Pigmented lesions

Question 1

List 4 things that would cause variation to the colour of natural mucosa

Answer 1

• The presence or absence of keratin
• Quantity and location of blood vessels
• Adipocytes
• Melanin pigmentation

Question 2

Define a pigmented lesion and list the classifications of pigmented lesions

Answer 2

• Definition: any area of altered colouration of the oral mucosa due to the deposition of endogenous or exogenous pigments or foreign material in the tissues
• Endogenous and exogenous, and focal vs diffuse

Question 3

List some causes of melanosis

Answer 3

• Skin: most commonly related to increased sun exposure
• Intraorally: physiologic or idiopathic sources, neoplasia, medication use, high serum concentrations of ACTH hormone, post-inflammatory changes, genetic or autoimmune disease
• If the cause of the pigmentation cannot be clinically ascertained, a tissue biopsy is warranted for definitive diagnosis

Question 4

Describe endogenous pigmented lesions

Answer 4

• Melanin is produced by melanocytes. It is synthesised within melanosomes
• Eumelanin (brown-black) and phenomelanin (red-yellow)
• ‘Melanosis’ is the overproduction of melanin

Question 5

Describe freckle/ ephelis in terms of

• causes
• appearance
• management

Answer 5

Causes
• Endogenous focal
• Seen on sun-exposed regions of the facial or perioral skin and commonly observed in light-skinned individuals
• Caused by increase in melanin production without an increase in the number of melanocytes

Appearance
• Commonly occurring, asymptomatic, small, well-circumscribed brown-coloured macule
• Developmental in origin

Management: no therapeutic intervention required

Question 6

Describe oral/ labial melanotic macules in terms of

• Aetiology
• Clinical features (5)
• Pathology (2)
• Ddx (4)

Answer 6

Aaetiology:
· possibly trauma, sun exposure is not a precipitating factor

Clinical features:
· >females
· Lower lip or intraorally
· Any mucosal site may be affected –primarily on gingiva, buccal mucosa and soft palate
· Presentation in adulthood
· Small, well-circumscribed, uniformly pigmented

Pathology:
· Abundant melanin pigment in the basal cell layer without an increase in the number of melanocytes
· Labial and Oral melanotic macules are identical

Differential diagnoses:
· Melanocytic nevus
· Malignant melanoma
· Amalgam tattoo
· Focal ecchymosis

Question 7

Describe oral melanoacanthoma and how it appears

Answer 7

· Occurs on skin and oral mucosa
· Dark lesion that often arises rapidly
· Mimics melanoma
· Biopsy to establish diagnosis
· Spontaneous resolution may be seen following biopsy
· Reactive in nature
· Histopathology: dendritic-shaped pigmented melanocytes

Question 8

Describe melanocytic nevus

Answer 8

· A benign, exophytic, usually pigmented, congenital lesion of the skin or mucosa composed of focal collections of rounded melanocytes (naevus cells)
· Lesional nevus cells are distinct from the melanocytes that colonise the basal cell layer
· Nevogenesis, genetic and environmental factors
· Congenital or acquired

Question 9

List the 3 types of melanocytic nevus

Answer 9

· Intradermal (mucosal)
· Junctional
· Compound

Question 10

Describe the clinical features of melanocytic nevus

Answer 10

· Rare
· Typically present as solitary lesions
· More common in females
· No distinguishing clinical characteristics
· Asymptomatic, small (<1cm), solitary, brown or blue, well-circumscribed nodule or macule
· Up to 15% may not exhibit evidence of clinical pigmentation
· Common sites, hard palate, buccal and labial mucosae and gingiva
· Most identified in patients over 30y.o.a

Question 11

Describe the stages of nevus formation and explain blue nevus

Answer 11

· Junctional nevus: Nevus cells are confined to the basal layer, at the junction of the epithelium and basement membrane. Junctional nevus appear flat and tan brown.

