1
A patient presents to a physician because of troubling "heartburn" and difficulty swallowing. Esophageal
motility studies demonstrate a near absence of smooth muscle peristalsis and lower esophageal
sphincter tone. No mass lesions are noted and the esophagus is not dilated. Which of the
following findings would most likely also be present?
A. Anemia
B. Atrophic glossitis
C. Hourglass-shaped stomach on barium swallow
D. Massively dilated colon
E. Thick skin
Explanation:
The correct answer is E. Near complete absence of muscle tone and peristalsis is characteristic
of involvement of the esophagus with scleroderma, which causes replacement of muscle by dense
connective tissue. Similar changes in the dermis cause the skin to be thickened. The thickened,
shiny skin of the hands may cause them to resemble claws.
Anemia (choice A) and atrophic glossitis (choice B) are associated with esophageal webs in
Plummer-Vinson syndrome.
An hourglass-shaped stomach within the thoracic cavity (choice C) is a feature of a sliding
hiatal hernia.
A massively dilated esophagus (megaesophagus) can be caused by Chagas' disease, a trypanosomal
disease that can also cause massive dilation of the colon (choice D).
A strict vegetarian is not getting sufficient vitamin D in his diet, and he develops osteomalacia. This
disease is characterized by which of the following changes in his bones?
A. Decreased osteoblasts
B. Increased osteoclast activity
C. Increased osteoid
D. Marrow fibrosis
E. Sparse bony trabeculae
Explanation:
The correct answer is C. The hallmark of osteomalacia is widened osteoid seams. Although the
trabeculae are normal in number and size, they do not mineralize effectively, and the rim of
uncalcified osteoid is much larger than normal.
Osteoclast activity is normal in osteomalacia. Increased osteoclast activity (choice B) is
typical of hyperparathyroidism and Paget's disease of bone.
There are increased numbers of osteoblasts in osteomalacia (compare to choice A), which lay
down increased quantities of osteoid in an effort to strengthen the bone. Unfortunately, the
increased osteoid is not mineralized and the bone remains soft and weak.
The bone marrow space is normal in osteomalacia. Marrow fibrosis (choice D) is more typical of
hematopoietic disorders, although hyperparathyroidism may also lead to bone marrow fibrosis.
Although poorly mineralized, the bony trabeculae are of normal abundance in osteomalacia.
Sparse trabeculae (choice E) is characteristic of osteoporosis.
A 35-year-old woman notices a change in the appearance of a mole on her neck. Physical examination
reveals that the lesion is an irregular, nodular, superficial mass with a variegated
appearance. Biopsy demonstrates a primary malignant tumor. Which of the following factors is
most predictive of the patient's long term prognosis?
A. Circumference of lesion
B. Darkness of lesion
C. Degree of color variation
D. Depth of lesion
E. Sharpness of border between lesion and adjacent skin
Explanation:
The correct answer is D. The lesion is a malignant melanoma. Melanomas can develop either de
novo or in an existing mole. Sunlight exposure is a significant risk factor and fair-skinned
persons are at increased risk of developing melanoma. The most significant factor for long term
prognosis is the depth of the lesion, since the superficial dermis lies about 1 mm under the
skin surface, and penetration to this depth is associated with a much higher incidence of
metastasis than is seen with a more superficial location.
The circumference of the lesion (choice A) is much less important than depth, since one form of
melanoma (superficial spreading) can still have good prognosis despite large size, if it has
not extended to the depth of the superficial dermal lymphatic bed.
The darkness (choice B) or degree of variation in color (choice C) do not have prognostic
significance once melanoma is diagnosed.
Irregularity, or fuzziness at the border (choice E) of a mole-like lesion is a good clue to
potential malignancy, but does not affect prognosis once a melanoma is diagnosed.
A 45-year-old man presents to a physician with flank pain and hypertension. Serum chemistries
demonstrate slightly increased blood urea nitrogen and creatinine. Hematuria is noted on
urinalysis. Ultrasound studies demonstrate markedly enlarged kidneys with irregular margins and
many fluid-filled spaces of varying sizes. Excessive secretion of which of the following
hormones would most likely account for the patient's hypertension?
A. ACTH
B. Cortisol
C. Parathormone
D. Renin
E. Thyroxine
Explanation:
The correct answer is D. The disease is adult polycystic kidney disease, which is an autosomal
dominant condition that typically manifests in middle age. While the kidneys appear very badly
deformed, they function surprisingly well because the cystic spaces actually only affect 10% or
less of the nephrons. Pressure exerted by the cysts can somewhat compromise blood flow to some
glomeruli, which is probably why hypertension, as a consequence of renin secretion, is such a
problem for these patients.
ACTH (choice A) can stimulate cortisol (choice B) secretion, and the cortisol (in high amounts)
can have enough mineralocorticoid activity to cause hypertension. However, this would be more
likely with a pituitary tumor, adrenal tumor, or with exogenous corticosteroid use.
Parathormone (choice C) regulates calcium metabolism and does not usually affect blood
pressure.
