Primary malignant melanoma of the nasal cavity: a clinicopathologic study of nine cases

Surgery alone versus post-operative radiotherapy for sinonasal malignant melanoma: a meta-analysis

OBJECTIVE

Sinonasal malignant melanoma is a relatively rare malignancy with poor prognosis, and effective treatments remain elusive. This analysis aimed to explore whether post-operative radiotherapy conferred any survival advantages in patients with this disease when compared with surgery alone.

METHODS

Published studies were identified by searching four electronic databases. The endpoints evaluated were: rates of overall survival, disease-free survival and local control.

RESULTS

Twenty-eight studies including 1392 patients were identified. The results indicated that post-operative radiotherapy led to a significantly better three-year overall survival rate (p = 0.02), and suggested a borderline significant benefit for five-year overall survival (p = 0.05), when compared with surgery alone. However, no statistical advantage was found for disease-free survival, local control or one-year overall survival.

CONCLUSION

This meta-analysis indicated that adjuvant radiotherapy prolonged survival, but showed no benefit for disease-free survival or local control.

The management and site-specific prognostic factors of primary oral mucosal malignant melanoma

Primary oral mucosal malignant melanoma (POMM) is uncommon. Its biological behavior is more aggressive than that of cutaneous malignant melanoma. Its site-specific prognostic factors and optimal management have not been determined yet. Retrospective POMM case analysis from peer-reviewed publications in the PubMed and Embase electronic database from January 1984 to December 2013, in which therapy and outcome data were available, was performed. A total of 151 primary cases were extracted from 39 peer-reviewed English literatures. The study population includes 63 males and 88 females with a medium age of 61 years. The treatment protocols include surgery alone (18%), radiotherapy alone (14%), surgery plus radiotherapy (14%), surgery plus chemotherapy (31%), as well as surgery plus chemoradiotherapy (15%) and chemoradiotherapy (8%). The male patients have a higher risk for metastasis than the female patients do (odds ratio [OR]; 3.41, P = 0.021). The POMM originating from specialized mucosa was associated with increased risk for tumor recurrence and mortality (OR, 4.03, P = 0.001; OR, 2.03, P = 0.031, respectively). The patients who had surgery-based multiple therapy have a significantly longer survival compared with those who had surgery alone and those who had no surgical treatment (P = 0.000). The age of 60 years or younger (hazard ratio [HR], 4.69; P = 0.000), nonsurgical treatment (HR, 12.838; P = 0.000), and surgery alone (HR, 1.517; P = 0.001) were independent adverse prognostic factors for overall survival. Taken together, the study results suggest that surgery-based multiple therapy is the most effective treatment protocol. The age of 60 years, nonsurgical treatment, and surgery alone were independent adverse prognostic factors for overall survival.

Magnetic resonance imaging (MRI) appearances of primary amelanotic malign melanoma in the nasal cavity: a rare case

Malign melanoma of the nasal cavity that arises at such an unusual location is an exceptional case only occasionally mentioned in the literature. An amelanotic form, which is an uncommon type for this malignancy, also has an unusual radiological appearence from the classic melanotic form. We report here the magnetic resonance imaging (MRI) findings of a 46-year-old man who had a nasal cavity mass diagnosed as an amelanotic malign melanoma and discuss the importance of differential diagnosis with such an unusual radiological manifestation in this location.

[Paranasal sinuses melanoma--a case report]

The malignant melanoma has been presented in majority in the skin location. The mucosal form of melanoma is extremely rare, the localisation involving the structures of paranasal sinuses is the most frequent location according to head and neck region. The authors present the patients case with that location of illness.

