Desmoplastic malignant melanoma of the gingiva

Desmoplastic melanoma of the oral cavity: diagnostic pitfalls and clinical characteristics

Objectives

Desmoplastic melanoma of the oral cavity is an extremely rare condition that is often confused on initial diagnosis with non-melanotic benign lesion or spindle cell tumors. The purpose of this article was to raise awareness of the disease using a literature review.

Materials and Methods

We analyzed 19 desmoplastic melanoma cases reported in the literature and added our experience. Data on clinical, histopathology, treatment, and survival were retrieved and analyzed. Survival analysis was by the Kaplan-Meier method.

Results

Initial clinical and histopathological features were indistinctive, and a definite diagnosis of desmoplastic melanoma at initial assessment was possible in only 23.5% of cases. Among tests, immunohistochemical studies for S-100 and vimentin were all positive. The 5-year disease-free survival rate for oral desmoplastic melanoma was 0%, and the 5-year overall survival rate was 55.0%.

Conclusion

Oral desmoplastic melanoma has a high percentage of initial misdiagnosis and propensity for local recurrence. Thus, careful initial diagnosis and adequate surgery may result in improved overall survival.

Exophytic Tumor Growth After Incomplete Removal of Polypoid Malignant Melanoma of the Maxillary Gingiva: A Case Report and Review of the Literature

Polypoid malignant melanoma of the oral cavity is extremely rare. This report describes the case of the 3-time occurrence of a polypoid malignant melanoma of the maxillary gingiva in an 84-year-old woman who had removed the primary tumor by herself. The second polypoid malignant melanoma was a black 7-cm pedunculated mass surrounded by pigmented mucosa. Histologically, the tumor exhibited an ulcerated surface lined by squamous cells and contained polygonal cells with brown-and-black pigmentation. The third polypoid malignant melanoma was observed at the same location 7 months after surgery; it was a black hemorrhagic mass approximately 1.5 cm. Histologic analysis showed morphologic findings that were similar to those observed in the second polypoid melanoma. The patient died of lung metastasis 28 months after the second surgery. This report also reviews the 5 previously reported cases of polypoid malignant melanoma of the oral cavity, all of which occurred in the upper jaw. In 2 cases, initial exophytic growth of the tumor before invasion of the submucosa and relatively early detection resulted in a good prognosis. However, in 1 case, amelanotic melanoma located in the periodontal tissues was clinically misdiagnosed as epulis. Therefore, immunostaining for S-100 and HMB-45 should be considered for nonpigmented epulis-like lesions, and wide surgical resection of primary polypoid malignant melanomas at an early stage should result in a favorable prognosis.

Primary mucosal desmoplastic melanoma of the nasal vestibule: the second case

Primary mucosal desmoplastic melanoma is an exceedingly rare, potentially devastating disease that is often initially misdiagnosed because of its deceptively benign presentation. We report what we believe is only the second case of mucosal desmoplastic melanoma arising from the nasal vestibule. The patient, a 62-year-old woman, presented with an obstructive, enlarging mass in the nasal cavity. The tumor, which was initially believed to be benign, was excised, but it recurred 12 months postoperatively. The recurrence was excised, but 4 years later, the patient experienced a second recurrence; in this case, the tumor had invaded the cribriform plate and extended to the anterior cranial fossa. The tumor subsequently metastasized to the dura mater, which led to the patient's death. We review the distinction between conventional mucosal melanoma and mucosal desmoplastic melanoma, and we discuss the ways in which the behavior of a desmoplastic melanoma can point to the diagnosis. Because a diagnosis can be difficult to establish, we stress the importance of maintaining a high index of suspicion when evaluating pathologic and immunohistochemical findings in a patient with a recurrent mucosal nasal mass.

Malignant melanoma in the 21st century, part 1: epidemiology, risk factors, screening, prevention, and diagnosis

Malignant melanoma is an aggressive, therapy-resistant malignancy of melanocytes. The incidence of melanoma has been steadily increasing worldwide, resulting in an increasing public health problem. Exposure to solar UV radiation, fair skin, dysplastic nevi syndrome, and a family history of melanoma are major risk factors for melanoma development. The interactions between genetic and environmental risk factors that promote melanomagenesis are currently the subject of ongoing research. Avoidance of UV radiation and surveillance of high-risk patients have the potential to reduce the population burden of melanoma. Biopsies of the primary tumor and sampling of draining lymph nodes are required for optimal diagnosis and staging. Several clinically relevant pathologic subtypes have been identified and need to be recognized. Therapy for early disease is predominantly surgical, with a minor benefit noted with the use of adjuvant therapy. Management of systemic melanoma is a challenge because of a paucity of active treatment modalities. In the first part of this 2-part review, we discuss epidemiology, risk factors, screening, prevention, and diagnosis of malignant melanoma. Part 2 (which will appear in the April 2007 issue) will review melanoma staging, prognosis, and treatment.

