Hem n Onc 8-8 (10) Flashcards
This patient presents with a polypoid exophytic mass on the wall of the cecum during a colonoscopy. The growth is positive for mucinous adenocarcinoma. This patient’s neoplasm was found in the cecum, which is located before the ascending colon and after the ileocecal valve.
Superior mesenteric lymph nodes receive lymph drainage from the jejunum, ileum, cecum, the cecal appendix, and the ascending and transverse parts of the colon. Thus, this patient’s neoplasm is most likely?
to spread to the superior mesenteric lymph nodes. To facilitate memorization of this anatomy, the lymph drainage follows the vascular supply of these regions. Embryologically, all foregut derivatives are supplied by the celiac trunk, midgut derivatives by superior mesenteric artery (SMA), and hindgut derivatives by inferior mesenteric artery (IMA). Because the cecum is a midgut derivative, it is supplied by the SMA; therefore, it is drained by the superior mesenteric group of lymph nodes.
It would be unlikely for this patient’s adenocarcinoma to spread first to the following groups of lymph nodes:
Celiac lymph nodes drain lymph fluid from the liver, spleen, pancreas and upper duodenum.
Inferior mesenteric lymph nodes drain lymph fluid from the descending colon, starting at the splenic flexure to the upper rectum and including the sigmoid colon.
Internal iliac lymph nodes drain lymph fluid from the lower rectum to the anal canal (above the pectinate line), bladder, vagina (middle third), cervix, and prostate.
Superficial inguinal lymph nodes drain lymph fluid from ?
the anal canal (below the pectinate line), skin below the umbilicus (except the popliteal area), scrotum, and vulva.
Recent-onset headache and bitemporal hemianopia, in combination with imaging showing a calcified cyst in the suprasellar region, are classic for craniopharyngioma. Craniopharyngioma is the most common supratentorial tumor in children and is derived from remnants of Rathke’s pouch. Rathke’s pouch gives rise to the anterior pituitary gland, and deficiencies of the anterior pituitary hormones, such as growth hormone, are responsible for the symptoms of growth failure, hypothyroidism, and diabetes insipidus often seen in these patients.
As the tumor grows, it compresses the optic chiasm (resulting in bilateral hemianopia) and causes ?
headache. Bilateral hemianopia and headache are also presenting signs of a pituitary adenoma, such as a prolactinoma. In contrast to craniopharyngioma, prolactinomas are associated with increased levels of hormones such as prolactin, leading to hypogonadism and galactorrhea. The table compares the characteristics of craniopharyngiomas versus pituitary adenomas. Be careful not to confuse them!
Patients with craniopharyngioma may also have decreased levels of other anterior pituitary hormones, including thyroid-stimulating hormone and luteinizing hormone; consequently, testosterone and thyroid hormone levels may be decreased, not increased.
Although dopamine inhibits prolactin secretion, the craniopharyngioma impedes delivery of dopamine to the anterior pituitary; therefore, the prolactin level is more likely to be increased in this patient, not decreased.
The release of aldosterone is regulated by ?
the renal-angiotensin-aldosterone system, not the anterior pituitary. Thus, aldosterone is not likely to be affected by the presence of a craniopharyngioma.
The patient is a 65-year-old immigrant from Africa who has been experiencing episodes of hematuria over the past several months. He presented at the emergency department following an episode of gross hematuria.
A physical examination finds mild hepatosplenomegaly, and urinalysis is positive for blood. A CT urogram shows a large filling defect in the bladder, and a beside cystoscopy reveals a large fungating mass is seen adherent to the superior part of the bladder. A biopsy of the mass shows?
keratin pearl formation (indicated by the arrows in this image), a common finding in squamous cell cancers. Squamous cell carcinoma can be distinguished from transitional cell carcinoma pathologically by its appearance.
This patient is suffering from squamous cell carcinoma (SCC) of the bladder. Although this condition is rare in the United States, it is the most common type of bladder cancer in the world, accounting for 95% of cases. The most common cause is chronic irritation by the eggs of the helminth Schistosoma haematobium, which lodge in the bladder wall.
