Disorders of Growth & Cancer 1

Question 1

Developmental Anomalies

1. Definition? [1]
2. Causes? [4]

Answer 1

1. any congenital (present at or before birth) defect that occurs when normal growth & differentiation of the fetus is disturbed which can arise at any stage of embryonic development and vary greatly in type/severity
2. Causes:
   
   • genetic mutations,
   • chromosomal aberrations,
   • teratogens
   • environmental factors (smoking/alcohol)

Question 2

What is the difference between a congenital anomaly and a development anomaly? [2]

Answer 2

1. Congenital anomalies:
   
   • anomalies that exist at or before birth regardless of the cause
2. Developmental anomaly
   
   • deformity, absence or excess body parts/tissues which occur when normal growth is disturbed

Question 3

What are the 2 categories of congenital anomalies? [2]

Answer 3

1. Functional/metabolic
   
   • how the body works
   • (inborn errors of metabolism, haemophilia, cystic fibrosis)
2. Structural
   
   • how the body is made up physically/architecturally

Question 4

Ventricular Septal Defect

1. What is it? [2]
2. Signs & Symptoms? [4]

Answer 4

1. acyanotic congenital heart defect, aka left-to-right shunt
2. signs & symptoms:
   
   • usually symptomless at birth
   • usually manifests a few weeks after birth
   • no signs of cyanosis at early stage
   • uncorrected VSD can increase pulmonary resistance leading to the reversal of the shunt and corresponding cyanosis

Question 5

Spina Bifida

1. Definition? [1]
2. Symptoms? [5]

Answer 5

1. Defect of the neural tube wherein a portion of it fails to develop or close properly
2. Symptoms:
   
   • muscle weakness or paralysis
   • bowel and bladder problems
   • seizures
   • orthopedic problems, such as, deformed feet, uneven hips and scoliosis
   • hydrocephalus

Question 6

Hamartoma

1. Definition? [1]
2. an example of a hamartoma = chondroid hamartoma in the lungs
   
   • How does it present on x-ray? [1]
   • How can it mimic malignancy clinically? [1]
   • What is it composed of? [4]

Answer 6

1. an benign overgrowth of mature tissue in which the elements show disordered arrangement and proportion in comparison to normal
2. Chondroid Hamartoma:
   
   • seen as a ‘coin lesion’ on x-ray
   • can mimic malignancy clinically if endobronchial
   • composed of a mixture of epithelium, cartilage, fat, smooth muscle

Question 7

Ectopia

1. Definition? [1]
2. Describe the following examples of ectopia:
   
   • Ectopic Cordis? [1]
   • Ectopic Thyroid Tissue? [1]
   • Ectopic Pregnancy? [1]

Answer 7

1. An abnormal location or position of an organ or a tissue, most often occurring congenitally but can occur as a result of injury
2. Ectopia cordis:
   
   • displacement of heart outside the body
3. Ectopic thyroid tissue:
   
   • nodules of mature thyroid tissue located elsewhere in the neck
4. Ectopic pregnancy:
   
   • implantation occurring in fallopian tube rather than endometrium
   • (more often seen in the context of pelvic inflammatory disease or previous surgery)

Question 8

Diverticulum

1. Definition? [1]
2. Example: Diverticular Disease
   
   • Effects of diverticular disease? [4]
   • Pathogenesis of diverticular disease? [5]
3. Example: Merkel’s Diverticulum
   
   • What is it? [1]
   • Appearance & composition of MD? [3]
   • Complications of MD? [5]
   • What is intussusception?

Answer 8

1. Circumscribed pouch/sac caused by herniation of lining mucosa of an organ through defect in muscular coat
2. Diverticular Disease
   
   • Effects include
     
     • inflammation
     • bleeding
     • perforation
     • fistulation
   • Pathogenesis
     
     • chronic inflammation and healing → fibrosis → hypertrophy of the muscle → exacerbation of the problem→ stenosis and eventually large bowel obstruction
3. Merkel’s Diverticulum
   
   • blind ending duct that is a remnant of the yolk sac that failed to involute
   • appearance & composition:
     
     • 2 inches long
     • present at the terminal ileum
     • contains all layers of the intestine and often has ectopic tissue within it (pancreatic/gastric)
   • complications:
     
     • inflammation
     • bleeding (from ulcerated gastric tissue)
     • perforation
     • obstruction/intussusception
   • intussusception = the telescoping (invagination) of one part of the bowel into another

Question 9

Cellular Adaptations to Stress

1. Define cell adaptation [1]
2. What is the difference between physiological and pathological adaptations? [2]

Answer 9

1. Adaptations are reversible changes in the number/size/type of cells in response to changes in their environment
2. Physiological adaptations = responses of cells to normal stimulation by hormones or endogenous chemical mediators o
3. Pathological adaptations = responses to stress that allow cells to modulate their structure function and avoid injury

Question 10

Hypertrophy

1. Definition? [1]
2. Examples of physiological hypertrophy? [2]
3. Examples of pathological hypertrophy? [1]
4. Causes? [2]

Answer 10

1. Increase in the size of cells & therefore increase in the size of an organ due to an increased synthesis of structural proteins & organelles, which occurs when cells are incapable of dividing
2. Physiological Hypertrophy:
   
   • increased muscle mass due to exercise
   • enlargement of uterus during pregnancy
3. Pathological Hypertrophy:
   
   • left ventricular hypertrophy/heart failure
4. Causes:
   
   • increased functional demand
   • hormonal stimulation

Question 11

Hyperplasia

1. Definition? [1]
2. Examples of physiological hyperplasia? [2]
3. Examples of pathological hyperplasia? [2]

Answer 11

1. Increase in the number of cells in an organ or tissue
2. Physiological hyperplasia:
   
   • hormonal (normal proliferative endometrium)
   • compensatory: hyperplasia that occurs when a portion of a tissue is removed or diseased
3. Pathological hyperplasia
   
   • caused by excessive hormonal or growth factor stimulation (androgens:BPH, oestrogen: atypical endometrial hyperplasia)

Question 12

Atrophy

1. Definition? [1]
2. Causes of atrophy? [6]

Answer 12

1. Shrinkage in the size numbers of the cell by the loss of cell substance resulting from decreased protein synthesis and increased protein degradation
2. Causes:
   
   • loss of innervation
   • diminished blood supply
   • inadequate nutrition
   • decreased workload
   • loss of endocrine stimulation
   • aging (senile atrophy)

Question 13

Metaplasia

1. Definition? [1]
2. Describe the metaplastic change in:
   
   • trachea & bronchi of cigarette smokers? [2]
   • lower oesophagus in chronic gastric reflux? [2]

Answer 13

1. Reversible change from one fully differentiated cell type into another
2. Metaplastic change in:
   
   • cigarette smokers = normal ciliated columnar epithelial cells of trachea & bronchi are replaced by stratified squamous epithelial cells
   • chronic gastric reflux = normal stratified squamous epithelium of the lower oesophagus may undergo metaplasia to gastric columnar epithelium