proposed that thickness of the tumour, cervical lymph node metastasis, presence or absence of ulceration and the anatomic sites are all independent risk factors. Differential diagnosis includes physiologic pigmentation, nevi, oral melanotic macules, Kaposi's sarcoma, oral melanoacanthoma
and amalgam tattoos.
Most of the lesions were more common in females except for melanoacanthoma
where the only case was found in a male.
(3) Brown or dark pigmentation or discoloration of the gingival tissue is however considered as multifactorial, including genetic factors, tobacco use, systemic disorders (endocrine disturbance, Albright's syndrome, malignant melanoma, Peutz-jeghers syndrome, hemochromatosis, Addison's syndrome and von Recklinghausen's disease), antimalarial drugs, heavy metals (silver, bismuth, mercury, lead), zidovudine, amalgam tattoo, nevus, melanoacanthoma
, kaposis sarcoma.
Many names are applied to this lesion (senile wart, melanoacanthoma
), but seborrheic keratosis is the most widely accepted.
Presence of atypical melanocytes in the SC strongly suggests a possible malignant melanoma (Figure 8(b)), but also, in rare instances, a benign melanoacanthoma
[7, 8, 26, 27].
Clinical variants of seborrhoeic keratosis include dermatosis papulosa nigra, stucco keratosis and melanoacanthoma
. We did not come across any report of seborrhoeic keratosis presenting as bilaterally symmetrical linear verrucous lesions on inguinal folds.
is an uncommon benign pigmented reactive lesion of the oral mucosa with no malignant potential.