Clinical Guide to Oral Diseases. Crispian Scully
melanin production in summer, but this did not cause any dryness, desquamation, or lip atrophy as seen in actinic cheilitis. Fixed drug reaction requires drug uptake, but this is easily ruled out as the patient was not under any medication.
Q2 Which histological feature is/are pathognomonic of a melanocytic macule?
1 Increased size of melanocytes
2 Increased number of melanocytes
3 Elastosis
4 Hemosiderin deposition among epithelial layers
5 Atrophic mucosa
Answers:
1 No
2 Melanocytic macula is characterized by increased melanin production due to the increased number of melanocytes within the dermal–epidermal junction.
3 No
4 No
5 No
Comments: Chronic exposure of the labial mucosa to the sun can cause a great number of alterations ranging from innocent lesions as a result of increased melanin production (melanocytic macules) to those of intermediate risk due to any possible alteration in the epithelium atrophy and underlying submucosa (elastosis as seen in actinic cheilitis), or more severe effects threatening the patient's life (carcinomas) or melanomas. Haemosiderin deposition is irrelevant to solar radiation and strictly related to excess iron deposition within the body tissues.
Q3 What is the difference between café au lait lesions and melanotic macules?
1 Association with genetic disorders
2 Color
3 Presence of giant cell melanocytes in histological sections
4 Onset
5 Risk of malignant transformation
Answers:
1 Numerous café au lait lesions are associated with genetic disorders (i.e. neurofibromatosis 1) while melanotic macules are not.
2 No
3 Both lesions are characterized by increased melanin production but only café au lait lesions show giant cell melanocytes in microscopic examination.
4 Café au lait lesions are related to genetic disorders and appear from birth or childhood while melanotic macules can make their appearance at any age.
5 No
Comments: Both pigmented lesions clinically appear as brown to black discolorations with no tendency of malignancy.
Case 3.6
CO: A 68‐year‐old woman presented with a diffuse skin discoloration on her neck.
HPC: This discoloration appeared two weeks ago, coming after an erythema on the sun‐exposed skin of her neck and was associated with dryness and mild pruritus.
PMH: This lady suffered from a mild rheumatoid arthritis which had being controlled with sulfasalazine and ibuprofen tablets. However, the latter seemed to cause her mild hypertension and therefore, it had been recently replaced with paracetamol. Her medical records revealed a meningioma which was removed five years ago along with a squamous cell carcinoma on her tongue, and ipsilateral lymph nodes, which were also removed two months ago. Additionally, the patient had undergone a course of chemo‐ and radiotherapy which had just been completed on the examination day. She has no other serious skin, hormone, or allergy problems and was an ex‐smoker but not a drinker.
OE: Clinical examination revealed a diffuse brown discoloration on her neck extending from the area below the mandible to the suprasternal notch. The pigmentation is darker in the middle of the neck, near the surgical incision, but fades away at the periphery (Figure 3.6); it is currently associated with mild pruritus caused by her skin dryness.
Q1 What is the possible cause of her neck pigmentation?
1 Melasma
2 Drug‐induced pigmentation
3 Solar pigmentation
4 Addison's disease
5 Radiation‐induced pigmentation
Answers:
1 No
2 No
3 No
4 No
5 The radiotherapy for head and neck cancers creates severe side effects, among them an hyper pigmentation as it seems to activate rather than to destroy melanocytes as obviously seen in this woman's facial and neck skin. This pigmentation begins as a dispersed erythema which finally, within the next one or two weeks, changes to a brown pigmentation that persists for up to four weeks after the end of the therapy.
Comments: The skin pigmentation, caused by solar rays, is not only restricted to the area of irradiation, but affects all parts of the body which are exposed to sun. Addison's disease pigmentation is seen as isolated or diffused pigmentation in the whole body, including the mouth, in contrast to melasma which is mainly restricted to the face. Hyper‐pigmentation is a phototoxic effect of various drugs, including sulfasalazine, but this was not the case here as the pigmentation only appeared during radiotherapy.
Q2 Which of the skin alterations below is/are not side effects of radiotherapy?
1 Edema
2 Desquamation
3 Ulceration
4 Rosacea
5 Skin tags
Answers:
1 No
2 No
3 No
4 Rosacea is a chronic skin disease, unrelated to irradiation and characterized by facial erythema, papules, pustules and swellings and dilation of superficial blood vessels.
5 Mucosal tags are benign growths on the skin of the neck, chest, underneath the breasts and surrounding groin. These lesions have been connected with a number of conditions such as Crohn's disease, polycystic ovary syndrome, acromegaly, and diabetes mellitus type 2, but not with radiation.
Comments: Among the side effects of radiation, erythema and edema are common and usually appear after the first two weeks of treatment, while ulcerations and atrophy are observed at the end of radiotherapy.
Q3 Which of the chemotherapeutic agents below cause increased facial pigmentation?
1 5‐fluorouracil
2 Cyclophosphamide
3 Dasatinib (tyrosine kinase inhibitor)
4 Melphalan
5 Bleomycin
Answers:
1 5‐Fluorouracil is widely used against carcinomas of the skin, oral mucosa, esophagus, stomach, pancreas, breast, and cervix by blocking the action of thymidylate synthase and DNA synthesis and stimulates the production of melanin.
2 Cyclophosphamide is used as a chemotherapeutic agent for lymphoma multiple myelomas, ovarian and breast carcinomas, sarcomas as well as neuroblastomas, as an alkylating agent which blocks DNA and RNA synthesis but increases pigmentation.
3 No
4 Melphalan