4. Pigmented lesions

Question 1

What are the 2 categories (/types of causes) of oral pigmentation?

Answer 1

exogenous or endogenous

Question 2

What are the exogenous causes of oral pigmentation?

Answer 2

• superficial staining of mucosa e.g. foods, drinks, tobacco
• black hairy tongue
• foreign bodies e.g. amalgam tattoos
• heavy metal poisoning
• some drugs e.g. NSAIDs, antimalarials, chlorhexidine

Question 3

What is black hair tongue?

Answer 3

papillary hyperplasia + overgrowth of pigment-producing bacteria, more common in smokers

Question 4

How is black hairy tongue managed?

Answer 4

no immediate treatment but good OH including tongue scraping should reduce the appearance

Question 5

What is an amalgam tattoo?

Answer 5

amalgam introduced into socket/mucosa during treatment

Question 6

How does an amalgam tattoo present?

Answer 6

symptomless blue/black lesion, may be seen on radiograph

Question 7

What is the histology of an amalgam tattoo?

Answer 7

• pigment is present as widely dispersed, fine brown/black granules or solid fragments of varying size
• associated with collagen and elastic fibres and basement membranes
• OR may be intracellularly within fibroblasts, endothelial cells, macrophages and occasional foreign-body giant cells

Question 8

What is the treatment for an amalgam tattoo?

Answer 8

• none required
• patient may request removal for aesthetics
• if not seen on radiograph may be excised to confirm diagnosis and exclude other more concerning lesions

Question 9

What are the endogenous causes of oral pigmentation?

Answer 9

• normal variation in pigmentation
• melanotic macule
• pigmented naevi
• Peutz-Jeghers syndrome
• smoker’s melanosis
• HIV infection
• may be a manifestation of systemic disease (Addison’s), malignancy
• mucosal melanoma
• melantoic neuroectodermal tumour of infancy

Question 10

What is pigmented naevi?

Answer 10

developmental lesions with proliferation of melanocytes

Question 11

What is Peutz-Jeghers syndrome? (presentation)

Answer 11

multiple pigmented lesions on skin/mucosa, lips, tongue, palate, buccal mucosa, intestinal polyposis

Question 12

What is smoker’s melanosis?

Answer 12

pigmentary incontinence

Question 13

How can HIV infection cause oral pigmentation?

Answer 13

numerous melanotic macules in some individuals

Question 14

What are melanotic macules?

Answer 14

• well-defined small flat brown/black lesions
• due to increased activity of melanocytes
• benign

Question 15

Where are the most common sites of melanotic macules?

Answer 15

buccal mucosa, palate and gingiva

Question 16

How are melanotic macules treated?

Answer 16

benign but are frequently excised to confirm diagnosis and exclude melanoma

Question 17

What is the histology of a melanotic macule?

Answer 17

• increased melanin pigment in basal keratinocytes - not increased number of melanocytes
• melanin pigmentary incontinence in underlying connective tissue

Question 18

What is mucosal melanoma?

Answer 18

• malignant neoplasm of mucosal melanocytes
• primary intraoral mucosal melanoma is rare but can occur

Question 19

What age range is intraoral mucosal melanoma most common in?

Answer 19

40-60yrs

Question 20

What are the most common intraoral sites of mucosal melanoma?

Answer 20

hard palate and maxillary gingiva

Question 21

How does mucosal melanoma present?

Answer 21

• dark brown or black, or can be non-pigmented and red
• typically asymptomatic at first
• may remain unnoticed until pain, ulceration, bleeding or a neck mass
• regional lymph node and blood-borne metastases are common
• typically very advanced at presentation
• very invasive, metastasise early

Question 22

What is the prognosis like for mucosal melanomas?

Answer 22

poor

Question 23

What is the aetiology of mucosal melanoma?

Answer 23

• aetiology unknown
• biology of mucosal melanomas is different from skin melanomas

Question 24

What is the histopathology of mucosal melanoma?

Answer 24

• melanomas are highly pleomorphic neoplasms, cells appear epithelioid or spindle-shaped
• the amount of melanin pigment is varibale and in some may be absent
• immunohistochemistry using specific markers for malignant melanocytes can be useful in such cases

Question 25

What is this?

Answer 25

an advanced melanoma affecting the right maxillary tubérosité and alveolous

Question 26

What is the treatment for mucosal melanoma?

Answer 26

• surgical resection is mainstay treatment
• adjuvant radiotherapy
• role of immunotherapy

Question 27

What is melanotic neuroectodermal tumour of infancy?

Answer 27

very rare, locally aggressive, rapidly growing pigmented mass, mostly in <1yr, M>F

Question 28

Where does melanotic neuroectodermal tumour of infancy most frequently occur?

Answer 28

anterior maxillary alveolus

Question 29

What is the cause of melanotic neuroectodermal tumour of infancy?

Answer 29

? neural crest cell origin, pathogenesis is unknown

Question 30

What is the histopathology of melanotic neuroectodermal tumour of infancy?

Answer 30

tumour comprises 2 cell population - neuroblastic cells and pigmented epithelial cells

Question 31

What is the treatment for melanotic neuroectodermal tumour of infancy?

Answer 31

• complete local excision is treatment of choice
• tumour of uncertain malignancy potential
• can recur
• small number do metastasise