Mucosal melanomas: a case-based review of the literature

Mucosal melanoma is a rare cancer that is clearly distinct from its cutaneous counterpart in biology, clinical course, and prognosis. Recent studies have shown important differences in the frequencies of various genetic alterations in different subtypes of melanoma. Activating mutations in the c-KIT gene are detected in a significant number of patients with mucosal melanoma. This observation has resulted in the initiation of several clinical trials aimed at exploring the role of receptor tyrosine kinases that inhibit c-KIT in this patient population. We herein present a comprehensive literature review of mucosal melanoma along with case vignettes of a number of pertinent cases. We further discuss melanomas of the head and neck, the female genital tract, and the anorectum, which are the three most common sites of mucosal melanoma, with a particular focus on the diagnostic, prognostic, and therapeutic data available in the literature.

Primary mucosal melanoma

Primary mucosal melanomas are rare, biologically aggressive neoplasms. The distribution of head and neck, female genital tract, anal/rectal, and urinary tract sites is 55.4%, 18.0%, 23.8%, and 2.8%, respectively. The median age at presentation is the seventh decade, and women are given the diagnosis more frequently than men. Unfortunately, most afflicted individuals harbor micrometastatic disease and experience a course characterized by multiple local recurrences before the clinical development of distant disease. Approximately a third of patients have nodal involvement at presentation, and the overall 5-year survival is only 25%. Despite aggressive surgical resection and a multitude of adjuvant treatments, the prognosis remains grave. Early detection, which is difficult because of the occult anatomic locations in which these tumors occur, allows the best hope for cure.

Nasal melanosis in three dogs

Cytologically and histologically confirmed nasal melanosis was detected by rostrocaudal rhinoscopic evaluation of three dogs with unilateral nasal discharge caused by a chronic and severe odontopathic rhinitis. The extraction of affected teeth and prolonged antibiotic therapy led to a complete resolution of nasal disease. The nasal melanosis could be considered a partial metaplastic transformation of mucosal respiratory cells with accumulation of intracytoplasmic melanin.

Outcomes in sinonasal mucosal melanoma

BACKGROUND

The present paper assesses treatment outcomes in a series of 20 patients with sinonasal mucosal melanoma (SNMM) over 11 years.

METHODS

All patients who presented to a single institution between 1991 and 2002 with a diagnosis of SNMM had their treatment reviewed and outcomes determined.

RESULTS

Twenty patients presented to our institution with SNMM over the study period. No cervical node or metastatic involvement was detected at presentation. The most common site of involvement was the nasal cavity (17/20). The majority of patients received initial surgery followed by radiotherapy (15/20). At the completion of treatment 14 patients had no disease evident. The median time to failure in these patients was 12 months. Of these patients 10 relapsed, including six who had metastatic failure only. Fifteen patients died due to disease. Median overall survival was 17 months, with a 2-year overall survival of 23%. In univariate analysis, patients with advanced tumours (T3-4) had a 4.3 times greater risk of dying than patients with early tumours (T1-2).

CONCLUSIONS

Patients with SNMM have poor outcomes with conventional therapy. Full staging prior to treatment is recommended. Aggressive treatment carrying significant morbidity is justified only for patients with early stage disease.

Malignant melanoma of nasal cavity: report of 16 Japanese patients

BACKGROUND

Primary malignant melanoma of the nasal cavity is a rare disease that has a poor prognosis. There are significant racial differences in the incidence of melanomas in the nasal cavity.

METHODS

Sixteen Japanese patients treated at the Hospital of Tokyo University were reviewed retrospectively.

RESULTS

Fourteen patients were treated with surgery. Two patients received treatment with radiotherapy alone. Seven patients had microscopically negative surgical margins and seven patients had positive surgical margins. The 2- and 5-year actuarial survival rates for all patients were 63.6 and 31.8%, respectively. No statistically significant difference could be shown in the overall survival rate between patients with positive surgical margins and those with negative surgical margins.

CONCLUSIONS

Clinical features of nasal melanoma in Japanese are not different from nasal melanoma in Caucasians. The negative surgical margins were not predictive of a better prognosis.