Unusual variants of malignant melanoma

A potential diagnostic pitfall in the histologic assessment of melanoma is the inability to recognize unusual melanoma variants. Of these, the more treacherous examples include the desmoplastic melanoma, the nevoid melanoma, the so-called 'minimal-deviation melanoma,' melanoma with prominent pigment synthesis or 'animal-type melanoma,' and the malignant blue nevus. Also problematic are the unusual phenotypic profiles seen in vertical growth phase melanomas; these include those tumors whose morphological peculiarities mimic cancers of nonmelanocytic lineage and those melanomas that express aberrant antigenic profiles not commonly associated with a melanocytic histogenesis. Metaplastic change in melanoma, balloon cell melanoma, signet-ring cell melanoma, myxoid melanoma, small cell melanoma and rhabdoid melanoma all have the potential to mimic metastatic and primary neoplasms of different lineage derivations. Abnormal immunohistochemical expression of CD 34, cytokeratins, epithelial membrane antigen, and smooth muscle markers as well as the deficient expression of S100 protein and melanocyte lineage-specific markers such as GP100 protein (ie HMB-45 antibody) and A103 (ie Melan-A) also present confusing diagnostic challenges. In this review, we will discuss in some detail certain of these novel clinicopathologic types of melanoma, as well as the abnormal phenotypic expressions seen in vertical growth phase melanoma.

Primary mucosal desmoplastic melanoma of the head and neck

BACKGROUND

Desmoplastic variants of melanoma rarely affect the mucosa.

METHOD

The clinicopathologic features and p53 status of seven primary mucosal desmoplastic melanomas of the oral and nasal cavity were studied.

RESULTS

The patients included six men and one woman (median age, 61 years; range, 23-74 years). Desmoplastic melanoma involved the lip in two, alveolus in three, buccal mucosa in one, and nasal vestibule in one patient. Four tumors infiltrated up to lamina propria, and three infiltrated bone and/or cartilage. All were amelanotic spindle cell tumors, five were neurotropic, and two were vasoinvasive. Aberrant p53 expression was seen in six tumors. All tumors recurred locally, and distant metastasis developed in three. Six patients died with disease (survival, 1-41 years; median, 8 years), and one patient was free of disease (survival 20 years).

CONCLUSIONS

Primary mucosal desmoplastic melanomas are clinically characterized by local recurrence and may lead to distant metastasis and death even after several years. Alterations in p53 expression are frequently associated with desmoplastic melanoma.

Desmoplastic malignant melanoma of the palatal alveolar mucosa: sustained disease-free survival after surgery and postoperative radiotherapy

Aggressive surgical and radiotherapeutic management of a patient with desmoplastic malignant melanoma arising from the mucosa of the oral cavity has resulted in disease-free survival of more than 2(1/2) years after diagnosis. This case represents only the tenth reported instance of desmoplastic malignant melanoma arising from the oral cavity and only the third for which survival has exceeded 2 years. Details of the clinical, histopathologic, and therapeutic features of the case are provided to augment the paucity of literature available to clinicians managing this rare disease.

Neoplasms with neural differentiation: a review. Part II: Malignant neoplasms

Malignant peripheral nerve sheath tumors (MPNSTs) encompass a wide and unusual group of neoplasms with features of neural differentiation. They most commonly present as spindle cell neoplasms and it can be difficult to differentiate them from other spindle cell neoplasms such as leiomyosarcomas, fibrosarcomas and synovial sarcomas. Strict criteria need to be applied in order to make the diagnosis of MPNSTs. Helpful features include contiguity with a nerve or an association with von Recklinghausen disease. The use of immunohistochemical stains may also help to confirm the diagnosis. Markers such as S-100 protein, neurofilament, epithelial membrane antigen and Leu-7 (CD57) are frequently used to assess neural differentiation in these neoplasms. In addition to the spindle cell pattern, MPNSTs may also display an epithelioid pattern. Rarely, other elements may be seen including glands in the so-called glandular MPNST or muscle in triton tumors. In more unusual cases cartilage, adipose tissue and even bone are present. Also included in the group of MPNSTs are the peripheral neuroepithelial tumor, neurotropic or desmoplastic melanomas and malignant granular cell tumors. MPNSTs are highly aggressive tumors and should be treated accordingly.

