Practice Set 190 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.
During physical examination, a plexiform neurofibroma is classically described as feeling like which of the following?
. A "bag of worms"
When utilizing immunohistochemistry to differentiate peripheral nerve sheath tumors from other soft tissue masses, which marker is strongly and uniformly positive in schwannomas?
. S-100
Which of the following histological features best distinguishes a neurofibroma from a schwannoma?
. Neurofibromas have scattered nerve fibers intermixed within the tumor
Which of the following factors is considered the most significant poor prognostic indicator in a patient diagnosed with a Malignant Peripheral Nerve Sheath Tumor (MPNST)?
. Association with Neurofibromatosis Type 1 (NF1)
A patient presents with multiple schwannomas without vestibular nerve involvement. Genetic testing for Schwannomatosis is most likely to reveal a mutation in which of the following genes?
. SMARCB1 or LZTR1
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?
. A palpable mass with a positive Tinel sign radiating distally
Which histological description is the classic hallmark of a neurofibroma?
. Wavy spindle cells with "shredded carrot" collagen in a myxoid matrix
On an MRI of the thigh, a well-defined mass is surrounded by a rim of fat at the superior and inferior poles. This "split fat sign" is most indicative of which type of tumor?
. Peripheral nerve sheath tumor
Malignant Peripheral Nerve Sheath Tumors (MPNSTs) most commonly arise from which of the following pre-existing conditions?
. Plexiform neurofibroma
A surgeon successfully enucleates a peripheral nerve tumor, yielding a mass with a thick, distinct capsule. Postoperatively, the patient has no new motor deficits. The tumor was most likely a:
. Schwannoma
The "fascicular sign" on a T2-weighted MRI of a peripheral nerve tumor is best characterized by which of the following?
. Multiple small ring-like structures corresponding to nerve fascicles
While schwannomas are composed almost exclusively of neoplastic Schwann cells, what cell type combination forms the primary neoplastic component of a neurofibroma?
. Schwann cells admixed with fibroblasts
A 45-year-old with NF1 presents with a progressively enlarging, painful mass in the sciatic nerve distribution. Biopsy reveals spindle cells with high mitotic activity, necrosis, and marked pleomorphism. S-100 staining is patchy and weak. What is the most likely diagnosis?
. Malignant peripheral nerve sheath tumor
A 14-year-old male presents with severe mid-thigh pain and a large soft tissue mass. Radiographs show a destructive diaphyseal lesion with an 'onion-skin' periosteal reaction. A biopsy is obtained. Which of the following cytogenetic abnormalities is most characteristically associated with this diagnosis?
. t(11;22)(q24;q12)
A 55-year-old female presents with diffuse bone pain and recurrent nephrolithiasis. Radiographs demonstrate subperiosteal bone resorption of the radial aspect of the middle phalanges and 'brown tumors' in the long bones. Which of the following laboratory profiles is most consistent with her primary diagnosis?
. High calcium, low phosphate, high PTH
During an open reduction and internal fixation of a femur fracture, the anesthesiologist notes a sudden rise in end-tidal CO2, muscle rigidity, and tachycardia. A diagnosis of malignant hyperthermia is suspected. The definitive treatment for this condition acts by which of the following mechanisms?
. Blocking calcium release from the sarcoplasmic reticulum
A 4-year-old child is brought to the orthopedic clinic with a painful, firm soft tissue mass on the posterior neck and back. Examination of the child's feet reveals bilateral short, malformed great toes. Which of the following is the most appropriate next step in management?
. Observation and genetic testing for an ACVR1 mutation
A 25-year-old male sustains a closed femur fracture and undergoes open reduction and internal fixation under general anesthesia. Thirty minutes into the procedure, he develops tachycardia, muscle rigidity, and a rapid rise in end-tidal CO2. His temperature begins to rise rapidly. Which of the following is the mechanism of action of the drug of choice for treating this life-threatening condition?
. Inhibition of ryanodine receptors to prevent calcium release from the sarcoplasmic reticulum
A 68-year-old male presents with deep, boring thigh pain and systemic fatigue. Radiographs demonstrate multiple 'punched-out' lytic lesions in the proximal femur.
Laboratory studies reveal hypercalcemia and a normocytic anemia. If a bone marrow biopsy is performed, it would most likely reveal an abnormal proliferation of cells that normally secrete which of the following?
. Monoclonal immunoglobulins
A 15-year-old male presents with localized mid-thigh pain and night sweats. Radiographs reveal a permeative diaphyseal lesion with an 'onion-skin' periosteal reaction.
Biopsy demonstrates small round blue cells. The most common chromosomal translocation associated with this condition results in the fusion of which genes?
. EWS-FLI1