Thyroxine excess (choice E) can cause hypertension as a consequence of its effects on the heart
and vasculature; this might be seen in the setting of hyperthyroidism due to thyroid disease.
A 45-year-old woman with a history of thyroid disease presents to her physician with a anterior neck
mass. Biopsy demonstrates non-Hodgkin's lymphoma. Which of the following thyroid conditions
most likely preceded the development of lymphoma in this patient?
A. Follicular thyroid carcinoma
B. Graves disease
C. Hashimoto's thyroiditis
D. Nodular goiter
E. Papillary thyroid carcinoma
Explanation:
The correct answer is C. Hashimoto's disease (autoimmune thyroiditis) confers a 60- to-80 fold
increased risk of developing thyroid lymphoma compared to normal controls. This increased risk
is not surprising, considering the histology exhibited in Hashimoto's, in which sheets of
benign but activated lymphocytes infiltrate and eventually destroy the thyroid gland, producing
eventual thyroid failure.
Neither follicular (choice A) nor papillary (choice E) thyroid carcinomas predispose for
lymphoma.
Lymphoma is not particularly related to Graves disease (choice B) or benign nodular goiter
(choice D).
A patient with intestinal malabsorption is found to markedly improve when flour products (bread,
noodles, etc.) are removed from his diet. At the height of the patient's disease, marked
histologic changes would be seen at which of the following sites?
A. Distal large bowel
B. Distal small bowel
C. Entire large bowel
D. Entire small bowel
E. Proximal small bowel
Explanation:
The correct answer is E. The patient has celiac disease, which is apparently an acquired
hypersensitivity to the gluten (such as gliadin) in wheat. Unlike tropical sprue (which may be
related to enterotoxigenic E. coli infection), which involves the entire small bowel, celiac
sprue is usually limited to the proximal small bowel. This may occur because the gluten
antigens have not yet been digested at this point in their journey through the bowel. A gluten-
free diet usually restores the small bowel mucosa.
Accumulation of which of the following substances indicates aging at a cellular level?
A. Beta-carotene
B. Bilirubin
C. Hemosiderin
D. Lipofuscin
E. Melanin
Explanation:
The correct answer is D. Lipofuscin is a brown pigment that accumulates with aging. It is
believed to be produced from the peroxidation of lipids. Lipofuscin accumulation does not
necessarily impair the ability of the cell to function, and can be found in the hearts and
livers of healthy elderly patients.
Beta-carotene (choice A) is a carotenoid ingested in the diet (found in yellow vegetables such
as squash, pumpkins, and carrots) and converted to vitamin A. Excessive beta-carotene can cause
a benign yellow-orange discoloration of the skin in a condition known as carotenemia.
Bilirubin (choice B) is a pigment derived from the metabolism of the heme group of hemoglobin.
As hemoglobin is broken down, it first forms biliverdin, which is subsequently converted to
bilirubin. Bilirubin can be conjugated (to glucuronide) or unconjugated. The conjugated form
(also called the direct reacting portion) accumulates in biliary obstructions. The unconjugated
form of bilirubin (indirect-reacting) accumulates in hemolytic processes.
Hemosiderin (choice C) is the storage form of iron and stains blue with Prussian blue.
Hemosiderin accumulation from breakdown of red cells is seen in chronic passive congestion of
the lung (inside hemosiderin-laden macrophages called "heart failure cells"). Hemosiderin
deposition is also seen in hemochromatosis, a disorder characterized by abnormal iron storage.
Hemochromatosis is seen in patients with increased iron uptake from the GI tract, and in
patients receiving repeated blood transfusion therapy.
Melanin (choice E) is a brown-black pigment made by melanocytes in the skin. Melanin is also
found in the iris, giving the eye its color. Neuromelanin is a type of melanin found in
catecholamine neurons in the brain.
A 25-year-old man presents to a physician because of multiple small nodules on his lips. The clinician
notes that the patient has a marfanoid habitus. Biopsy of one of these nodules demonstrates a
mucosal neuroma. Which of the following screening tests is indicated?
A. Pentagastrin-stimulated calcitonin
B. Serum gastrin
C. Serum insulin
D. Serum parathyroid hormone
E. Serum vasoactive intestinal peptide
Explanation:
The correct answer is A. The presence of mucosal neuromas, particularly when multiple and when
the patient has a marfanoid syndrome, is a marker for multiple endocrine neoplasia type IIb (MEN
IIb). MEN IIb predisposes for medullary carcinoma of the thyroid and pheochromocytoma.
Pentagastrin-stimulated calcitonin studies may suggest the presence of thyroid C cell
hyperplasia, which may precede frank medullary carcinoma.
High serum gastrin (choice B) suggests pancreatic or duodenal gastrinomas, which may be a
component of MEN I.
High serum insulin (choice C) or vasoactive intestinal peptide (choice E) also suggest
pancreatic endocrine tumors, which may be a component of MEN I.
Parathyroid hyperplasia or adenomas with parathyroid hormone secretion (choice D) can be seen in
MEN I and MEN IIa, but are not part of MEN IIb.
