A clinicopathological and immunohistochemical analysis of primary oral mucosal melanoma

Primary Malignant Melanoma of Tongue: Rare and Aggressive Malignant Tumor

Primary melanoma of the oral cavity is extremely rare, accounting for 0.2-8% of all melanomas. Lesions arising from mucosal melanocytes occur most frequently on the gingiva or palate. Mucosal melanomas carry a worse prognosis than cutaneous melanomas. Very few studies have been published due to rarity of disease. 46 year old lady presented with black colored lesion over left side of her tongue for 6 weeks. On examination there was 3 × 2.5 cm black colored patch over left lateral part of tongue in middle 1/3rd, not crossing midline. Tip and base of tongue were free. Biopsy was suggestive of malignant melanoma of tongue. Patient underwent surgery (wide local excision of left lateral border of tongue lesion + left selective neck dissection). Final Histopathological report revealed malignant melanoma of tongue with all margins free, Depth of invasion 3 mm, Lympho-vascular invasion present, and no perineural invasion, left level III cervical lymph node metastases. Patient thus received adjuvant RT. Immunotherapy was also advised in multidisciplinary clinic, but patient was non-compliant. Early diagnosis will be promoted by careful oral examination and early biopsy of pigmented and non-pigmented masses. Early diagnosis and treatment will improve the prognosis of patients with oral malignant melanoma.

Pevonedistat targeted therapy inhibits canine melanoma cell growth through induction of DNA re-replication and senescence

MLN4924 (pevonedistat) is a potent and selective NEDD8-activating enzyme (NAE) inhibitor. The NEDD8-regulated neddylation system is responsible for the regulated degradation of intracellular proteins with important cellular functions in cancer cell growth, apoptosis, angiogenesis and metastasis. In human melanoma, inhibition of NAE results in induction of DNA re-replication, S phase cell cycle arrest, DNA damage and apoptosis. The study aimed to assess the anti-cancer effect of MLN4924 on canine malignant melanoma cell lines and patient samples and to elucidate the underlying mechanisms. Canine melanoma cell lines and primary patient samples were evaluated for cell viability after incubation with varying concentrations of MLN4924 or dimethyl sulfoxide. Apoptosis, cell proliferation and senescence assays were performed to address underlying mechanisms of MLN4924-mediated anti-tumour effects. Gene expression of seven previously identified deregulated genes in human melanoma was compared in sensitive vs resistant samples. MLN4924 treatment significantly reduced the viability of canine melanoma cell lines and primary samples in a dose- and time-dependent manners. MLN4924 promoted cell apoptosis and inhibited cell growth through induction of DNA re-replication and cell senescence. While the majority of canine melanoma samples demonstrated sensitivity at nanomolar ranges, some samples were resistant to the treatment. Modulation of P21 levels correlated with canine melanoma cell sensitivity. These results provided justification for further exploration of MLN4924 as a treatment of canine melanoma.

Primary mucosal melanoma of the oral cavity: current therapy and future directions

BACKGROUND

Primary mucosal melanoma of the oral cavity is a highly aggressive malignancy of melanocytic origin. The aim of this study is to report a case series of oral mucosal melanomas (OMMs) and provide a review of the literature with regard to treatment guidelines for and prognosis of this pathologic entity.

STUDY DESIGN

We report three cases of OMMs treated in our institutions and the results of a literature review, in which the words "oral" and "mucosal melanoma" were used as the main keywords.

RESULTS

Surgical resection of the primary tumor with wide resection margins appears to be the recommended primary treatment modality with the aim to achieve tumor-free margins. Elective neck dissection and adjuvant radiotherapy have been advocated for locoregional control. Chemotherapy has not been shown to improve survival and is mainly used for palliative purposes. Immunotherapy and biochemotherapy seem to significantly improve survival and could open new therapeutic horizons.

CONCLUSIONS

The prognosis of OMMs remains poor despite treatment. Early diagnosis and aggressive surgical resection followed by adjuvant therapies could be the key to improving survival. Multicenter randomized clinical trials, which may be difficult to conduct because of the rarity to the lesion, would aid in the development of new strategies.

