as various visceral malignancies (e.g., astrocytomas, ovarian tumors, gastrointestinal malignancies). It is a non-hereditary disorder caused by somatic mosaic mutations in IDH1 or IDH2 genes, not EXT1 (which causes Multiple Hereditary Exostoses). The lesions are typically asymmetric.

Question 3526

Topic: Bone Tumors

A 10-year-old boy with multiple hereditary exostoses (MHE) presents with a progressive forearm deformity. Which of the following is the most characteristic pattern of forearm deformity seen in this condition?

. Relative overgrowth of the ulna with radial deviation of the wrist
. Relative shortening of the ulna with bowing of the radius and ulnar deviation of the wrist
. Proximal radioulnar synostosis with fixed pronation
. Volar subluxation of the distal radioulnar joint with dorsal bowing of the radius
. Symmetrical shortening of both the radius and ulna without angular deformity

Correct Answer & Explanation

. Relative shortening of the ulna with bowing of the radius and ulnar deviation of the wrist

Explanation

Correct Answer: Relative shortening of the ulna with bowing of the radius and ulnar deviation of the wristIn Multiple Hereditary Exostoses (MHE), osteochondromas frequently affect the distal forearm. Because the distal ulna contributes a larger percentage to the overall longitudinal growth of the ulna compared to the radius, exostoses here disproportionately tether and stunt ulnar growth. This leads to relative ulnar shortening, secondary bowing of the radius (which continues to grow but is tethered to the short ulna), ulnar deviation of the carpus, and potential dislocation of the radial head (Madelung-like deformity).

Question 3527

Topic: Bone Tumors
A 45-year-old female with a history of polyostotic fibrous dysplasia presents with a painless, slow-growing soft tissue mass in her right thigh. Magnetic resonance imaging (MRI) reveals a well-circumscribed, intramuscular lesion with high signal intensity on T2-weighted images and low signal on T1-weighted images. Biopsy confirms an intramuscular myxoma. What is the eponymous name for this specific association?
. McCune-Albright syndrome
. Jaffe-Campanacci syndrome
. Mazabraud syndrome
. Buschke-Ollendorff syndrome
. Klippel-Trenaunay 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 anatomic region as the most severely affected bones. Jaffe-Campanacci syndrome is the association of multiple non-ossifying fibromas with café-au-lait spots. McCune-Albright syndrome involves fibrous dysplasia, café-au-lait spots, and precocious puberty/endocrine hyperfunction.

Question 3528

Topic: 10. Pathology and Oncology

A 12-year-old girl undergoes radiographic evaluation for a minor knee injury. The radiographs reveal striking, dense longitudinal striations in the metaphyses and diaphyses of the distal femur and proximal tibia. She has a history of macrocephaly and cleft palate. Which of the following is the most likely inheritance pattern and associated gene mutation for her condition?

. Autosomal dominant, LEMD3
. X-linked dominant, WTX (AMER1)
. Autosomal recessive, TCIRG1
. Somatic mosaicism, GNAS
. Autosomal dominant, COL1A1

Correct Answer & Explanation

. X-linked dominant, WTX (AMER1)

Explanation

Correct Answer: X-linked dominant, WTX (AMER1)The clinical picture describes Osteopathia Striata with Cranial Sclerosis (OSCS). The hallmark radiographic finding is linear longitudinal striations in the long bones. When associated with cranial sclerosis, macrocephaly, and facial dysmorphism (like cleft palate), it is an X-linked dominant condition caused by mutations in the WTX gene (also known as AMER1). It is often lethal in males, hence predominantly seen in females. LEMD3 is associated with osteopoikilosis and melorheostosis. TCIRG1 is associated with infantile malignant osteopetrosis.

Question 3529

Topic: 10. Pathology and Oncology

A 30-year-old male with multiple hereditary exostoses (MHE) presents with a new onset of pain and rapid enlargement of a previously stable osteochondroma on his proximal humerus. Which of the following imaging findings is most highly suspicious for malignant transformation to secondary chondrosarcoma?

