Pigmented lesions

Question 1

Sources of pigment (4)

Answer 1

Melanin (majority)
Haemosiderin
Amalgam or heavy metals
Chromogenic bacteria

Question 2

Haemosiderin (3)

Answer 2

Breakdown product from RBCs
Iron stored
Brown

Question 3

Melanin (3)

Answer 3

Produced by melanocytes (or nevus cells)
Found in basal third of epithelium
Black/brown

Question 4

How is melanin transferred to adjacent keratinocytes? (2)

Answer 4

Via membrane-bound organelles called melanosomes

Question 5

Amalgam and heavy metals (4)

Answer 5

Heavy metals include lead, bismuth, mercury, silver, arsenic and gold
May directly leach into mucosa from dental restoration and crowns
Deposited due to drugs containing heavy metals e.g. Pepto-bismol
Work or home environment

Question 6

Sources of occupational exposure (2)

Answer 6

Manufacture of: Ammunition, dental x-ray films, plumbing, ceramic glazes.
Jobs: Lead miners, plumbers, mechanics, glass manufacturers, construction workers, welding, processing of ore, production of paints and pigments.

Question 7

Chromogenic bacteria (4)

Answer 7

Bacteria that produce pigment
Aspergillus and Actinomyces
Often seen in hairy tongue
Bacterial enzymes act on iron in saliva

Question 8

Exogenous oral pigmented lesions (4)

Answer 8

Amalgam tattoo
Foreign body tattoo
Heavy metal (occupation or drugs)
Black hairy tongue (bacteria)

Question 9

Developmental endogenous oral pigmented lesions (4)

Answer 9

Physiological (melanin)
Peutz Jehger’s syndrome (melanin)
Haemochromatosis (haemosiderin)
Pigmented naevus (melanin)

Question 10

Acquired endogenous oral pigmented lesions (5)

Answer 10

Addison’s disease (melanin)
Drug induced (melanin)
Post inflammatory (melanin)
Smoker’s melanosis (melanin)
Melanotic macule (melanin)

Question 11

Neoplastic oral pigmented lesions (1)

Answer 11

Melanoma (melanin)

Question 12

Types of endogenous oral pigmented lesions (3)

Answer 12

Developmental
Acquired
Neoplastic

Question 13

Black hairy tongue (4)

Answer 13

Affects posterior dorsal tongue
Decrease in normal desquamation process – associated with soft diet, smoking, antibiotic use
Elongated filiform papillae – can be black, brown, white
Discolouration caused by chromogenic bacteria, chlorhexidine, foods, smoking

Question 14

Peutz-Jeghers (4)

Answer 14

Genetic disorder - autosomal dominant
Pigmented mucocutaneous macules, GI polyps, usually small intestine with normal increased risk of malignant change associated with polyps
Melanotic spots characteristically small and multiple
Very obvious around the lips

Question 15

Histological features of endogenous pigmentation (1)

Answer 15

Increase in amount of melanin

Question 16

Haemochromatosis (6)

Answer 16

Genetic disorder – autosomal recessive
Accelerated rate of intestinal iron absorption
Raised serum ferritin and transferrin saturation
Accumulation of iron (as haemosiderin)
Leads to ‘bronze’ skin pigmentation, liver cirrhosis, diabetes mellitus
Treated with regular venesection

Question 17

What is melanin synthesised by? (3)

Answer 17

Nevus cells which are derived from the neural crest

Found in the skin and mucosa

Question 18

Histological types of nevus (3)

Answer 18

Many
Junctional (epithelium)
Intradermal/ mucosal (CT)
Compound (both)

Question 19

Addison’s disease (5)

Answer 19

Destruction of entire adrenal cortex
Approx. 90% of cases in UK caused by autoimmune disease
Lack of adrenocortical hormone:
= production of adrenocorticotropic hormone (ACTH) by the anterior pituitary gland.
ACTH induces melanocyte-stimulating hormone:
= pigmentation of the skin and oral mucosa
Diffuse brown patches on the buccal mucosa, palate and tongue and gingivae. Extraoral sites – palmar creases, new scars

Question 20

Drugs associated with pigmentation (many)

Answer 20

Antimalarials: quinacrine, chloroquine, hydroxychloroquine
Quinidine
Zidovudine (AZT) 
Tetracycline
Minocycline
Chlorpromazine
Oral contraceptives
Clofazimine
Ketoconazole
Amiodarone
Busulfan
Doxorubicin
Bleomycin
Cyclophosphamide

Question 21

Reasons for pigmentation (1)

Answer 21

Melanin can drop into lamina propria

Question 22

Malignant melanoma (10)

Answer 22

<1% of all oral malignancies
Proliferation of malignant melanocytes along the junction between the epithelial and connective tissues, as well as within the connective tissue
Palate
4th - 7th decade
Men > women
Asymptomatic, slow-growing brown or black patch with asymmetric and irregular borders VS rapidly enlarging mass associated with ulceration, bleeding, pain and bone destruction
Some are non-pigmented (amelanotic)
Aggressive and often fatal disease (worse prognosis than skin lesions)
Treatment: radical surgical excision with clear margins. Radiation and chemotherapy are ineffective, which adds to the difficulties associated with management of this malignancy
Overall 5-year survival rate:15%