Postoperative radiotherapy for primary mucosal melanoma of the head and neck

BACKGROUND

Primary head and neck mucosal melanoma (HNMM) has a poor prognosis with a low local control rate and frequent distant metastases. The objective of the current study was to determine the impact of postoperative radiotherapy on local control and survival.

METHODS

One hundred forty-two patients with primary HNMM treated between 1979 and 1997 were reviewed. Of these, 69 patients with confirmed primary mucosal melanoma, absence of metastatic disease, and definitive management by surgery with or without postoperative radiotherapy and follow-up at the Institut Gustave-Roussy (Villejuif) were selected. The site of primary HNMM was sinonasal in 46 patients, oral in 19 patients, and pharyngolaryngeal in 4 patients. Twenty-two patients (32%) had a locally advanced tumor (T3-T4) and 17 patients had regional lymph node metastases after pathologic examination (pN > 0). Thirty patients underwent surgery alone and 39 received postoperative radiotherapy. Patients with locally advanced tumors had received postoperative radiotherapy more frequently than those with small tumors (P = 0.02).

RESULTS

Thirty-seven patients (54%) experienced local disease recurrence and 47 patients (68%) developed distant metastasis. The overall survival rates were 47% at 2 years and 20% at 5 years. In the Cox multivariate analysis, patients with early T-classification tumors who received postoperative radiotherapy had a better local disease-free survival (P = 0.004 and P = 0.05, respectively) compared with patients with late T-classification tumors who did not receive postoperative radiotherapy. Patients with advanced T-classification and pN > 0 stage had a shorter distant metastasis disease-free survival compared with patients with early T-classification and pN < 0 stage. Patients with advanced T-classification tumors had a shorter overall survival compared with patients with early T-classification tumors (P = 0.003).

CONCLUSIONS

The prognosis of patients with HNMM was poor. Patients had a high rate of distant metastasis and a low rate of local control. The current study suggested that postoperative radiotherapy increased local control even for patients with small tumors.

Imaging of neoplasms of the paranasal sinuses

The assessment of sinonasal malignancies requires a multidisciplinary team approach.Advances in pretherapeutic imaging have significantly contributed to the managementof sinonasal tumors. CT and MR imaging play complementary roles in the assess-mentand staging of these malignancies by determining the presence or absence of exten-sionof disease into the skull base and its foramina, the orbit, and the intracranial compartment.

Primary mucosal melanoma of the head and neck: a proposal for microstaging localized, Stage I (lymph node-negative) tumors

BACKGROUND

The current study was conducted to identify histologic predictors of survival in patients with localized, lymph node-negative (Stage I, N0M0) primary mucosal melanomas of the head and neck (HNMM).

METHODS

The histology of 39 sinonasal, 20 oral, 1 pharyngeal, and 1 laryngeal Stage I HNMM was reviewed by 2 pathologists without knowledge of patient outcome. The invasion was evaluated as Level I: melanoma in situ (without invasion or with microinvasion only); Level II: invasion into the lamina propria only; and Level III: invasion into deep tissue (e.g., skeletal muscle, bone, or cartilage). The tumor architecture was defined as pseudopapillary when tumor cells clustered around blood vessels resembling papillae and sarcomatoid when they resembled high-grade pleomorphic sarcoma. Survival analysis was performed with Kaplan-Meier survival curves using disease-specific survival (DSS) as the endpoint.

RESULTS

The 5-year DSS rate was 43% (median, 41.5 months). The median survival was found to decrease significantly with increasing level of invasion: Level I (n = 4): 138 months; Level II (n = 29): 69 months; and Level III (n = 28): 17 months (P = 0.003). The presence of pseudopapillary and sarcomatoid architecture (n = 20) and undifferentiated cells (n = 16) were found to be associated with a significantly poor DSS (P < 0.05). However, on multivariate analysis, only the level of invasion remained an independent predictor of survival (P = 0.03). Tumor thickness, vascular invasion, and necrosis were found to have no significant influence on survival.