Countries in which Schistosoma haematobium is endemic have much higher rates of SCC of the bladder, and the organism is prevalent in many countries in sub-Saharan Africa.
Cigarette smoking is the most common risk factor for transitional cell carcinoma of the bladder, which is more common the United States than SCC of the bladder. Although cigarette smoking has also been linked to an increased risk of SCC of the bladder, the fact that this patient is originally from Kenya suggests helminth infection is the more likely risk factor.
Aniline dye exposure is also associated with?
transitional cell bladder carcinoma, but is not associated with SCC of the bladder. The association with human papillomavirus infection and bladder cancer remains unclear; this infection is mostly implicated in cervical carcinoma.
Although long-term catheterization can cause irritation that predisposes to squamous cell carcinoma, there is no indication that this patient had an indwelling catheter at any time.
To answer this question, you must understand that microtubule assembly/disassembly is a critical process that occurs during mitosis (M phase of the cell cycle); if this process is blocked, cell division will stop. The vinca alkaloids (vincristine and vinblastine) exert their effect specifically through the inhibition of microtubule function and spindle formation, which are critical to mitosis. In contrast,?
taxanes (paclitaxel and docetaxel) reversibly bind to tubulin and hyperstabilizes microtubules that have already polymerized, preventing spindle breakdown.
The other pairs of drugs listed are not both specific M-phase inhibitors. 5-Flourouracil, 6-mercaptopurine, and methotrexate are specific S-phase inhibitors, whereas bleomycin is a G2-phase inhibitor. Both cyclophosphamide and busulfan are cell cycle nonspecific.
This patient presents with a nodule in the left lobe of her thyroid but has no tremor, restlessness, heat intolerance or increased anxiety. The histologic image provided with the vignette shows a psammoma body, a concentrically calcified lamellated inclusion. The image here shows cells with cleared-out nuclei with no chromatin in the center, known as “Orphan Annie” eyes. These histologic findings are characteristic of papillary carcinoma of the thyroid.
Papillary carcinoma is the most common form of ?
thyroid cancer. A major risk factor for the development of these cancers is a history of ionizing radiation to the neck. These cancers typically appear as cold lesions on a scintiscan.
Follicular and medullary carcinomas of the thyroid, goiter, and thyroglossal duct cysts are not associated with the finding of psammoma bodies on histologic examination. Nontoxic goiter does not result from a neoplastic process. A thyroglossal duct cyst would present as a ?
midline lesion and would not be localized to one lobe.
A 72-year-old Caucasian man undergoes hip surgery. On his third hospital day, he develops chest pain, tachycardia, dyspnea, and a low-grade fever. The man goes into cardiac arrest and efforts to resuscitate him are unsuccessful. On autopsy a massive pulmonary embolus is discovered.
Which of the following would most likely predispose the patient to this event?
Mutation in the factor V gene
A mutation in the factor V gene, also known as factor V Leiden, causes resistance to deactivation of factor V by protein C. Uninhibited factor V activity leads to a hypercoagulable state, which predisposes to deep vein thrombosis (DVT) and subsequent pulmonary embolism (PE). Factor V Leiden mutation is the most common cause of inherited thrombophilia and is most commonly found in Caucasian individuals. However, having a non-Caucasian patient should not exclude factor V Leiden when all other signs point to the disease, as it has been found in people of varying ethnicities. Clinical signs of PE include tachycardia, tachypnea, and low-grade fever, though many patients with PE are asymptomatic.
Factor VIII deficiency (hemophilia A) would predispose an individual to bleeding. Factor VIII is an integral part of the intrinsic coagulation cascade.
High, rather than low, homocysteine levels are associated with a hypercoagulable state. Though the mechanism remains unclear, promotion of thrombotic factors, adhesion molecules, platelet reactivity, and inhibition of fibrinolysis have been implicated.
HomocysteineThrombophiliaAdhesionMoleculePlateletInhibitionFibrinolysis
[ D ] [ 10% ]
Proteins C and S act as negative regulators of the coagulation cascade. Therefore a deficiency, rather than overproduction, will lead to?
a hypercoagulable state.
