Hem n Onc 8-6 (7) Flashcards Preview

Hematology and Oncology USMLE 1 > Hem n Onc 8-6 (7) > Flashcards

Flashcards in Hem n Onc 8-6 (7) Deck (12):
1

This is a 60-year-old man presenting with persistent headache that has worsened over of the past several months. He also reports worsening erectile dysfunction and mentions that he feels clumsy, having walked into door frames and suffering from a fall leading to a pelvic fracture. He is also having trouble with lateral peripheral vision. The vignette describes a presentation of prolactinoma, the most common tumor of the pituitary gland.
The patient’s signs and symptoms are a consequence of ?

excessive prolactin secretion and local mass effects on suprasellar structures. Among these structures is the optic chiasm, which is situated immediately superior to the pituitary gland. Compression of the optic chiasm by pituitary tumors characteristically causes bitemporal hemianopia, or tunnel vision

2

Prolactinomas cause bitemporal hemianopia due to compression of the optic chiasm. Prolactin hypersecretion due to prolactinoma can cause decreased libido in men and women. Additionally, it can also cause ?

erectile dysfunction and gynecomastia in men, while in women it can cause galactorrhea, amenorrhea, and infertility.

3

If the patient was dropping things with this right hand, it would suggest tumor compression or infiltration into the motor cortex, or precentral gyrus, of the left frontal lobe. However, unilateral muscle weakness is more likely in a transient ischemic attack or stroke of these regions. A tumor of the pituitary gland, such as prolactinoma, generally cannot cause this finding via local compression of surrounding structures.

Furthermore, pituitary masses are more likely to compress the optic chiasm as oppose to other cranial nerves VII and IX/X, which contribute to facial movements and swallowing, respectively. Compression or ischemia of the motor cortex within the frontal lobe, as well as compression or damage to cranial nerve VII (Bell palsy) are more likely to result in right facial droop, than a pituitary tumor would be.

Painful swallowing, or odynophagia, can occur with ?

compression or ischemia of the medulla involving cranial nerves IX and X or the motor cortex within the frontal lobe. It is not likely to be seen as a result of a tumor of the pituitary gland.

Lastly, pituitary masses are not associated with urinary incontinence symptoms. Urinary incontinence, gait ataxia (due to motor and sensory control, not visual disturbances), and dementia are the classic triad associated with normal-pressure hydrocephalus. But this patient does not have any of the symptoms of hydrocephalus.

4

The Centers for Disease Control and Prevention (CDC) reports that a healthcare worker has up to a 10% chance of contracting ?

hepatitis C from a needlestick injury.
An unvaccinated worker exposed to blood by a needlestick injury has up to a 30% chance of contracting hepatitis B. However, the worker in the case above is fully vaccinated and has a much higher degree of protection against hepatitis B infection. With vaccination, the hepatitis B infection risk is almost nonexistent.

5

The Occupational Safety and Health Administration (OSHA) reports that the chance of HIV infection if accidentally stuck with a needle used on an HIV-positive patient is between 0.3% and 0.45%. There is some limited evidence that this risk is lowered with postexposure prophylaxis with zidovudine, although this has not been proven and there have been reports of failure of this prophylaxis.

The risk of infection with hepatitis A or tuberculosis after a needlestick injury is?

quite small, as these pathogens are transmitted by the fecal-oral route or by airborne exposure, respectively.

Your best protection against needlestick injury is to stick to the precautions you’ve been taught. If you do accidentally end up sticking yourself, follow the measures listed below. And next time, please, be more careful!

6

This patient presents with severe hip pain and a pathologic fracture of the pelvis. A biopsy reveals abundant malignant plasma cells, as seen in the photomicrograph, and indicate that this patient is suffering from multiple myeloma. Multiple lytic “punched out” lesions in the skull are classic for this plasma cell malignancy.
Multiple myeloma cells also infiltrate other areas of the skeleton, such as the pelvis, ribs and vertebrae, explaining the patient’s fracture in the absence of overt trauma. The lytic bone lesions (as seen in this x-ray of an upper extremity) are typical of ?

the lytic lesions seen in multiple myeloma. These lytic bone lesions are responsible for this patient’s hypercalcemia in the setting of normal alkaline phosphatase levels.

Proteinuria (termed Bence Jones proteins in this setting) is a common finding in multiple myeloma, because the neoplastic plasma cells secrete an abundance of immunoglobulin proteins, with the light chains readily excreted. Importantly, this proteinuria is typically seen on electrophoresis

7

Focal neurologic deficits, such as unilateral leg weakness, would signify metastasis to the central nervous system. The histologic features of this patient’s biopsy are not consistent with metastatic adenocarcinoma of the prostate, which may present with palpable hard nodule on rectal examination. A palpable parathyroid nodule may be associated with ?

hyperparathyroidism and hypercalcemia, but these would also present with elevated alkaline phosphatase. Lastly, facial muscle contraction on tapping the facial nerve is a manifestation of hypocalcemia.

8

TRAP is a bone turnover marker that under normal circumstances is an embryonic product. High blood levels of TRAP is most characteristic of hairy cell leukemia (HCL), shown in this image. Hairy cell leukemia is a low-grade B-cell neoplasm that typically?

manifests with bone marrow involvement, leading to anemia, thrombocytopenia, and leukopenia. As a result, patients can show symptoms of fatigue, easy bruising, and recurrent infection.

9

Hairy cell leukemia can also cause massive splenomegaly which may present as abdominal fullness or discomfort. TRAP is not positive in other B-cell neoplasms, so it can be useful in the diagnosis of HCL. However, flow cytometry is also a widely used diagnostic test because HCL cells are positive for CD25 and CD11c.

A focal neurologic defect, causing focal weakness, can be caused by?

neuroblastomas. Jaundice would present in instances of increased heme breakdown or hepatobiliary disease, and may be a symptom of hepatocellular carcinoma. Pencil-thin stools are likely in the setting of a mass in the colon or rectum. Enlarging moles are often a symptom of melanoma.

10

This patient presents with severe back pain, pain on urination and frequent urination at night. The crippling back pain is likely the result of lytic bone lesions (indicated with the arrows) present in this patient’s lumbar spine, which can be confirmed with a sagittal CT image. The urinary urgency, nocturia and dysuria in this patient are most likely due to?

a bladder infection. Together, these symptoms and tests suggest multiple myeloma. Patients with myeloma have decreased levels of normal immunoglobulin molecules, which puts them at risk for recurrent infections.
The increased total protein and the increased calcium levels seen in this patient’s lab values are also signs of multiple myeloma. The increased breakdown of bone experienced by patients with multiple myeloma results in increased serum levels of calcium.

11

Multiple myeloma is a neoplastic proliferation of plasma cells, which produce immunoglobulins. The molecule most commonly produced by the plasma cells is immunoglobulin G or IgG. In multiple myeloma, the proliferation of plasma cells results in production of large amounts of IgG that causes increased total protein.

Increased production of albumin, clotting factors, and/or IgM would cause an?

increase in total protein, but they are not increased in multiple myeloma. Dehydration can cause a relative increase in serum protein concentration, but this patient’s presentation is more consistent with multiple myeloma.


12

Multiple myeloma is caused by neoplastic proliferation of monoclonal plasma cells that produce?

large amounts of IgG, resulting in elevated levels of serum proteins.