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Oral Melanotic Macule vs Melanoma — MFDS Part 1 MCQ

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HardOral MedicineOral Melanotic Macule vs MelanomaMFDS Part 1

A 58-year-old patient has an asymptomatic, solitary 8 mm irregular brown macule on the posterior hard palate. Its duration is uncertain, and there is no adjacent restoration or other identifiable local cause. Following urgent specialist assessment, a biopsy is performed. Which histopathological finding most strongly supports an oral melanotic macule rather than oral melanoma?

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Correct answer: C — Increased melanin within basal keratinocytes, without melanocytic proliferation or cytological atypia

Explanation lettering: E = shown as A · C = shown as B · A = shown as C · B = shown as E

The defining pattern of an oral melanotic macule is increased melanin production and deposition in basal keratinocytes, with a normal melanocyte population and no cytological atypia. Early oral melanoma may be clinically indistinguishable, particularly at a high-risk site such as the palate, so histopathological assessment is required. Confluent atypical melanocytes with pagetoid spread or invasion indicate melanoma (D). Intraepithelial dendritic melanocyte proliferation with acanthosis suggests oral melanoacanthoma (B), while nests of bland naevomelanocytes support a melanocytic naevus (C). Haemosiderin-laden macrophages indicate previous haemorrhage or a vascular-related pigment rather than a melanotic macule (E).

Reference: Page LR, Corio RL, Crawford BE, Giansanti JS, Weathers DR. The oral melanotic macule. Oral Surgery, Oral Medicine, Oral Pathology. 1977;44(2):219-226. https://pubmed.ncbi.nlm.nih.gov/268573/