Principles of neoplasia

Pathological terms

• Atrophy
• Reduction in organ size due to a reduction in size of individual cells
• Occurs in immobility or nutritional deficiency
• Hyperplasia
• An increase in organ size due to cell proliferation
• Occurs with breast enlargement during pregnancy
• Hypertrophy
• An increase in organ size due to increase in size of individual cells
• Occurs with ventricular hypertrophy due to aortic stenosis
• Metaplasia
• A change from one differentiated cell type to another
• Occurs with bronchial squamous metaplasia in response to smoking
• Barrett's esophagus is also a metaplastic process
• Dysplasia
• Disordered cellular development
• Often pre-malignant
• Examples include cervical intra-epithelial neoplasia

Tumor markers

• The ideal tumor marker would
• Be present in the blood
• Be undetectable in health
• Be produced only by malignant tissue
• Be organ specific
• Would have circulating levels proportional to tumor mass
• The ideal does not exist
• Tumor markers can be used for
• Screening for primary disease
• Diagnosis of primary disease
• Monitoring response to treatment
• Establishing prognosis
• Detection of recurrence

Specific tumor markers

• CA-125 - ovary
• CEA - colon, pancreas, stomach
• PSA - prostate
• Alpha-fetoprotein - teratoma, hepatoma
• Beta-hCG - seminoma, choriocarcinoma
• CA19.9 - pancreas
• CA15.3 - breast
• CA 27.29 - breast

Bibliography

Labdenne P, Heikinheimo M. Clinical use of tumor markers in childhood malignancies. Ann Med 2002; 34: 316-323.
Lamerz R. Role of tumour markers and cytogenetics. Ann Oncol 1999; 10 (Suppl 4): S145-149
McDermott U, Longley D B, Johnston P G. Molecular and biochemical markers in colorectal cancer. Ann Oncol 2002; 13 (Suppl4): S235-245.
Rhodes J M. Usefulness of novel tumor markers. Ann Oncol 1999; 10 (Suppl 4): S118-121

Skin loss - flaps and grafts

Definitions

• Autograft = graft from one part of body to another in the same individual
• Allograft = graft from one individual to another in the same species
• Xenograft = graft from one species to another

Skin grafts

• A skin graft is an autograft
• Can be partial or full thickness depending on the amount of dermis taken

Partial-thickness skin grafts

• Contains epidermis and superficial part of dermis
• Usually taken from donor site with dermatome or Humby knife
• Donor site epithelium grows back from sweat glands and hair follicles
• Graft can be 'meshed' to increase the area that can be covered
• Excess skin can be stored in fridge and reused for up to 3 weeks
• Partial-thickness grafts can not be used on infected wounds
• Not suitable for covering bone, tendon or cartilage
• Cosmetic result is often not good

-- An advancement flap --

Random pattern grafts

• Receives blood supply from segmental anastomotic or axial artery
• Examples include advancement and rotation flaps

--A rotation flap--

Axial pattern grafts

• Receives blood supply from a direct cutaneous arteries
• Examples include:
• Iliofemoral island flap supplied by superficial circumflex iliac artery
• Lateral forehead flap supplied superficial temporal artery
• Deltopectoral island flap supplied by perforating branches of internal mammary artery
• Survival of all flaps depends on it receiving an adequate blood supply
• Depend on length of flap in relationship to its base
• Blood supply can be improved by the use of 'delaying' techniques
• The flap is partially raised and replaced prior to use
• Encourages the flap to increase its blood supply through the pedicle

Tube pedicle grafts

• Frequently raised from abdomen or inner arm
• Parallel skin incisions allow tube of skin to be formed
• Skin defect is then closed
• The length of the tube should not be greater than twice the base
• Long axis of tube should parallel the direction of the cutaneous blood vessels
• Good means of delaying tissue transfer over a long distance
• Produces a good cosmetic result

Myocutaneous flaps

• In most parts of the body the skin receives its blood supply from the underlying muscle
• Muscle, fascia and overlying skin can therefore be moved as one unit
• The survives on major blood vessel supplying the muscle
• Examples include
• Latissimus dorsi flap supplied by thoracodorsal artery
• Transverse rectus abdominis supplied by superior epigastric artery
• Allow tissue transfer to poorly vascularised areas
• Bone can also be transferred for osseous reconstruction
• Flaps usually have no sensation

Free myocutaneous flaps

• Microvascular techniques allow the anastomosis of arteries and veins
• Myocutaneous flaps can therefore be detached from blood supply
• Can be transferred to other parts of body
• Examples include the free transverse rectus abdominis flap

Tissue expansion

• Skin can be gradually stretched to accommodate a greater area
• If skin loss is anticipated it is possible to expand adjacent skin prior to operation
• Tissue expanders can be placed subcutaneously in collapsed state
• Over several weeks can be inflated with saline through a subcutaneous port
• Expanded skin can be used to cover defect and tissue expander removed

Bibliography
Valencia I C, Falabella A F, Eaglstein W H. Skin grafting. Dermatol Clin 2000; 18: 521-532.

Burns

Pathophysiology

• Burn = Coagulative destruction of the skin or mucous membrane
• Caused by heat, chemical or irradiation
• Thermal damage occurs above 48 ºC
• Extent of necrosis is related to temperature and duration of contact
• Burns can result in:
• Increased capillary permeability and fluid loss
• Hypovolaemia and shock
• Increased plasma viscosity and microthrombosis formation
• Haemoglobinuria and renal damage
• Increased metabolic rate and energy metabolism

Assessment

• Initial assessment should be by ATLS principles
• Good early management is required to prevent morbidity or mortality

Airway

• Look for signs of inhalation injury
• Facial burns, soot in nostrils or sputum

Breathing

• Be aware of carbon monoxide poisoning
• Patient may appear 'pink' with a normal pulse oximeter reading

Circulation

• The fluid loss from a burn is significant
• It can result in hypovolaemic shock and acute renal failure

Assessment of extent
Body surface area (BSA) involved can be estimated from

• Lund & Browder chart
• Wallace rule of nine
  

Area	% BSA
Head	9
Each upper limb	9
Each lower limb	18
Front of trunk	18
Back of trunk	18
Perineum	1

Palm of hand approximates to 1% BSA

Burn depth Ability of skin to repair depends on depth of burn Burns can be classified as: Superficial burns Partial thickness burns Full-thickness burns Superficial burns Needs to be differentiated from erythema Epidermis and papillae only are involved Results in red serum0filled blisters Skin blanches on pressure Burn is painful and sensitive Healing occurs in 10 days with no scarring