. A cartilage cap thickness of 1.0 cm on MRI
. Presence of heavily calcified matrix within the stalk of the lesion
. A cartilage cap thickness greater than 2.0 cm on MRI in an adult
. Continuity of the medullary cavity of the lesion with the host bone
. Growth of the lesion directed away from the adjacent joint

Correct Answer & Explanation

. A cartilage cap thickness greater than 2.0 cm on MRI in an adult

Explanation

Correct Answer: A cartilage cap thickness greater than 2.0 cm on MRI in an adultMalignant transformation of an osteochondroma to a secondary chondrosarcoma occurs in approximately 1-5% of patients with MHE. Clinical signs include new-onset pain or growth after skeletal maturity. On MRI, the most reliable indicator of malignant transformation is a thickened cartilage cap. In adults, a cartilage cap thicker than 1.5 to 2.0 cm is highly suspicious for chondrosarcoma. Continuity of the medullary cavity and growth directed away from the joint are normal, diagnostic features of a benign osteochondroma.

Question 3530

Topic: 10. Pathology and Oncology

A 7-year-old boy is diagnosed with Ollier disease. Which of the following statements best describes the typical clinical and radiographic presentation of this anarchic bone development disorder?

. Symmetrical, bilateral involvement of the axial skeleton with sparing of the appendicular skeleton
. Multiple enchondromas with a predominantly unilateral or asymmetric distribution, often causing limb length discrepancy
. Generalized osteopenia with multiple cortical pseudofractures
. Multiple osteochondromas pointing away from the joints, leading to joint contractures
. Dense, flowing hyperostosis along one side of a long bone cortex

Correct Answer & Explanation

. Multiple enchondromas with a predominantly unilateral or asymmetric distribution, often causing limb length discrepancy

Explanation

Correct Answer: Multiple enchondromas with a predominantly unilateral or asymmetric distribution, often causing limb length discrepancyOllier disease (enchondromatosis) is characterized by the presence of multiple enchondromas (benign cartilage tumors within the medullary cavity). A hallmark of the disease is its asymmetric or predominantly unilateral distribution. The anarchic cartilaginous rests in the metaphyses and diaphyses disrupt normal endochondral ossification, frequently leading to bowing deformities and significant limb length discrepancies. Multiple osteochondromas describe MHE. Flowing hyperostosis describes melorheostosis.

Question 3531

Topic: Bone Tumors
A 12-year-old girl presents with a 'shepherd's crook' deformity of the proximal femur, café-au-lait spots with irregular 'coast of Maine' borders, and a history of precocious puberty. Which of the following best describes the underlying cellular pathophysiology of her skeletal lesions?
. Defective osteoclastic bone resorption due to a TCIRG1 mutation.
. Constitutive activation of adenylate cyclase leading to elevated intracellular cAMP.
. Mutation in the EXT1 gene leading to defective heparan sulfate synthesis.
. Defective type I collagen synthesis due to a COL1A1 mutation.
. Gain-of-function mutation in FGFR3 inhibiting chondrocyte proliferation.

Correct Answer & Explanation

. Constitutive activation of adenylate cyclase leading to elevated intracellular cAMP.

Explanation

This patient presents with the classic triad of McCune-Albright syndrome: polyostotic fibrous dysplasia, café-au-lait spots with irregular borders, and endocrine abnormalities (most commonly precocious puberty). The underlying cause is a post-zygotic somatic activating mutation in the GNAS1 gene. This mutation leads to constitutive activation of the Gs-alpha protein, which in turn causes continuous activation of adenylate cyclase and elevated levels of intracellular cyclic AMP (cAMP). This disrupts normal osteoblast differentiation, leading to the formation of immature woven bone and fibrous tissue characteristic of fibrous dysplasia.

Question 3532

Topic: 10. Pathology and Oncology

A 25-year-old male with a known history of diaphyseal aclasis (multiple hereditary exostoses) presents with a rapidly enlarging, painful mass over his right proximal femur. Which of the following factors is most strongly associated with malignant transformation in this condition?

. Lesions located in the distal appendicular skeleton (hands and feet).
. A cartilage cap thickness of less than 1 cm on MRI.
. Lesions located in the pelvis, shoulder girdle, or proximal femur.
. Presence of a concurrent GNAS1 mutation.
. The presence of sessile rather than pedunculated lesions.

Correct Answer & Explanation

. Lesions located in the pelvis, shoulder girdle, or proximal femur.

Explanation

Correct Answer: Lesions located in the pelvis, shoulder girdle, or proximal femur.Multiple Hereditary Exostoses (MHE) carries a risk of malignant transformation to secondary chondrosarcoma, estimated at 1% to 5%. The risk is significantly higher for lesions located in the axial skeleton and proximal appendicular skeleton (pelvis, scapula, proximal femur, and proximal humerus) compared to distal lesions. A cartilage cap thickness greater than 1.5 to 2 cm in an adult on MRI is highly suspicious for malignant transformation. Sessile versus pedunculated morphology does not inherently dictate malignant potential as strongly as location and cap thickness.