An adult patient presents with persistent headaches. A CT scan of the head demonstrates a 2-cm spherical
mass at the junction of the white and gray matter of the lateral aspect of the cerebral
hemisphere. Which of the following would most likely produce this lesion?
A. Astrocytoma
B. Ependymoma
C. Glioblastoma multiforme
D. Meningioma
E. Metastatic carcinoma
Explanation:
The correct answer is E. 70% of adult brain tumors occur above the tentorium (70% of childhood
tumors occur below the tentorium). Statistically, metastases > astrocytomas (including
glioblastoma) > meningioma > pituitary tumor. Location at the junction of cortical gray and
white matter is also typical for metastatic disease, as is the round shape.
Astrocytomas (choice A) typically arise in the white matter and have an irregular shape.
Ependymomas (choice B) are uncommon and arise from the ependymal lining of the ventricles.
Glioblastoma multiforme (choice C) is an aggressive form of astrocytoma that can cause a
"butterfly lesion", crossing between the cerebral hemispheres.
Meningiomas (choice D) can cause spherical lesions, and are usually located on the surface of
the brain.
A 62-year-old female is evaluated for uterine bleeding. In the course of her workup, an endometrial
biopsy reveals marked endometrial hyperplasia. A left ovarian mass is identified, which appears
to be solid and about 4 cm in diameter on ultrasound. The ovarian tumor is most likely to be
a(n)
A. corpus albicans
B. endometrioid carcinoma
C. endometriotic cyst
D. granulosa cell tumor
E. teratoma
Explanation:
The correct answer is D. Granulosa cell tumors arise from the granulosa cells of the ovarian
follicle. Typically occurring in postmenopausal women, granulosa cell tumors are solid, yellow
masses that frequently produce estrogens. Consequently, granulosa cell tumors often present
with abnormal uterine bleeding, and they are considered a risk factor for endometrial
carcinoma.
Corpora albicantia (choice A) are the fibrotic remnants of corpora lutea. The corpus albicans
is small, usually less than 1 cm, and does not produce an ovarian mass or hormonal changes that
might cause bleeding.
Endometrioid carcinoma (choice B) of the ovary is an epithelial malignancy that resembles
endometrial carcinoma by light microscopy. It is a solid and/or cystic tumor that arises (like
serous or mucinous carcinoma) in the absence of any appreciable hormonal imbalance.
An endometriotic cyst (choice C) is a focus of endometriosis within an organ other than the
uterus. Endometriotic cysts are commonly called "chocolate" cysts due to the appearance of
brown, semi-solid hemorrhage with the lining wall of endometrial glands and stroma.
Endometriotic cysts do not appear solid, and they commonly regress after menopause.
Teratomas (choice E) usually appear solid and cystic on diagnostic studies, due to the multiple
tissue components present within. Most teratomas contain hair and sebaceous material among
other things, but they do not produce estrogens. There are rare cases of teratomas containing
predominantly thyroid tissue or carcinoids that may be hormonally active.
A 79-year-old man complains of pain in the upper portion of his neck on swallowing. He occasionally
regurgitates undigested food shortly after eating. Which of the following is the most likely
etiology of his problems?
A. Mallory-Weiss tears
B. Plummer-Vinson syndrome
C. Schatzki rings
D. Traction diverticula
E. Zenker's diverticulum
Explanation:
The correct answer is E. This is the classic presentation of Zenker's diverticulum, which is a
false diverticulum formed by herniation of the mucosa at a point of weakness at the junction of
the pharynx and esophagus in the posterior hypopharyngeal wall. Zenker's diverticulum is also
associated with halitosis, and if the diverticulum fills completely with food, it can cause
dysphagia or obstruction of the esophagus.
Mallory-Weiss tears (choice A) are mucosal tears at the gastroesophageal junction secondary to
repeated, forceful vomiting. They are often seen in alcoholics.
Plummer-Vinson syndrome (choice B) is the triad of dysphagia (due to esophageal webs in the
upper esophagus), atrophic glossitis, and iron-deficiency anemia.
Schatzki rings (choice C) are mucosal rings found in the distal esophagus at the squamocolumnar
junction.
In contrast to a Zenker's diverticulum, the usually asymptomatic traction diverticula (choice
D) are true diverticula involving all of the layers of the esophagus. They are typically caused
by adherence of the esophagus to a scarred mediastinal structure.
A 72-year-old woman complains of constipation and abdominal pain. Over a period of 48 hours, her
symptoms worsen, and she is transported to the hospital for laparoscopic evaluation of an acute
abdomen. At laparoscopy, a volvulus is noted. Which of the following is the most likely
location for the volvulus?
A. Appendix and cecum
B. Ascending colon
C. Descending colon
D. Sigmoid colon
E. Transverse colon
Explanation:
The correct answer is D. Typically, an elderly patient with a volvulus develops an "acute
abdomen", and is found at laparoscopy or laparotomy to have a twisted (and potentially
infarcted) segment of bowel, usually in the poorly supported sigmoid colon. Most other parts of
the colon are held in place by the posterior peritoneal membrane, and the transverse colon is
stretched so that it can not twist. In contrast, intussusception tends to occur either in