· Compound nevus: Melanocytes begin to proliferate down to the connective tissue. The mole now has a dome shaped appearance

· Intramucosal nevi: With further maturation of the lesion, nevus cells lose association with the epithelial layer and become confined to the submucosal tissue

· Blue nevus: melanocytes reside deep in the connective tissue and overlying blood vessels dampen the colour of melanin, leading to a blue tint

Question 12

For malignant melanoma, list:

• The 4 risk factors
• Clinical features in terms of appearance/ location/ sequalae
• Pathology
• Diagnosis
• Management

Answer 12

Risk factors:
· Multiple episodes of acute sun exposure
· Immunosuppression
· Presence of multiple cutaneous nevi
· Family history of melanoma –germline mutations to tumor suppressor gene

Clinical features:
· No distinctive clinical appearance
· Any mucosal site may be affected-palate most common site, followed by maxillary gingiva/alveolar crest
· Macular, plaque-like or mass-forming; well circumscribed or irregular, focal or diffuse areas of brown, blue, black
· May be non-specific signs and symptoms: ulceration, pain, tooth mobility, root resorption, bone loss, paresthesia
· Poor prognosis 5 year survival rates of 15%-40%/ 10-year survival 0%, palate worst prognosis, regional lymph metastasis frequent

Pathology
· Radial or vertical pattern of growth
· Radial (superficial) pattern seen in macular lesions
· Pleomorphic melanocytes with nuclear atypia and hyperchromatism within the basal cell region
· Neoplastic cells can invade the overlying epithelium and superficial submucosa

Diagnosis:
· Distinguish between primary neoplasm and metastasis from distant site

Management:
· Primary lesions
· ablative surgery with wide margins, ? adjunctive radiotherapy
· Immunotherapy

Question 13

List the 4 types of melanomas

Answer 13

· Superficial spreading melanoma
· Lentigo malignamelanoma
· Acral lentiginous melanoma
· Nodular melanoma

Question 14

Describe physiological pigmentation in terms of how they appear

Answer 14

· Most common diffuse oral mucosal pigmentation
· Patchy to generalized hyperpigmentation of the oral mucosal tissues. More common in those with dark-skinned complexion
· Pigmentation can be restricted to the gingiva, but melanosis or other mucosal surfaces is not uncommon
· Typically observed in childhood
· Onset of diffuse pigmentation in adulthood - consider pathology

Question 15

Describe drug induced melanosis

Answer 15

· Medications can induce varying degrees of melanosis
· Diffuse yet localized to one mucosal surface, or can involve multiple surfaces
· Pathology: basilar hyperpigmentation and melanin incontinence without in increase in the number of melanocytes
· Smokers melanosis

Question 16

Describe post- inflammatory/ inflammatory hyperpigmentation

Answer 16

· Oral pigmentation has been described in patients with lichen planus due to basilar hyperpigmentation and melanin incontinence
· Upon resolution, pigmentation subsides

Question 17

List 6 pigmentation associated with systemic or genetic disease

Answer 17

· Hypoadrenocorticism (Adrenal Insufficiency or Addison’s Disease)
· Hyperthyroidism (Graves’ Disease)
· Primary Biliary Cirrhosis
· Cushing’s Syndrome/ Cushing’s Disease
· Vitamin B12 Deficiency 
· HIV-AIDS-Associated Melanosis

Question 18

Briefly describe exogenous pigmented lesions

Answer 18

Localised implantation of dental materials (usually amalgam) during:
· Restorative procedures
· As a consequence of extraction
· Cultural reasons-impregnation of carbon particles into the mucosal connective tissue

Question 19

Describe amalgam tattoos

Answer 19

· Most common pigmented lesion in the oral mucosa
· Iatrogenic in origin
· Typically small, asymptomatic, macular, bluish-gray or black
· Any mucosal surface
· Found in the vicinity of teeth with large amalgams, apical region of endodontically treated teeth
· Pathology:•Fine brown granular stippling of collagen fibres
· Little or no inflammation
· Diagnosis: Take a radiograph
· Innocuous-removal is not necessary

Question 20

Describe hairy tongue

Answer 20

· Aetiology unknown. Discolouration of dorsal tongue
· Children rarely affected
· Elongation of filiform papillae, becomes pigmented by colonization of bacteria, foods, drinks and smoking
· Biopsy not required
· Tx: oral hygiene and limit ingestion of colour-forming food and drinks

Question 21

Describe haemoglobin and iron associated pigmentation (ecchymosis)

Answer 21

· Traumatic ecchymosis uncommon in oral mucosa
· Erythrocyte extravasation (accidental infiltration) into the connective tissue
· Bright red to brown discolouration
· Multiple lesions - consider coagulation disorder

Question 22

Describe haemoglobin and iron associated pigmentation (petechiae)

Answer 22

· Capillary haemorrages
· Red / brown
· Petechiae characterised as pinpoint; Purpura 2-4mm
· Consider trauma, viral or systemic disease