Question 3533

Topic: 10. Pathology and Oncology

A 14-year-old boy is evaluated for multiple asymmetric cartilaginous lesions in the metaphyses and diaphyses of his long bones, predominantly affecting the right side of his body. Physical examination reveals multiple soft tissue hemangiomas with phleboliths visible on radiographs. Which of the following genes is most commonly mutated in this specific syndrome?

. EXT1
. GNAS
. NF1
. IDH1 or IDH2
. PTPN11

Correct Answer & Explanation

. IDH1 or IDH2

Explanation

Correct Answer: IDH1 or IDH2The clinical presentation of multiple enchondromas associated with soft tissue hemangiomas is diagnostic of Maffucci syndrome. Both Ollier disease (multiple enchondromatosis without hemangiomas) and Maffucci syndrome are non-hereditary disorders caused by somatic mosaic mutations in the isocitrate dehydrogenase 1 (IDH1) or IDH2 genes. These mutations lead to the accumulation of the oncometabolite D-2-hydroxyglutarate, which alters DNA methylation and cellular differentiation. Maffucci syndrome carries a very high risk of malignant transformation (both chondrosarcomas and non-skeletal malignancies).

Question 3534

Topic: Bone Tumors

A 22-year-old female with polyostotic fibrous dysplasia presents with progressive hip pain and a severe 'shepherd's crook' deformity of the proximal femur. She has an impending subtrochanteric fracture. Which of the following surgical constructs is most appropriate for stabilizing this lesion after corrective osteotomy?

. Cancellous bone grafting and dynamic hip screw (DHS) fixation.
. Cortical strut allografting and isolated screw fixation.
. External fixation to allow gradual deformity correction.
. Curettage, polymethylmethacrylate (PMMA) packing, and a laterally based plate.
. Valgus producing osteotomy stabilized with an intramedullary nail.

Correct Answer & Explanation

. Valgus producing osteotomy stabilized with an intramedullary nail.

Explanation

Correct Answer: Valgus producing osteotomy stabilized with an intramedullary nail.In fibrous dysplasia, the bone is structurally weak and prone to progressive deformity and fracture. The 'shepherd's crook' deformity requires a valgus-producing osteotomy to restore mechanical alignment. Fixation must span the entire length of the diseased bone to prevent stress risers and subsequent fractures. Intramedullary nailing is the gold standard because it provides load-sharing biomechanics along the entire diaphysis. Plates and screws (load-bearing) have a high failure rate due to poor screw purchase in dysplastic bone. Bone grafting (especially cancellous) is generally ineffective as the graft is rapidly resorbed and replaced by dysplastic fibrous tissue.

Question 3535

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. Magnetic resonance imaging (MRI) reveals a well-circumscribed, intramuscular lesion that is hyperintense on T2-weighted images and hypointense on T1-weighted images. Biopsy confirms a benign, hypocellular, mucoid neoplasm. This clinical presentation is characteristic of which of the following syndromes?
. McCune-Albright syndrome
. Maffucci syndrome
. Jaffe-Campanacci syndrome
. Mazabraud syndrome
. Klippel-Trenaunay 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 are benign soft tissue tumors that typically present as painless masses in the vicinity of the bone lesions, most commonly in the thigh. McCune-Albright syndrome involves fibrous dysplasia, café-au-lait spots, and endocrinopathies. Maffucci syndrome involves enchondromas and hemangiomas. Jaffe-Campanacci syndrome involves multiple non-ossifying fibromas and café-au-lait spots.

Question 3536

Topic: 10. Pathology and Oncology

A 45-year-old female with a known history of polyostotic fibrous dysplasia presents with a painless, slow-growing soft tissue mass deep in her right thigh. Magnetic Resonance Imaging (MRI) reveals a well-circumscribed intramuscular lesion demonstrating high signal intensity on T2-weighted images and low signal on T1-weighted images. What is the most likely diagnosis of this soft tissue mass?

. Intramuscular lipoma
. Intramuscular myxoma
. Soft tissue sarcoma
. Neurofibroma
. Desmoid tumor

Correct Answer & Explanation

. Intramuscular myxoma

Explanation

Correct Answer: Intramuscular myxomaThe association of polyostotic fibrous dysplasia with single or multiple intramuscular myxomas is known as Mazabraud syndrome. These myxomas are benign, slow-growing soft tissue tumors that typically present in adulthood, often decades after the diagnosis of fibrous dysplasia. They characteristically show high T2 signal on MRI due to their high mucin content. Recognition of this syndrome is crucial to avoid misdiagnosing the soft tissue mass as a malignancy.