A rare case of amelanotic malignant melanoma in the oral region: Clinical investigation and immunohistochemical study

Amelanotic malignant melanoma (AMM) is rare in the oral region. The present study examined the clinical features of this tumor in an attempt to establish diagnostic criteria. The expression of three melanocytic differentiation markers, HMB-45, S-100 and Melan-A, was also measured in primary oral AMMs in order to determine whether the markers could be used to diagnose primary oral AMMs and to find out which marker was the most sensitive. It may be particularly difficult to correctly diagnose AMM that lacks a radial growth phase without immunohistochemical assistance. In the present study, mixtures of polygonal and spindle cells at different ratios were observed in the tumors with and without a radial growth phase. Immunohistochemistry was used to examine the HMB-45, S-100 and Melan-A expression in the formalin-fixed paraffin-embedded specimens of primary oral AMMs. Comparison of staining intensities (SIs) and labeling indices (LIs) of the markers was also performed. The immunostaining results revealed that the SI of Melan-A was significantly higher than that of S-100 (P=0.0011). HMB-45, S-100 and Melan-A also exhibited high positive rates and LIs in AMMs and, therefore, may be good markers for the immunohistochemical diagnosis of primary oral AMMs. Furthermore, Melan-A may be a more sensitive marker than S-100 and HMB-45, as it has a higher SI.

Development of an allogeneic whole-cell tumor vaccine expressing xenogeneic gp100 and its implementation in a phase II clinical trial in canine patients with malignant melanoma

A xenogeneic melanoma-antigen-enhanced allogeneic tumor cell vaccine (ATCV) is an appealing strategy for anti-cancer immunotherapy due to its relative ease of production, and the theoretical possibility that presentation of a multiplex of antigens along with a xenogeneic antigen would result in cross-reaction between the xenogeneic homologs and self-molecules, breaking tolerance and ultimately resulting in a clinically relevant immune response. In this study, we evaluated the efficacy of such a strategy using a xenogeneic melanoma differentiation antigen, human glycoprotein 100 (hgp100) in the context of a phase II clinical trial utilizing spontaneously arising melanoma in pet dogs. Our results demonstrate that the approach was well tolerated and resulted in an overall response rate (complete and partial response) of 17% and a tumor control rate (complete and partial response and stable disease of >6 weeks duration) of 35%. Dogs that had evidence of tumor control had significantly longer survival times than dogs that did not experience control. Delayed type hypersensitivity (DTH) to 17CM98 canine melanoma cells used in the whole cell vaccine was enhanced by ATCV and correlated with clinical response. In vitro cytotoxicity was enhanced by ATCV, but did not correlate with clinical response. Additionally, anti-hgp100 antibodies were elicited in response to ATCV in the majority of patients tested; however, this also did not correlate with clinical response. This approach, along with further elucidation of the mechanisms of tumor protection after xenogeneic immunization, may allow the development of more rational vaccines. This trial also further demonstrates the utility of spontaneous tumors in companion animals as a valid translational model for the evaluation of novel vaccine therapies.

Transformation of a benign oral pigmentation to primary oral melanoma

OBJECTIVE

The objective is to report the serendipitous 7-year follow-up and transformation of a melanotic palatal lesion, which was initially diagnosed histologically as a benign oral melanotic macule, into primary oral melanoma and to provide long-term follow-up of a case of oral malignant melanoma.

STUDY DESIGN

Nine formalin-fixed paraffin-embedded tissue blocks from several different facilities and microscopic slides of the patient's lesions were reviewed to study the transformation of a benign, oral, pigmented lesion into melanoma.

RESULTS

Review of blocks and slides of the patient's lesions suggest that the onset of melanocytic hyperplasia (increased clear cell activity) heralded the transformation of the melanotic macule into melanoma. The histology of the first biopsies was totally benign, but retrospectively, the clinical appearance was not typical and was somewhat worrisome because of the size of the lesion and feathering of the pigmentation at the periphery. This clinical presentation, however, was unknown to the pathologists.

CONCLUSIONS

This study documents a case of primary oral melanoma arising from an apparent oral melanotic macule and suggests that even histologically benign-appearing oral melanotic lesions should perhaps be viewed with caution if increased numbers of melanocytes (melanocytic hyperplasia or clear cell activity) are present. Careful correlation of clinical appearance and histology is necessary to arrive at an appropriate diagnosis and prognosis for oral pigmented lesions.

