Anorectal Malignant Melanoma

Anorectal Malignant Melanoma Post- Hemorrhoidectomy

Anorectal malignant melanoma, a rare and aggressive tumor, lacks specific symptoms and frequently presents diagnostic challenges due to its similarity to benign anorectal conditions. This case report describes the diagnostic and treatment process of incidentally discovered anorectal malignant melanoma post-hemorrhoidectomy, guided by the existing literature.

[Anorectal melanoma : Update on clinical presentation, diagnosis and treatment]

Anorectal melanomas are a rare malignant type of cancer and pose a diagnostic challenge due to their hidden anatomical location. They are associated with nonspecific clinical symptoms and are therefore often misinterpreted as benign disease. The result is delayed diagnosis in the locally advanced or metastasized stage and an unfavorable prognosis. Given the overall low incidence of the tumor, no consensus guidelines for diagnosis or therapy are established either internationally or nationally at present. The present work intends to provide a comprehensive overview of the clinical aspects, diagnostics, and therapeutic approaches of anorectal melanoma based on the currently available literature.

Primary anorectal amelanotic melanoma with liver, lungs and lymph nodal metastases

Anorectal melanoma (ARM) is an exceedingly rare and very aggressive malignancy. It originates from the melanocytic cells in the anorectal mucosa, which produces melanin. Other mucosal melanomas commonly found in the mucosa of the oral cavity, vulvovaginal, pharynx and urinary tract. Patients usually present with bleeding per rectum, perianal pain and difficulty in defaecation. Distinction of primary anorectal melanoma from other tumours of this region is difficult because of the lack of common imaging features. MRI is the modality of choice for its better tissue characterisation and resolution. There is no standard treatment protocol available mainly due to scarcity of data. Surgery is the mainstay therapy. Herein we present a case of a male patient in his 30s who presented with rectal bleeding and perianal pain. Haematological analysis revealed normocytic normochromic anaemia. MRI detected a mass lesion in the anorectal region. Contrast enhanced CT revealed multiple metastases in the liver, lungs, periportal, mesorectal and inguinal lymph nodes. The diagnosis of the ulcerated anorectal melanoma was established on histopathological examination. The patient underwent abdominoperineal resection (APR) followed by chemotherapy. Afterward the patient presented to the emergency room with respiratory distress for which he was on ventilator support. Sadly, the patient died after four days.

Primitive rectal melanoma: A rare case report

Mucosal melanoma is a rare subtype of melanoma distinct from the cutaneous type in its clinical and biological aspects, requiring different therapeutical management. Anorectal melanomas represent less than 1% of anorectal cancers and 0.3% of malignant melanomas, and they are by far the most studied type. Proctologic examination, colonoscopy, and biopsy can establish a correct diagnosis. Imaging techniques, especially MRI can show some characteristic features, but it is essentially performed for extension assessment. We report the case of a 63-year-old man who consulted for rectal bleeding. The proctological examination found a brownish ulcerative-vegetating tumor of 3 cm in diameter located 3 cm from the anal rim. The endoscopic examination revealed a predominance of ulcerative budding lesions and the biopsy specimen confirmed a rectal melanoma. The extension assessment, based on a computed tomography scan and MRI did not show locoregional or distant metastases. Radiotherapy and abdominoperineal resection with pelvic node dissection was the treatment of choice with good evolution.

Metastatic melanoma and rare melanoma variants: a review

The histopathological diagnosis of melanoma is fraught with potential pitfalls. In the setting of cutaneous metastatic melanoma, it is important to recognise the various histological patterns that can be encountered from the more common to the rare, including epidermotropic, folliculotropic, naevoid, and blue naevus-like. In addition, melanoma is notorious for phenotypic plasticity. Thus, there are many different subtypes and cytomorphological variations that can be difficult to recognise as melanoma, particularly in the recurrent or metastatic setting. Select melanoma variants including primary dermal, clear cell, plasmacytoid, signet ring cell, small cell, myxoid, rhabdoid, and dedifferentiated melanoma will be discussed, in addition to composite melanocytic neoplasms. This review is intended to remind the practitioner of key concepts of metastatic disease and select rare melanoma variants, while providing practical guidelines for accurate diagnosis.

Anal intraepithelial neoplasia: a review of terminology, differential diagnoses, and patient management

Despite the knowledge of etiological association with high-risk human papilloma viruses and high-risk patient cohorts, the incidence of anal squamous cell carcinoma has continued to rise. The known precursor lesion (in particular, high-grade squamous intraepithelial lesion) makes it amenable to screening and surveillance strategies. However, the diagnosis of anal intraepithelial neoplasia suffers from interpretation challenges leading to high interobserver variability, along with numerous differential diagnoses and lingering terminology issues. Proper treatment of anal lesions requires accurate diagnosis, and while a variety of modalities are available for treatment, the rate of recurrence remains high and each modality has its own set of side effects and complications. The aim of this review article is to outline the diagnostic considerations and provide practical tips for diagnosing anal squamous intraepithelial lesions.

Metastatic Anorectal Melanoma Presenting as Seizures: An Infrequent Culprit

Anorectal malignant melanoma is a rare culprit of malignancies in the anorectal region. With a presentation that mimics the vastly more common colorectal tumours, clinical misdiagnosis and diagnostic delays often occur, contributing to a dismal prognosis. The authors report a case of metastatic anorectal malignant melanoma presenting as seizures. Though our standard diagnostic pathway for suspected anorectal malignancies was followed, and despite the patient having computerized tomography (CT) of the head earlier, this presentation nonetheless led to a prolongation of time needed to reach histological diagnosis and delay in commencing definitive treatment. It also highlights the paucity of research into the pathophysiology and management of this infrequent but aggressive disease, and the need for raising awareness about this condition to the medical community so that it is considered as a plausible differential diagnosis from the outset and diagnostic pathways adjusted accordingly.