Question 3537

Topic: 10. Pathology and Oncology
Which of the following clinical features distinguishes Maffucci syndrome from Ollier disease and is associated with a significantly higher lifetime risk of malignant transformation?
. Unilateral distribution of enchondromas
. Presence of soft tissue hemangiomas
. Autosomal dominant inheritance pattern
. Mutation in the EXT1 gene
. Presence of café-au-lait spots

Correct Answer & Explanation

. Presence of soft tissue hemangiomas

Explanation

Both Ollier disease and Maffucci syndrome are non-hereditary disorders characterized by multiple enchondromas (enchondromatosis), which represent an anarchic development of cartilage within the bone marrow cavity. Maffucci syndrome is distinguished from Ollier disease by the concurrent presence of soft tissue hemangiomas (often presenting as bluish subcutaneous nodules with phleboliths). Patients with Maffucci syndrome have a much higher risk of malignant transformation (up to 100% lifetime risk of various malignancies, including chondrosarcoma, astrocytoma, and GI malignancies) compared to Ollier disease (approximately 25-30% risk of chondrosarcoma).

Question 3538

Topic: 10. Pathology and Oncology

Multiple hereditary exostoses (osteochondromatosis) is characterized by the anarchic development of cartilage-capped bone tumors. The underlying genetic mutations in the EXT1 or EXT2 genes primarily result in the defective synthesis of which of the following extracellular matrix components?

. Type I collagen
. Heparan sulfate
. Fibroblast growth factor receptor 3 (FGFR3)
. Cartilage oligomeric matrix protein (COMP)
. Runx2 transcription factor

Correct Answer & Explanation

. Heparan sulfate

Explanation

Correct Answer: Heparan sulfateMultiple hereditary exostoses (MHE) is an autosomal dominant disorder caused by mutations in the EXT1 or EXT2 genes. These genes encode glycosyltransferases involved in the synthesis of heparan sulfate. The deficiency of heparan sulfate disrupts the normal diffusion of Indian hedgehog (Ihh) protein at the growth plate, leading to anarchic proliferation of chondrocytes and the formation of osteochondromas.

Question 3539

Topic: Bone Tumors
A 6-year-old girl presents with a limp and a leg-length discrepancy. Radiographs reveal a 'shepherd's crook' deformity of the proximal femur with a ground-glass appearance in the medullary canal. Physical examination notes large, irregular hyperpigmented macules with jagged borders ('Coast of Maine'). Which of the following endocrine abnormalities is most commonly associated with this patient's syndrome?
. Hypothyroidism
. Precocious puberty
. Hyperparathyroidism
. Diabetes insipidus
. Adrenal insufficiency

Correct Answer & Explanation

. Precocious puberty

Explanation

The patient's presentation of polyostotic fibrous dysplasia (shepherd's crook deformity, ground-glass bone lesions) and café-au-lait spots with irregular borders ('Coast of Maine') is diagnostic of McCune-Albright syndrome. This syndrome is caused by a post-zygotic somatic activating mutation in the GNAS gene, leading to overproduction of cAMP. The most common endocrine manifestation of McCune-Albright syndrome is peripheral precocious puberty, particularly in females, due to autonomous ovarian estrogen production.

Question 3540

Topic: 10. Pathology and Oncology

A 22-year-old male presents with progressive, spontaneous resorption of the clavicle and scapula following a minor trauma. Biopsy of the affected area reveals replacement of normal bone by non-neoplastic, thin-walled vascular and lymphatic channels without evidence of cellular atypia. Which of the following is the most likely diagnosis?

. Paget's disease of bone
. Gorham-Stout disease
. Langerhans cell histiocytosis
. Aneurysmal bone cyst
. Osteofibrous dysplasia

Correct Answer & Explanation

. Gorham-Stout disease

Explanation

Correct Answer: Gorham-Stout diseaseGorham-Stout disease, also known as massive osteolysis or 'vanishing bone disease', is a rare condition characterized by the spontaneous, progressive resorption of bone. It is caused by an anarchic, non-neoplastic proliferation of thin-walled vascular and lymphatic channels within the bone, which stimulates aggressive osteoclastic resorption. It frequently involves the shoulder girdle, skull, or pelvis and can be triggered by minor trauma.

Test Yourself

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

On this Page