CONCLUSIONS

Microstaging according to invasion into three tissue compartments was found to be a significant and independent predictor of poor survival in patients with localized, lymph node-negative, Stage I HNMM. The presence of sarcomatoid and pseudopapillary architecture and undifferentiated cells also appear to be associated with significantly poor DSS.

Clinicopathologic differences in malignant melanoma arising in oral squamous and sinonasal respiratory mucosa of the upper aerodigestive tract

OBJECTIVE

Primary mucosal melanomas are rare tumors. We compare melanomas arising in 2 histologically different mucosa, the stratified oral squamous mucosa and pseudostratified sinonasal respiratory mucosa, to investigate the clinicopathologic influence of native mucosal histology on the tumor.

METHODS

Clinicopathologic features of 36 melanomas arising in the squamous mucosa of the oral cavity were compared with 59 melanomas arising in the sinonasal respiratory mucosa.

RESULTS

The median age of patients was 61 and 63 years for oral and sinonasal melanomas, respectively, with the squamous and respiratory mucosa covering the maxilla being most frequently involved (68.7% and 66%, respectively). The former had a remarkable male predilection (28 men, 8 women), while the latter affected both sexes equally (29 men, 30 women). The oral melanomas were more likely to be detected in the early in situ or microinvasive stage (4 cases vs none, P =.008) and were more frequently amelanotic (14 vs 12, P =.049) than sinonasal melanomas. The sinonasal melanomas were frequently thicker (median thickness, 9 vs 2.6 mm), polypoid (29 vs none), ulcerated (57 vs 20), and necrotic (57 vs 14) than oral melanoma (P <.001). Pseudopapillary architecture was more frequent in sinonasal melanomas (16 tumors vs none, P <.001), and desmoplastic melanomas were more frequent in the oral mucosa (6 vs 1, P =.005). Sinonasal melanoma showed vascular and deep tissue invasion more frequently than oral melanoma; however, no significant difference in disease-specific survival was noted (median survival, 2.8 years vs 3.0 years; 5-year survival, 37% vs 35%, respectively).

CONCLUSION

Sinonasal melanomas demonstrated aggressive morphologic features significantly more frequently than oral melanomas; however, prognosis remained similar in both groups.

Imaging of neoplasms of the paranasal sinuses

The assessment of sinonasal malignancies requires a multidisciplinary team approach. Advances in pretherapeutic imaging have significantly contributed to the management of sinonasal tumors. CT and MR imaging play complementary roles in the assessment and staging of these malignancies by determining the presence or absence of extension of disease into the skull base and its foramina, the orbit, and the intracranial compartment.

Misdiagnosis of olfactory neuroblastoma

OBJECT

Olfactory neuroblastoma (ON) is a rare neoplasm arising from the olfactory epithelium and found in the upper nasal cavity. The authors studied the frequency with which ON is misdiagnosed with other tumors of the paranasal sinuses such as neuroendocrine carcinoma (NEC), pituitary adenoma, melanoma, lymphoma, and sinonasal undifferentiated carcinoma (SNUC). Based on the belief that misdiagnosis commonly occurs, they emphasized the importance of establishing the correct diagnosis, because the treatment regimens and prognosis of these tumor types are often significantly different.

METHODS

Twelve consecutive patients in whom ON was diagnosed were referred to the Department of Neurosurgery at the M. D. Anderson Cancer Center between January 1998 and March 2000. Demographic data were collected, physical findings and mode of treatments were documented, and neuroimaging studies were assessed. Pathologists at the authors' institute reviewed the histological specimens. Only in two of 12 patients was the diagnosis of ON confirmed. Lesions in 10 patients were misdiagnosed; there were two cases of melanoma, three cases of NEC, three cases of pituitary adenoma, and two cases of SNUC. Eight of 10 patients in whom lesions were misdiagnosed required significant alteration in the initially proposed treatment plan.

CONCLUSIONS

Neurosurgeons should be acutely aware of the variety of neoplasms that occur in the paranasal region. The correct diagnosis should be ensured before initiating treatment to provide the optimum therapy and spare the patients from needless and potentially toxic treatment.

