4. Pigmented lesions Flashcards
What are the 2 categories (/types of causes) of oral pigmentation?
exogenous or endogenous
What are the exogenous causes of oral pigmentation?
- 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
What is black hair tongue?
papillary hyperplasia + overgrowth of pigment-producing bacteria, more common in smokers
How is black hairy tongue managed?
no immediate treatment but good OH including tongue scraping should reduce the appearance
What is an amalgam tattoo?
amalgam introduced into socket/mucosa during treatment
How does an amalgam tattoo present?
symptomless blue/black lesion, may be seen on radiograph
What is the histology of an amalgam tattoo?
- 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
What is the treatment for an amalgam tattoo?
- 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
What are the endogenous causes of oral pigmentation?
- 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
What is pigmented naevi?
developmental lesions with proliferation of melanocytes
What is Peutz-Jeghers syndrome? (presentation)
multiple pigmented lesions on skin/mucosa, lips, tongue, palate, buccal mucosa, intestinal polyposis
What is smoker’s melanosis?
pigmentary incontinence
How can HIV infection cause oral pigmentation?
numerous melanotic macules in some individuals
What are melanotic macules?
- well-defined small flat brown/black lesions
- due to increased activity of melanocytes
- benign
Where are the most common sites of melanotic macules?
buccal mucosa, palate and gingiva
How are melanotic macules treated?
benign but are frequently excised to confirm diagnosis and exclude melanoma
What is the histology of a melanotic macule?
- increased melanin pigment in basal keratinocytes - not increased number of melanocytes
- melanin pigmentary incontinence in underlying connective tissue
What is mucosal melanoma?
- malignant neoplasm of mucosal melanocytes
- primary intraoral mucosal melanoma is rare but can occur
What age range is intraoral mucosal melanoma most common in?
40-60yrs
What are the most common intraoral sites of mucosal melanoma?
hard palate and maxillary gingiva
How does mucosal melanoma present?
- 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
What is the prognosis like for mucosal melanomas?
poor
What is the aetiology of mucosal melanoma?
- aetiology unknown
- biology of mucosal melanomas is different from skin melanomas
What is the histopathology of mucosal melanoma?
- 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
What is this?
an advanced melanoma affecting the right maxillary tubérosité and alveolous
What is the treatment for mucosal melanoma?
- surgical resection is mainstay treatment
- adjuvant radiotherapy
- role of immunotherapy
What is melanotic neuroectodermal tumour of infancy?
very rare, locally aggressive, rapidly growing pigmented mass, mostly in <1yr, M>F
Where does melanotic neuroectodermal tumour of infancy most frequently occur?
anterior maxillary alveolus
What is the cause of melanotic neuroectodermal tumour of infancy?
? neural crest cell origin, pathogenesis is unknown
What is the histopathology of melanotic neuroectodermal tumour of infancy?
tumour comprises 2 cell population - neuroblastic cells and pigmented epithelial cells
What is the treatment for melanotic neuroectodermal tumour of infancy?
- complete local excision is treatment of choice
- tumour of uncertain malignancy potential
- can recur
- small number do metastasise
