10. Pathology and Oncology MCQs

The image demonstrates the gross curettage specimen of a primary bone tumor excised from the posterior elements of a 17-year-old's cervical spine. The tumor typically presents with dull pain that is not completely relieved by NSAIDs. Which of the following best describes the classical radiographic finding of this condition?

A 17-year-old male presents with chronic dull, aching back pain that is not completely relieved by NSAIDs. Imaging shows a 2.5 cm expansile lytic lesion in the posterior elements of L3.

What is the most likely diagnosis?

A biopsy is taken from a painful expansile lesion in the C2 lamina. Histology demonstrates the following features.

Which histologic finding is most characteristic of this condition?

Which of the following radiographic findings is most characteristic of an aggressive osteoblastoma rather than conventional osteosarcoma?

A 10-year-old girl presents with a rapidly enlarging mass over her proximal humerus. Radiographs show an eccentric, expansile, purely lytic lesion. MRI demonstrates multiple fluid-fluid levels. What is the most appropriate definitive surgical management after biopsy confirms an active aneurysmal bone cyst (ABC)?

A 16-year-old male presents with dull, aching pain in his cervical spine. Radiographs and MRI demonstrate an expansile 3.5 cm lesion in the posterior elements of C4.

During curettage, the lesion appears hypervascular and granular. Which of the following best describes the distinguishing features of this lesion compared to an osteoid osteoma?

A biopsy from a diaphyseal femur lesion in an 11-year-old boy reveals sheets of uniform, small, round, blue cells. Molecular testing is positive for a t(11;22)(q24;q12) translocation. Which of the following fusion proteins is most likely driving this malignancy?

A 12-year-old boy with Multiple Hereditary Exostoses (MHE) is evaluated for a rapidly growing, painful lesion on his proximal humerus. Mutations in EXT1 and EXT2 genes are implicated in MHE. These genes normally encode enzymes responsible for the synthesis of which molecule?

A 9-year-old girl sustains a pathologic fracture through a proximal humerus lesion. Radiographs demonstrate a centrally located, lytic metaphyseal lesion with a "fallen leaf" sign. Which of the following best describes the natural history of this lesion if left untreated?

Aneurysmal bone cysts (ABCs) can occur as primary lesions or secondary to other bone tumors. Primary ABCs have been shown to be true neoplasms driven by a specific genetic rearrangement. Which gene is typically upregulated due to translocation in primary ABCs?

A 10-year-old boy undergoes knee radiographs following minor trauma, revealing an incidental, eccentric, cortically based, multiloculated lucent lesion in the distal femoral metaphysis. He is completely asymptomatic. What is the most appropriate management?

A 15-year-old boy complains of chronic knee pain. Radiographs demonstrate a well-circumscribed, eccentrically located, lytic lesion exclusively within the proximal tibial epiphysis. Biopsy reveals mononuclear cells with longitudinal nuclear grooves and areas of "chicken-wire" calcification. What is the diagnosis?

A 4-year-old boy presents with a painful, solitary lytic lesion of the skull. A biopsy demonstrates sheets of cells with indented nuclei intermixed with eosinophils. Immunohistochemistry is positive for CD1a and S-100. Electron microscopy of these cells would most likely show:

A 13-year-old girl is diagnosed with high-grade intramedullary osteosarcoma of the distal femur. Which of the following is considered the most significant adverse prognostic factor at the time of initial diagnosis?

During curettage of a suspected benign spinal lesion in a 20-year-old female, the surgeon notes the gross appearance shown in the provided atlas image.

The tissue is red, granular, and heavily bleeding. Histologic analysis is ordered. Which feature is crucial to differentiate this lesion (osteoblastoma) from a well-differentiated osteosarcoma?

A 16-year-old male presents with localized cervical spine pain. Radiographs reveal a 3.5 cm expansile, radiolucent lesion in the posterior elements of C4.

Which of the following characteristics most reliably differentiates this lesion from an osteoid osteoma?

A 19-year-old female undergoes curettage for an expansile, painful lesion in the posterior elements of T12. The gross pathological specimen is shown.

Histological analysis shows rich vascularity and prominent osteoblasts surrounding irregular osteoid. What is the most common potential complication if this lesion is treated with standard intralesional curettage alone?

A 12-year-old boy presents with multiple painless, bony prominences around his knees, ankles, and shoulders. Radiographs reveal multiple osteochondromas pointing away from the joint lines. He is diagnosed with Multiple Hereditary Exostoses (MHE). Which of the following genes is most likely mutated, and what is the estimated risk of malignant transformation in his lifetime?

An 18-year-old male undergoes curettage of a 3.5 cm posterior spinal lesion. The gross specimen demonstrates hemorrhagic, gritty red tissue.

Based on the gross appearance and size of the lesion, what is the most likely diagnosis?