Primary mucosal malignant melanoma of the head and neck

INTRODUCTION

The relative rarity of mucosal melanomas of the head and neck (MMHN) has made analysis of treatment approaches difficult. Advances in diagnostic techniques and treatment interventions have had obvious impact on outcomes in cutaneous melanoma, but the effects on outcome in MMHN remain undefined. This study aims to assess the outcome and identify clinical and histologic prognostic indicators in a recent cohort of patients with MMHN treated at a single institution.

METHODS

The clinical records of 59 patients with the diagnosis of MMHN treated at Memorial Sloan-Kettering Cancer Center (MSKCC) between 1978 and 1998 were retrospectively reviewed. Pathologic material on each of these patients was prospectively reviewed by at least two pathologists (MP, KB, or AH) for confirmation of diagnosis and assessment of histologic variables. Survival was calculated by the Kaplan-Meier method. Clinical (patient demographics, tumor characteristics, and treatment) and histologic data (tumor thickness, melanosis, melanoma in situ, vascular invasion, and multifocality) were analyzed for impact on outcome by both univariate and multivariate analyses.

RESULTS

Thirty-five patients (59%) had sinonasal tumors (SNMM), whereas 24 (41%) had oral (ORMM) tumors. Forty-seven patients (79.6%) were staged as stage I, 8 (13.6%) as stage II, and 4 (6.8%) were classified as stage III. Regional lymphatic metastases at presentation were more frequent in ORMM compared with SNMM (25% vs 6%, p =.05). Surgery was used in all patients. Adjuvant radiation therapy was used more frequently in the SNMM group compared with the ORMM group (40% vs 17%, p =.04). The rates of local failure for ORMM and SNMM were 51% and 50%, nodal failure rates were 42% and 20%, and distant failure rates were 67% and 40%, respectively (p = NS). With a median follow-up of 20 months, the 5-year disease-specific survival rate was 44% (40% for ORMM vs 47% for SNMM, p = NS). Significant prognostic factors for disease-specific survival on univariate analysis included advanced clinical stage at presentation, tumor thickness greater than 5 mm, presence of vascular invasion, and development of nodal and distant metastases. On multivariate analysis, however, regional nodal failure lost significance.

CONCLUSIONS

Clinical stage at presentation, tumor thickness greater than 5 mm, vascular invasion on histologic studies, and development of distant failure are the only independent predictors of outcome in MMHN.

Melan-A as a useful diagnostic immunohistochemical stain for the diagnosis of primary sinonasal melanomas

BACKGROUND

Sinonasal melanomas are rare neoplasms whose diagnosis may require confirmatory immunohistochemical stains. S-100 protein and HMB-45, the stains most commonly used, have varying sensitivities and specificities. Melan-A, a more recent melanoma-specific marker, may prove helpful when S-100 protein and HMB-45 stains are negative or equivocal.

METHODS

Seven cases of sinonasal melanoma were assessed for reactivity with Melan-A, S-100 protein and HMB-45.

RESULTS

The study group consisted of two women and five men ages 40 to 83. Six of the neoplasms were strongly positive for S-100 protein. One case was negative for S-100 protein and HMB-45 but positive for Melan-A. HMB-45 staining varied between diffusely positive (three cases), focally positive (two cases), and negative (two cases). All cases were positive for Melan-A either diffusely (four cases) or focally (three cases).

CONCLUSION

Because Melan-A can be positive in cases that are S-100 protein or HMB-45 negative, it is a useful component in the immunohistochemical panel for the diagnosis of sinonasal melanomas.

Malignant melanoma of the sinonasal cavity: explanation of magnetic resonance signal intensities with histopathologic characteristics

PURPOSE

To evaluate the magnetic resonance (MR) findings of malignant melanoma of the sinonasal cavity and compare these findings with those of the histopathological examination.