[ E ] [ 4% ]
von Willebrand factor allows platelets to adhere to a defect where collagen is exposed and binds inactive factor VIII in circulation. A deficiency (von Willebrand disease) leads to bleeding complications such as epistaxis, menorrhagia, and gastrointestinal bleeds.
This patient presented with right foot pain and was found to have a thrombus in her popliteal vein. A positive Homan sign (pain on dorsiflexion on the foot) on physical exam is a classic finding for deep venous thrombosis (DVT). In conjunction with the other findings of malar rash (seen in the vignette image), joint pain, oral ulcers, anemia (decreased hemoglobin), and renal disease (elevated creatinine), this patient likely has undiagnosed systemic lupus erythematosus.
Patients with lupus are at risk of developing acquired antiphospholipid antibody syndrome caused by the lupus anticoagulant. Lupus anticoagulant is an IgM or IgG antibody that binds platelet phospholipids. Platelet phospholipids are required for both the intrinsic and extrinsic clotting pathways. Antiphospholipid antibodies bind to platelet phospholipids, thereby making them accessible to clotting factors and leading to recurrent venous and arterial thrombosis. Because the partial thromboplastin time (PTT) assays use exogenous phospholipids, the antibodies inhibit?
their function and paradoxically show an increase in coagulation time (hence the name lupus anticoagulant). Although antiphospholipid syndrome often manifests with a normal platelet count, this patient has systemic lupus erythematosus, which is often associated with thrombocytopenia. Lupus anticoagulant is also associated with recurrent miscarriage as well as false positive syphilis tests.
Factor VIII antibodies result in increased bleeding (similar to hemophilia A), not increased clotting as seen in this patient, and would cause a prolonged PT and PTT.
Heparin antibodies target heparin but can also cross-react with and destroy platelets; the inactivated heparin results in a hypercoagulable state, with no PT/PTT prolongation.
GpIIb/IIIa antibodies target platelets and lead to?
idiopathic thrombocytopenic purpura (ITP), which is associated with normal a PT/PTT.
RBC antibodies lead to hemolytic anemia, in which signs of increased RBC breakdown such as jaundice and elevated bilirubin may be seen.
This patient presents with microangiopathic hemolytic anemia (MAHA), thrombocytopenia, neurologic and renal abnormalities, and fever, which represent the classic pentad of thrombotic thrombocytopenic purpura (TTP). Patients with TTP have large multimers of von Willebrand factor (vWF) because there is a deficiency of the metalloprotease that breaks down the ultralarge vWF multimers. This metalloprotease is ADAMTS13, and autoantibodies against it can usually be isolated from the plasma of a patient with the acquired form of TTP.
The hallmark findings of TTP are MAHA and thrombocytopenia. The presence of ultralarge vWF multimers leads to?
intravascular platelet aggregation, creating partially thrombosed vessels. As RBCs are forced through this narrowed lumen they are exposed to high shear forces, which leads to intravascular hemolysis and the formation of schistocytes (fragmented RBCs seen in the patient’s blood smear). Thrombocytopenia results from deposition of platelets in microthrombi. Neurologic findings may be seen with TTP, with subtle manifestations such as headaches and confusion being common. Transient focal neurologic findings may be seen, and some patients may have seizures or be comatose. Renal insufficiency is usually mild, and renal failure is rare. TTP should be suspected if MAHA and thrombocytopenia are present.
Levels of other proteins in the answers choices would not be used to diagnose TTP:
Clotting factor levels would be used to diagnose hemophilia A and B, which are deficiencies in factors VIII and IX, respectively.
Cytoskeletal protein deficiencies (ankyrin, spectrin) lead to hereditary spherocytosis (HS).
Pyruvate kinase deficiency is an example of inherited kinase deficiency, leading to?
ATP deficiency in RBCs and, as a consequence, hemolytic anemia.
Shiga toxin hemolytic-uremic syndrome (ST-HUS) stems from a bacterial toxin and is more commonly seen in children. ST-HUS is associated with a prominent gastrointestinal prodrome of abdominal pain, nausea, vomiting, and diarrhea (often bloody). HUS and TTP are both caused by insults that lead to excessive activation of platelets which deposit as thrombi in the microcirculatory beds.
