USMLE Question No.4: A 57-year-old woman had her last menstrual period at the age of 46 ....

A 57-year-old woman had her last menstrual period at the age of 46. However, for the past 4 months she has experienced intermittent vaginal hemorrhage. A right ovarian mass is identified.Which of the following is the most likely diagnosis?

(A) arrhenoblastoma
(B) Brenner tumor
(C) dysgerminoma
(D) granulosa cell tumor
(E) Sertoli-Leydig cell tumor
(F) teratoma

Answer:
D:

An ovarian mass raises the possibility of a tumor and vaginal hemorrhage in a postmenopausal woman and suggests an estrogenproducing tumor. One of the first estrogenproducing tumors to consider is granulosa cell tumor. Arrhenoblastoma (Sertoli-Leydig cell tumor) (choice A) secretes androgens, not estrogens. Brenner tumor (choice B) is an uncommon ovarian neoplasm without hormonal activity. Dysgerminoma (choice C) is the female counterpart of the male seminoma and does not produce hormones. Sertoli-Leydig cell tumor (choice E) is a synonym for arrhenoblastoma (choice A). Teratoma (choice F) is also hormonally inactive.

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USMLE Question No. 3: A 2-day-old male infant has not passed any meconium and is now developing signs of obstruction ....

A 2-day-old male infant has not passed any meconium and is now developing signs of obstruction. Examination of the colon would reveal which of the following abnormalities?

(A) absence of parasympathetic ganglion cells in the submucosal and myenteric plexus
(B) absence of the nerve fibers that innervate the wall
(C) atrophy of the mucosal lining of the wall
(D) hypertrophy of the muscle coat of the wall
(E) presence of multiple small polyps along the mucosal surface

Answer:
A:

Hirschsprung disease is caused by the congenital absence of parasympathetic ganglion cells in the submucosal and myenteric plexus. This presents clinically soon after birth as an inability to pass stool and abdominal distention. The diagnosis is usually confirmed by a full-thickness colon biopsy showing disorganized, nonmyelinated nerve fibers replacing the missing ganglion cells. In Hirschsprung disease, the ganglion cells, not the nerve fibers (choice B), are missing. Muscular hypertrophy (choice D) and atrophy (choice C) are not specific diagnostic findings with Hirschsprung disease. Mucosal polyp development (choice E)is not associated with Hirschsprung disease.

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USMLE question No 2: A 67-year-old retiree was employed for many years in the plastics industry where he was exposed to vinyl chloride ....

A 67-year-old retiree was employed for many years in the plastics industry where he was exposed to vinyl chloride. This industrial exposure has increased his likelihood of developing which of the following?

(A) focal nodular hyperplasia
(B) hepatic adenoma
(C) hepatic angiosarcoma
(D) hepatic fibroma
(E) hepatocellular carcinoma


Answer:
C:

Environmental exposure to vinyl chloride is associated with the later development of hepatic angiosarcoma. Focal nodular hyperplasia (choice A) and hepatic fibroma (choice D) do not at present have well-defined antecedent environmental exposure histories. Hepatic adenomas (choice B) occur sporadically in the setting of exogenous steroid hormone usage. Hepatocellular carcinoma (choice E) is associated with cirrhosis, chronic viral hepatitis, and aflatoxin exposure.

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USMLE question No. 1: A 67-year-old woman presents with a 4-week history of headaches, facial pain, blurred vision, and intense pain ...

A 67-year-old woman presents with a 4-week history of headaches, facial pain, blurred vision, and intense pain and stiffness in her shoulders and hips. She is diagnosed with a vasculitis, and a biopsy of an affected artery is taken. Histological examination is most likely to reveal which of the following characteristic findings?

(A) concentric “onion skin” thickening and fibrosis
(B) extensive intra- and extravascular granulomatous inflammation
(C) fragmentation of the internal elastic lamina with giant cells
(D) hyaline arteriolosclerosis and luminal narrowing
(E) segmental fibrinoid necrosis and neutrophil infiltration

Answer:
C:
The most likely diagnosis in this case isgiant cell (temporal) arteritis; it is both the most
common systemic vasculitis in this woman’s age group (>60) and is suggested by the clinical
history. Giant cell arteritis may affect any medium- and large-sized arteries, but principally
involves vessels in the head, that is, extracranial branches of the carotid arteries.
Vascular insufficiency leads to symptoms of jaw or facial pain, headaches, and visual
changes, as reported by this patient. In particular, ischemic optic neuropathy may occur
abruptly, resulting in permanent blindness; for this reason, patients with ocular disturbances in
suspected cases demand immediate medical intervention. Temporal arteritis has a strong,
well-known association with polymyalgia rheumatica, a systemic inflammatory disorder
causing symmetrical, often severe muscle pain and stiffness in the shoulders and pelvic girdle
(also reported by this patient); both conditions are associated with the HLA-D4 haplotype.
Microscopically, a section of a vessel affected by giant cell arteritis will demonstrate fragmentation of the internal elastic lamina and the presence of multinucleated giant cells.
Concentric “onion skin” thickening and fibrosis (choice A) may be seen most commonly in
malignant hypertension but also in other conditions such as primary sclerosing cholangitis.
Extensive intra- and extravascular granulomatous inflammation (choice B) refers to
Wegener granulomatosis which often includes:
(i) acute necrotizing granulomas of the upper
and/or lower respiratory tract;
(ii) granulomatous
vasculitis; and
(iii) renal disease.

Hyaline arteriolosclerosis and luminal narrowing (choice C) is found in association with benign hypertension and in diabetes mellitus but is also seen in some normotensive, nondiabetic elderly individuals. Segmental fibrinoid necrosis and neutrophil infiltration (choice E) is a description of the acute phase of polyarteritis nodosa.

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A case study of 62 year old female having atrial fibrillation, MI, and fracture of femur

A 62-year-old woman has had atrial fibrillation since experiencing a myocardial infarction (MI) 7 months prior. Two weeks ago she was hospitalized following a car accident in which she suffered a compound fracture of her left femur and several severe contusions. She now returns to the emergency room with right flank pain, hematuria, and left-sided paralysis. These newly developing problems are most likely the result of which of the following?

(A) air embolism from the compound fracture
(B) bone marrow embolus from the fractured femur
(C) fat embolism from the fractured femur
(D) systemic thromboemboli from the left atrium
(E) venous thromboemboli from the deep leg veins

ANSWER:
D:

Atrial fibrillation produces turbulence that is conducive to the formation of thrombi which can then embolize throughout the systemic circulation. In this patient the right flank pain and hematuria and left-sided paralysis suggest that thromboemboli traveled to the right kidney and the brain, respectively.Embolism of air (choice A) has variable effects, although small amounts are typically inconsequential. Larger volumes (~ >100 mL) can obstruct arteries and lead to ischemia and necrosis; an air embolism that lodges in the right heart may lead to sudden death.However, air embolism is rare and is not the most likely event in this patient. Bone marrow embolism (choice B) can occur following a broken bone or cardiac resuscitation, but typically will have no clinical consequences.However, fat embolism (choice C) from a broken long bone or traumatized areas of adipose tissue can, when severe, produce clinical manifestations.

These follow the trauma by about 1–3 days and usually include dyspnea,skin rash, and acute neurologic changes. In a few cases this has been fatal. Venous thromboemboli from deep leg veins (choice E) could not get past the lungs (with the unusual exception of paradoxical embolism in a person with a septal defect) so could not reach the kidneys or brain to cause the effects reported for this patient.

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