MATERIALS AND METHODS

The MR images of 11 patients with malignant melanoma of the sinonasal cavity were retrospectively reviewed. Ten patients had primary malignant melanoma of the sinonasal cavity and one had a local recurrence. The imaging findings were evaluated with special attention given to the signal intensity of the tumor, internal characteristics, and growth pattern on MR. Signal intensity and enhancement patterns of the tumors were compared with the histopathological findings.

RESULTS

On T1-weighted image, 6 tumors were hyperintense (5 melanotic and one amelanotic melanoma), and 5 tumors were isointense or hypointense (4 amelanotic and one melanotic). On T2-weighted images, 2 amelanotic tumors showed hyperintensity, and 5 melanotic tumors showed hypointensity. Four tumors (one melanotic and 3 amelanotic) were isointense. Four of the 7 tumors with hyperintensity on T1-weighted images showed patchy, higher-signal intensity areas. In 3 of them, patchy areas of a higher degree of pigmentation were found on histopathological examination. There were multiple linear dark signal intensities on T2-weighted images and/or linear-enhancing areas on enhanced T1-weighted images within the masses in 5 of the 11 patients. These findings could be explained as intratumoral vessels in 4 tumors and fibrous septa in one tumor on histopathological examinations.

CONCLUSION

Malignant melanoma of the sinonasal cavity shows characteristic MR signal intensity, which is mainly attributable to the degree and distribution of melanin pigmentation, and partly attributable to hemorrhage within the mass. The linear, low-signal intensity on T2-weighted images or enhanced lines are intratumoral vessels or fibrous septa.

CD44 expression in sinonasal melanomas: is loss of isoform expression associated with advanced tumour stage?

The expression of the adhesion molecule CD44 was examined in 14 primary sinonasal melanomas (SMs), aggressive neoplasms with short survival times, as CD44 overexpression has been linked to poor survival in human cancers. Immunohistochemistry was performed on formalin-fixed, paraffin-embedded sections with CD44 isoform-specific monoclonal antibodies to the CD44 standard (s) and variant isoforms (v) v5 and v6. CD44s, v5, and v6 were strongly expressed in a membranous pattern in SM in situ, early invasive SM, and in uninvolved respiratory/squamous epithelium. In invasive SM, membranous CD44s expression was identified in a large proportion of melanoma cells. Membranous staining of CD44v5 and v6 was lost in invasive SM, independently of the histological subtype. Diffuse cytoplasmic staining was observed focally in invasive SM and loss of cytoplasmic expression of CD44v6 and v5 was associated with advanced tumour stage in the linear-by-linear association test (p = 0.042 and 0.066, respectively). CD44s may not be important for malignant transformation, as it is expressed in both benign and malignant melanocytes. Loss of membranous CD44 isoform expression in widely invasive SM suggests that loss of cellular adhesion facilitates matrix and vascular infiltration and dissemination of sinonasal melanoma cells.

Primary mucosal melanomas of the nasal cavity and paranasal sinuses. A clinicopathological analysis of 14 cases

We present 14 patients with primary sinonasal melanomas (SM) identified from 1984-1997 in our archives (11/14 lateral nose, 1/14 nasal septum, 2/14 paranasal sinuses; 8M/6F, mean age 67.7 years, range 39-88 years). Survival was poor (median 9 months) with death related to extensive local disease and/or widespread hematogenous metastases. The following histological subtypes were identified in descending order: amelanotic small blue cell, pleomorphic, epithelioid, spindle cell and myxoid. High mitotic rate and vascular invasion, absence of tumor-infiltrating lymphocytes and regression were features shared by all SM. Negative staining of B- and T-cell markers, LCA, neuroendocrine markers such as NSE, chromogranin and synaptophysin, and CK-negativity excluded olfactory neuroblastoma, small cell undifferentiated carcinoma, and lymphoma. S-100 protein was expressed in all SM, but demonstrated variable staining intensity with areas of complete negativity. HMB45 was strongly and uniformly (>80%) expressed in all undifferentiated small blue cell SM. The pigmented SM were predominantly HMB45-negative. The strong HMB45 staining in amelanotic small blue cell SM is explained by the reaction of HMB45 antibody with an oncofetal antigen found in immature melanosomes. In these poorly differentiated amelanotic malignant melanomas, antibody to HMB45 proved to be a superb diagnostic marker. We therefore strongly advocate the inclusion of HMB45 antibody in the panel of antibodies for initial work-up of undifferentiated mucosal neoplasms, since a negative S-100 stain in small biopsy material may result in incorrect classification of these neoplasms.