Desmoplastic malignant melanoma of the gingiva: case report and review of the literature

A rare case of desmoplastic melanoma arising from the maxillary gingiva of a 66-year-old woman is reported. This tumour metastasised to the submandibular lymph node 5 years after extirpation, and local recurrence was observed 2 years later. The gingival tumour showed the histopathological characteristics of desmoplastic melanoma and the metastasised tumour cells were immunohistochemically positive for S-100 protein, neuron specific enolase, HMB-45 highly specific for conventional melanoma, and Fontana-Masson staining. The gingival tumour, originally regarded as benign clinically, was actually a desmoplastic melanoma.

Desmoplastic malignant melanoma of the oral mucosa. An underrecognized diagnostic pitfall

BACKGROUND

Although cutaneous desmoplastic malignant melanoma (DMM) has been well characterized, those arising from the oral mucosa have been less well defined.

METHODS

We evaluated the clinical and pathologic features of three patients with biopsy-proven DMM examined at the North Carolina Baptist Hospital. Routine hematoxylin and eosin-stained slides were reviewed in all three cases. Sections from all cases were examined immunohistochemically using the avidin-biotin-peroxidase (ABC) technique and employing commercially available antibodies to the following antigens: S-100 protein, HMB-45, NK1C3, and cytokeratin (AE1/AE3). Appropriate positive and negative controls were utilized throughout these procedures. Clinical data were obtained from the patients' medical records.

RESULTS

Age at diagnosis for the three male patients were 42, 64, and 75 years. Anatomically, these neoplasms arose from the left maxillary oral mucosa (two patients) and the vermilion border of the lower lip (one patient). Initial incisional biopsies of all three patients were misinterpreted as desmoid tumor (one patient) and squamous cell carcinoma (two patients), respectively. Histologically, all tumors were poorly circumscribed and composed of fascicles and bundles of spindle-shaped cells with hyperchromatic nuclei and associated with extensive stromal collagenization. Perineural invasion was noted in two tumors. An overlying atypical, intraepidermal melanocytic proliferation was observed in two tumors. Immunohistochemically, all three tumors showed positive immunoreactivity with S-100 protein and vimentin. One tumor also expressed HMB-45. Wide surgical incision was the primary mode of therapy in all patients. One patient also received multiple courses of radiation therapy and chemotherapy. One patient died of widespread metastatic disease.

CONCLUSIONS

DMM of the oral mucosa is a rare, often unrecognized, form of malignant melanoma associated with a fibrosarcoma-like morphologic appearance and abundant collagenization. Meticulous attention to histomorphology and judicious use of immunohistochemical stains will help prevent misdiagnosis.

Desmoplastic neurotropic melanoma. A clinicopathologic analysis of 28 cases

BACKGROUND

Desmoplastic neurotropic melanoma (DNM) is a rare variant of malignant melanoma, the natural history and histogenesis of which still are being defined.

METHODS

The clinical and histologic features of 28 cases of DNM were studied. All published cases of DNM to date were reviewed. Paraffin sections from 26 cases were investigated with a panel of 10 tissue markers. The ultrastructural features of seven cases were evaluated.

