Search

A pigmented nevus is defined as a hamartomatous proliferation of nevus cells, and it is a most common skin lesion. Pigmented nevi of the oral mucosa are considered to a rare lesion with only a few cases being reported in Japan. Here, an intradermal nevus on the palate is described together with the results of immunohistochemical studies. A 44-yearold man had noted pigmentation and swelling of the palate for few years, but it was asymptomatic and not treated previously. The lesion was diagnosed to be an intradermal nevus histopathologically, and numerous melanocytic masses were seen in the connective tissue under the palatal epithelia. The melanin pigment stained with Masson-Fontana stain. Immunohistochemically, the following antibodies were tested: PoAb S-100 protein, MoAb S-100α, MoAb S-100β, MoAb or PoAb neuronspecific enorase (NSE), PoAb substance P, MoAb chromogranin A, keratin (MoAb K8.12, KL1), MoAb vimentin, and MoAb glial fibrillary acidic protein (GFAP). The melanocytes were positive to PoAb S-100 protein, MoAb S-100/β and MoAb vimentin.

A pigmented nevus is defined as a hamartomatous proliferation of melaninproducing cells (nevus cells). A relatively rare case of the disease with involvement of the oral mucosa is reported.The patient was a 44-year-old woman who had a nevus on the alveolar mucosa of the maxilla for about 7 years. The nevus measured 33×23mm, but was asymptomatic. A biopsy showed the lesion to be an intradermal nevus. Because of the location of the nevus and the patient's past history of schizophrenia, the lesion was resected with the patient under general anesthesia. Postoperative healing was uneventful, and there was no evidence of recurrence as of 4 years 6 months after the operation.

A pigmented nevus is defined as a hamartomatous proliferation of nevus cells. It is a very common skin lesion. Pigmented nevi of the oral mucosa are considered a rare lesion and only a few cases have been reported in Japan.We recently encountered 2 cases of pigmented nevus. The first case was in a 26-year-old man. The nevus was located on the buccal mucosa and measured 4×5mm. The other case was in a 23-year-old woman. She had a nevus on the palatal mucosa for about 15 years. The nevus had grown slowly and measured 40×18×5mm at the time of presentation. She had no symptoms. The nevus was resected in both patients. There has been no recurence in either patient as of 2 year after the operation.

A pigmented nevus is defined as a harnartomatous proliferation of the melaninproducing cells (nevus cells). It is a relatively rare disease, especially in the oral mucosa. In this report, the authors present a case of a pigmented nevus of the gingiva, and review 18 cases of pigmented nevus in the region of mucous membrane or lip as previously reported in Japanese medical literature.The patient, a 63-year-old woman, was referred by her dentist complaining of denture instability due to swelling of the gingiva. About six months ago, she first noted the swelling on the left mandibular gingiva, in the area of the cuspid. The swelling gradually enlarged. At the time of oral examination, a well-defined pigmented swelling about the size of a red bean was noticed.Having been clinically diagnosed as fibroma, the lesion was surgically excised with little difficulty.A histopathological study revealed it to be an intramucosal pigmented nevus.Postoperative healing was uneventful and there has been no evidence of recurrence after a lapse of 1 year and 8 months.

A pigmented nevus is defined as a hamartornatous proliferation of the melaninproducing cells (nevus cells). It is usually rare on the oral mucosa, especially the junctional type. In this report we presented the junctional typed nevus on the palate and its treatment using the laser vaporization.The patient was a 77-year-old man. About two years ago he was pointed out the pigmentation on the left hard palate by a dentist. But as the lesion was a symptomatic, he had received no cure. At the beginning of Oct. 1981 when he had the dental treatment, the increased pigmentation was pointed out again and he was referred to our university clinic by the same dentist. He had been diagnosed as having hypertension and chronic bronchitis five years before and had the operations for gastric ulcer three times. In the clinical examination of the oral cavity, a black, irregularly shaped, pigmentation approximately 20×8 mm was observed on the hard palate. The lesion was smooth and flat and not elevated. It had no ulcer or bleeding. The tomography of the maxilla showed no invasive destruction of the bone.Aa biopsy revealed histopathologic changes indicating a junctional typed nevus, we performed CO2 laser vaporization using Surgical laser system 400, a product of Coherent, on Jan. 19, 1982. It was done under the focused beam, continuous wave and the range of 10-15 w output. At follow-up two years postoperatively, the patient was free of symptoms.By light microscopic findings there observed many nevus cells containing melanin pigment in the basal and parabasal layers of the epithelium, but not in the deep area of dermis. By electron microscopic findings nevus cells contained melanin granules of various sizes. Tonofilaments were not observed in the cells, and no desmosomes around the cells.

We reported the clinicopathological features of primary malignant melanoma of the oral cavity in the Part I and II. In this Part, we studied 20 cases of benign and premalignant pigmented lesion in the oral mucosa. The 20 cases consisted of 1 premalignant and 19 benign (4 pigmented nevi, 12 non-nevoid melanocytic lesions, and 3 others) lesions.Pigmented nevus was divided into three types; junctional, compound and intramucosal nevus. Non-nevoid melanocytic lesion showed various degree of proliferation of dendritic or clear cell-like melanocytes, hyperpigmentation in the basal cell layer, and phagocytosis of melanin in the connective tissue.One case of premalignant melanocytic lesion occurring in the lower lip had two phases; the plaque and the macular lesions. The plaque lesion revealed proliferation of atypical melanocytes and small nest formation along the basal cell layer. The macular lesion consisted of mild proliferation of melanocytes having no cellular atypia, and hyperpigmentation in the basal cell layer. According to these findings, the lesion was considered to be precursor of ALM.Precursor lesion of oral malignant melanoma has not been well documented. We discussed here the potential of malignant transformation of pigmented nevus and non-nevoid melanocytic lesion of the oral mucosa.