Malignant mucosal melanoma of the head and neck: review of the literature and report of 14 patients

BACKGROUND

Fortunately, primary malignant mucosal melanoma of the head and neck is a rare entity. A paucity of data elucidating the predictive factors as well as the unpredictable and aggressive biologic behavior of mucosal melanoma compound the vexing clinical situation. This review summarizes what the literature reveals about the epidemiology, patient survival, patterns of local recurrence, and local and distant metastasis of the disease. Over 1000 patients with this disease have been reported. Survivals at 5 and 10 years is 17% and 5%, respectively. Approximately 19% of patients present with lymph node metastasis and another 16% develop lymph node metastases after treatment, whereas 10% present with distant metastasis. Local metastasis does not affect survival; this is in sharp contrast with skin melanoma. Over 50% of patients experience local treatment failure, and salvage treatment is effective in only 25% of these cases. Local failure is the harbinger of distant metastases. Patients with nasal mucosal melanoma have a 31% 5-year survival rate, whereas sinus melanoma patients fare poorly, with a 0% rate of 5-year survival.

METHODS

The authors conducted a retrospective review of 14 patients with characteristics similar to those in the literature in terms of outcome.

RESULTS

The 5-year survival rate for these patients was 14%. Whole-body positron emission tomography was performed on 3 patients to detect metastatic disease. The patterns of local recurrence, distant metastasis, and survival for these patients were compared with the same data for patients described in the literature.

CONCLUSIONS

Surgery appears to have the greatest efficacy in the management of mucosal melanoma, although radiation therapy may play an increasingly important role in the future.

Melanoma botryoides: a distinctive myxoid pattern of sino-nasal malignant melanoma

Two primary sino-nasal melanomas are presented which were characterized by their botryoid growth pattern and myxoid stroma. These polypoid tumours contained small amounts of melanin and only focal areas of epithelioid cells. An in situ component was present in both of the tumours. Malignant melanoma should be considered when confronted by a myxoid tumour (with or without melanin) in the sino-nasal region. These tumours are widely infiltrative, and there is no evidence to suggest that they will behave any differently from conventional, non-botryoid, non-myxoid sino-nasal melanomas.

Rare variants of malignant melanoma

The personal experience with 5 rare types of malignant melanoma is reviewed to point out some of the practical problems in the diagnosis and management of these tumors. The rare forms discussed are conjunctival, nasal, oral, vulvar, and penile melanomas. All pigmented lesions in the oral cavity, but not the penis or vulva, should be prophylactically excised as lesions in the mouth have a higher malignant potential. Local excision of all 5 forms of primary melanomas, no matter how locally advanced they may be, is the sole treatment. Nevertheless, anatomic constraints often preclude surgery with generous margins and consequently local recurrence, particularly for conjunctival, nasal, and oral primary lesions, is usually the major first failure in treatment. Lymph node dissection is only performed if the regional nodes are palpable at the time of first presentation. Elective lymph node dissections are not performed since the patients are often elderly, the lymphatic drainage is usually ambiguous or multiple, and the disease tends to spread hematogenously rather than lymphatically. Surgery still remains the cornerstone of treatment for these rare forms of melanoma but prognosis is very poor since surgery is often a palliative rather than a curative measure. Improved survival may depend on identifying more effective chemotherapeutic and immunologic agents.