HMB-45 may be a more sensitive maker than S-100 or Melan-A for immunohistochemical diagnosis of primary oral and nasal mucosal melanomas

BACKGROUND

Primary mucosal melanomas (MMs) of the head and neck are a rare entity. Melanomas with characteristic melanin-pigmented tumor cells are easy to diagnose, but those without melanin-pigmented tumor cells, amelanotic melanomas, are difficult to identify and need immunohistochemistry (IHC) to confirm the final diagnosis. In this study, we examined the expression of three melanocytic differentiation markers, HMB-45, S-100, and Melan-A in primary oral and nasal MMs. We tried to evaluate whether HMB-45, S-100, and Melan-A were useful for diagnosis of primary oral and nasal MMs and to find out which marker was the best of the three.

METHODS

This study used IHC to examine the expression of HMB-45, S-100, and Melan-A in 17 formalin-fixed paraffin-embedded specimens of primary oral and nasal MMs. The staining intensities (SIs) and labeling indices (LIs) of HMB-45, S-100, and Melan-A in 17 MMs were calculated and compared between any two markers.

RESULTS

Immunostaining results showed that the positive rate was 94% (16 of 17) for HMB-45, 88% (15 of 17) for S-100, and 71% (12 of 17) for Melan-A in 17 MMs. The SI of HMB-45 was significantly higher than that of S-100 (P = 0.0011) or of Melan-A (P = 0.0034). In addition, the mean LI of Melan-A (59 +/- 43%) was significantly lower than that of HMB-45 (83 +/- 28%, P = 0.0065) or of S-100 (79 +/- 33%, P = 0.0237).

CONCLUSIONS

Our results indicate that both HMB-45 and S-100 show a high positive rate and LI in MMs and therefore may be good markers for immunohistochemical diagnosis of primary oral and nasal MMs. In addition, HMB-45 may be a more sensitive marker than S-100 because HMB-45 shows a significantly higher SI than S-100 in this study.

Intraoral melanoma: long-term follow-up and implication for dental clinicians. a case report and literature review

Primary intraoral melanoma is a rare neoplasm with a poor prognosis, accounting for 1% to 8% of all melanoma in Europe and the United States. The incidence (12%) and 5-year survival rate (17.4%) are higher in Japan. We report a case of oral lentiginous melanoma in a Japanese-American man who survived disease-free for more than 5 years after surgery, radiation therapy, and chemotherapy but developed chronic mucositis of the palate under the denture in the primary radiated field. This lesion responded to antifungal therapy. Subsequent multiple biopsies ruled out the recurrence of melanoma but demonstrated prolonged melanocytic hyperplasia and focal epithelial atypia. We reviewed clinical differences in oral melanoma reported in the United States and Japanese literature, and describe the wide variety of oral clinical features of postoperative radiation and chemotherapy, as well as the oral tissue changes caused by denture-induced mucositis and candidiasis in such patients. Dental clinicians should conduct a thorough head, neck, and oral follow-up with increased vigilance in patients with a history of prior cancer.

Cellular neurothekeoma of the oral mucosa

Cellular neurothekeoma is an unusual benign neoplasm which, despite its name, is of uncertain origin. This report describes a cellular neurothekeoma of the cheek mucosa, the first at this site. The tumour presented in a 29-year-old man as a discrete mucosal thickening. Histology showed a generally well circumscribed, but unencapsulated, solid tumour which replaced the entire lamina propria and permeated between minor salivary glands and bundles of striated muscle in the submucosa. There was a sub-epithelial Grenz zone. The tumour was composed of nodules of pale, epithelioid cells separated by fascicles of spindle cells, with smaller strands and nests superficially. The nuclei were vesicular and, though mainly bland, occasionally atypical. The stroma was moderately infiltrated by mixed chronic inflammatory cells. Prominent nerves and blood vessels were seen at the periphery of the lesion, and neoplastic cells were noted within intact striated muscle fascicles. With immunohistochemistry, all the neoplastic cells strongly expressed NKI/C3, synaptophysin, neurone-specific enolase and vimentin, some expressed smooth muscle actin and PGP 9.5, but all were negative for S100, factor XIIIa, CD34, CD56, CD57, CD68, chromogranin A, desmin, epithelial membrane antigen and von Willebrand factor. The origin of the lesion is thus speculative. It was, however, completely excised and in 12 months there has been no recurrence.