RESULTS

A comparison of this study's findings with that of other published cases revealed many similarities regarding clinical and pathologic findings and outcome. The patients were white (15 men:13 women; mean and median age, 59 years; range, 22-83 years). Most tumors were located on the head and neck (75%) and were nonpigmented (57%). An associated intraepidermal melanocytic proliferation was identified in 85% of the patients (lentigo maligna in 56%). Histologically, the dermal tumors were composed of tapered, nonpigmented spindle cells in peripheral nerve sheath patterns resembling neuromas, schwannomas, neurofibromas, and perineurial proliferations accompanied by variable neurotropism and desmoplasia; desmoplasia was the most notable feature in most tumors. The mean depth of tumor invasion was 4.1 mm (range, 0.32-9.0 mm). Tumors with continuity between the epidermal and dermal components had a significantly thinner depth of invasion and a more extensive intraepidermal melanocytic proliferation than those tumors with a grenz zone between the two components (2.3 mm vs. 4.6 mm, P = 0.015). Mitotic activity ranged from 0/HPF in 10 cases, 1-6/high power field (HPF) in 12 cases, and to greater than 6/HPF in 4 cases. An ulcer was present in 5/27 tumors, regression in 4/27, a microsatellite in 1, and brisk and had nonbrisk tumor infiltrating lymphocytic responses in 2 and 14, respectively. Vimentin was uniformly positive and keratins AE1.3 and Cam 5.2 and Leu-7 were uniformly negative. S100 protein, also uniformly positive, had patchy reactivity in most tumors that expressed EMA (43%). Smooth muscle actin (52%), neuron-specific enolase (42%), and FXIIIa (30%) had patchy positivity. HMB-45 was reactive only in the epidermal and superficial papillary dermal component in 21% of cases. Ultrastructurally, the common features were long, often intertwining cellular processes, intercellular junctions, and discontinuous basal lamina. Melanosomes were not identified. Follow-up data available on 26/28 patients (mean, 36 months; median, 24 months; range, 5-132 months) showed 20 (70%) alive without disease, 2 alive with disease and 3 dead from disease. Seven patients had recurrent local tumor (multiple in four); four had lymph node metastases, and three had visceral metastases. Patients with recurrent disease of any type had significantly thicker tumors (5.4 mm vs. 3.4 mm, P = 0.046) and were more likely to have an ulcerated tumor (P = 0.03). Actuarial 5-year survival for tumors with greater than a 4-mm thickness was 72%, which was greater than that for other types of melanoma with greater than a 4-mm thickness.

CONCLUSIONS

Desmoplastic neurotropic melanomas are neuroectodermal tumors that usually arise from an intraepidermal melanocytic proliferation but rarely develop de novo in the dermis. Schwannian and perineurial differentiation may account for the desmoplasia and neurotropism encountered in these neoplasms. Desmoplastic neurotropic melanomas present at a more advanced stage locally and may be associated with a better survival than associated with conventional melanomas of similar depth of invasion.

S100 protein in oral biology and pathology

The demonstration of S100 protein is used extensively for both research and diagnostic purposes in oral biology and pathology. This article reviews the structure and putative function of S100, technicalities of S100 immunohistochemistry, the cells of the oral and perioral tissues which express S100 and the possible significance of S100 expression in disease.

Desmoplastic malignant melanoma: a clinicopathological study of 25 cases

Sixteen cases of malignant melanoma which showed prominent desmoplastic and/or neurotropic features occurring throughout the tumour were compiled from the St John's Dermatology Centre histopathological archives. A further nine melanomas in which both conventional and desmoplastic melanoma were present concomitantly were also studied (three tumours with 66% desmoplastic change, two with 50%, and four with less than 50%). There were 14 males and 11 females, with a mean age of 64 years (range 39-86). The mean interval between presentation and diagnosis was 8 months. Eighteen of the 25 tumours were located on the head and neck, three were on the trunk, one was on the upper limb and three were on the lower limb. Histological review revealed 21 of 25 tumours with overlying atypical lentiginous hyperplasia, lentigo maligna melanoma, or superficial spreading malignant melanoma. Neurotropism was present in nine tumours, with the changes confined to local recurrences in two instances; neuroid differentiation was present in four tumours, and neural and perineural tumour spread was present in four tumours. The depth of invasion exceeded 6 mm in seven tumours, and was 2-6 mm in 16, and less than 2 mm in two. Eighteen of the 25 tumours were incompletely excised at the time of the first excision. Lymphoid aggregates were present in 16 tumours, but in most cases were limited to a few lymphoid foci. Melanin was identified in the dermal component of only five tumours, but not in areas showing typical histological features of desmoplastic malignant melanoma. Treatment was by surgical excision in all cases, and was preceded by radiotherapy in one case. Details of follow-up were obtained in all cases, and the duration ranged from 9 months to 10 years (mean, 3 years 11 months). Eleven patients had died; nine from melanoma and two from other causes. One patient was alive, with deep, inoperable local recurrence. Thirteen patients were alive and clinically free from tumour, including two patients in whom there had been local recurrence. A lower rate of neurotropism was present in the nine patients with partial desmoplastic change compared with those with desmoplasic change throughout the tumour, and represented the only significant difference between the two groups of patients.