Malignant melanoma of the oral cavity: diagnosis and treatment experience in a Mexican population

Oral malignant melanoma is uncommon, accounting for 1-8% of all malignant melanomas. All previous papers have reported small numbers of cases or have retrospectively reviewed case reports from the literature. The following case reports concern malignant melanoma of the oral cavity seen at the Instituto Nacional de Cancerología, Mexico City, during the period of 1982-96. Demographic, clinical and histopathological data were collected. Our 15 patients consisted of 6 males and 9 females. The mean age was 52.6 years (range: 35 to 80 years). The hard palate was the most common area affected with 11 cases (73%). At the time of the initial examination, a pigmented mass was apparent in 100% of the patients. All our surgical cases were treated with wide resection; 8 patients received adjuvant radiation, 4 were treated with surgery alone and 1 case received radiation and chemotherapy before the surgery. Local control of the primary lesion was possible in 14 of the 15 cases. Some patients received therapeutic or elective lymph node dissection. The median survival was 16.9 months (mean: 12.5 months). The 2- and 5-year survival rates were 26.6 and 6.6%, respectively.

Oral mucosal melanomas: the WESTOP Banff workshop proceedings. Western Society of Teachers of Oral Pathology

A workshop to discuss primary oral melanomas was convened at the annual Western Society of Teachers of Oral Pathology meeting in Bannf, Alberta, Canada. Fifty oral melanomas, identified from the files of the participants, were reviewed in order to better understand the clinical features, histologic spectrum, and natural history of these perplexing lesions. Results confirmed that oral melanomas occur in adults almost three times more frequently in men than women and have a decided predilection for the palate and gingiva. Some lesions exhibit a clinically detectable and prolonged in situ growth phase, whereas others seem to lack this property and exhibit only or predominantly invasive characteristics. Recurrences, metastases, and death from tumor were characteristic of the follow-up of a limited number of patients. Until definitive prospective data are collected that elucidate natural history, oral mucosal melanomas should be tracked separately from cutaneous lesions. All oral pigmented lesions that are not clinically diagnostic should be biopsied. Lesions with equivocal histopathologic features might be referred to as "atypical melanocytic proliferation" and should be excised. Recognition of lesions in an early in situ phase and aggressive treatment should have a favorable effect on prognosis. To enhance future or prospective study of these rare neoplasms, guidelines for reporting oral melanomas are suggested.

The immunohistochemical identification of human oral mucosal melanocytes

With the aim of identifying melanocytes, 60 samples of wax-embedded palatal and buccal mucosa front 30 autopsies were analysed for expression of S100, HMB-45 and NKI/C3 in combination with a Masson Fontana stain. The counts of positive cells were compared with those derived from 3,4 dihydroxyphenylalanine (DOPA) staining in fresh samples of gingiva. Polyclonal antisera to S100 stained dendritic cells throughout the epithelium, but monoclonal antibodies to S100, HMB-45 and NKI/C3 labelled cells that were restricted to the basal layer, often in clusters with some sections negative. The mean counts of positive basal dendritic cells per millimetre basement-membrane length were 4.3 (polyclonal S100+. range 0-19). 0.8 (monoclonal S100+. range 0-7.3), 2.0 (HMB-45, range 0-17.8) and 0.9 (NKI/C3, range 0-14.9). Of the last three, HMB-45 produced the clearest and most specific staining. Counts of basal dendritic cells were significantly higher (p < 0.0005) with polyclonal antisera to S100 than with all other markers except DOPA but HLA-DR staining showed that Langerhans cells may also be located in the basal layer. The highest values were always in buccal mucosa, but statistically significantly so (p < 0.0005) only with polyclonal anti-S100. Basally located DOPA+ cells had a mean density of 4.6 per millimetre basement-membrane length, but in five cases DOPA also labelled suprabasal dendritic cells, presumably Langerhans cells. The mean basal DOPA+ values were significantly higher than those with monoclonal antibodies to S100. HMB-45 and NKI/C3 (p < 0.001). The variable cell counts suggest that S100, HMB-45 and NKI/C3 are markers of melanocytes in normal oral mucosa, but are not constitutively expressed and may be induced during function.