Clinicopathological profile and outcomes of anorectal melanoma from a tertiary care center in India

Background:

Anorectal melanoma (AM) is a rare subtype of melanoma.

Aim:

To study the clinic–pathologic features and outcomes in patients with AM.

Materials & methods:

Clinical, pathologic findings and outcomes of patients with AM were recorded.

Results:

Twenty-seven patients with AM were identified with median age of 57 years. Most patients presented in stage III (44.4%). Lymph node involvement was seen in 70.4%. The response to chemotherapy and immunotherapy was 16.6 and 25.0%, respectively. At a median follow up of 11 months, median overall survival was 30 months. Ballantine stage 3 and weight loss at presentation were predictors of poor survival.

Conclusion:

AM presents at an advanced stage with lymph node and distant metastasis.

Anorectal melanoma is a rare subset of melanoma presenting at an advanced stage with lymph node and distant metastasis. Early disease is managed surgically; however, optimal treatment of advanced disease is unclear. The stage at diagnosis is the most important prognostic factor. Prognosis is poor, but with the advent of targeted therapy and immunotherapy, the outcomes are improving.

OUP accepted manuscript

Background

Materials and Methods

Results

Conclusions

Naturally occurring and synthetic peptides: Efficient tyrosinase inhibitors

Tyrosinase is a copper-containing enzyme involved in the biosynthesis of melanin pigment, which is the most important photo protective agent against skin photo carcinogenesis. Excess production of melanin causes hyperpigmentation leading to undesired browning in human skin, fruits, and vegetable as well as plant-derived foods. Moreover, the role of tyrosinase in the onset and progression of various diseases such as cancers, Alzheimer's, and Parkinson diseases has been well documented in the literature. In this respect, tyrosinase inhibitors have been in the center of attention particularly as the efficient skin whitening agents. Among a wide range of compounds possessing anti-tyrosinase activity, peptides both natural and synthetic derivatives have attracted attention due to high potency and safety.

Anal Melanoma: A Case Report of a Rare and Lethal Malignancy in a Suburban Nigerian Teaching Hospital

The aim of this report is to highlight the challenges involved in the diagnosis and treatment of anal melanoma in a tertiary hospital in Nigeria. It is a case report of an 84-year-old man who was managed for anal malignant melanoma. Despite inadequate investigative tools and less radical surgical treatment, the survival period of the index patient was comparable to the median survival quoted in the literature. Despite its rarity, mucosal melanomas also occur in the tropics. Prompt diagnosis, adequate imaging, and standardized treatment may improve its outlook in the nearest future.

Anorectal melanoma – histopathological and immunohistochemical features and treatment

Anorectal melanomas should be characterized by location (anal, rectal and anorectal), color, size, shape and mobility and microscopically, by melanocyte subtypes, grade of melanin pigmentation, junctional changes in the squamous epithelium, atypical mitotic index, cellular atypia, inflammatory infiltrate, vascular and perineural invasion, sentinel lymph node, and anorectal parietal penetration. Anorectal melanomas must be staged by American Joint Committee on Cancer (AJCC) and/or TNM Classification of Malignant Tumours (TNM) criteria. As melanocytes can present with several shapes, sometimes the differential diagnosis with other tumors in this region may be difficult. Because of this, immunohistochemistry is mandatory to attain a precise diagnosis. This study is a report of 14 patients with anorectal melanoma, in whom histological examinations were remade and immunohistochemistry was performed with several markers for melanocytes and for other tumor cells of the anorectal region, properly establishing the diagnosis. The most rational surgery is the extended local resection, when the disease is restricted to the area or the abdominoperineal resection to advanced lesions. Regardless of the technique used, the results are always poor. The authors deny any efficacy of current radio and/or chemotherapy as part of treatment of anorectal melanoma. Target-therapy for metastatic disease has been considered a good strategy, but the results are still inconclusive.

Clinical evidence, diagnostic approach and challenging therapeutic modalities for malignant melanoma of the anorectum

Primary anorectal malignant melanoma (ARMM) is a rare, aggressive tumour that accounts for approximately 1.2% of all melanomas. This rare entity represents less than 5% of anorectal malignant tumours and 0.05-1% of all malignant colorectal neoplasms. The incidence increases with age while there is a higher prevalence in Caucasians. ARMM is often asymptomatic or presents with no disease-specific evidence so that it can mimic other rectal disorders, malignant or benign. Colonoscopy is obligatory as a diagnosing mean for ARMM. Furthermore, endoscopic ultrasonography, computed tomography and magnetic resonance imaging can be utilized for the evaluation of tumour infiltration and lymph node metastases. Moreover, diagnostic establishment of ARMM requires an undeniable demonstration of essential melanocytic features in histology and immunohistochemistry. Even though the standard of treatment remains surgical resection, the choice between wide local excision and abdomino-perineal resection is still controversial. Recently, there have been recommendations regarding new techniques which could be utilized for the surgical treatment of ARMM. Newer treatments that have been proposed such as immune-checkpoint inhibitors and targeted therapies need further validation. A multicenter study would allow clarification of the most appropriate therapeutic strategy for this uncommon nosological entity.

An Unusual Case of Human Papillomavirus-Related Anorectal Adenocarcinoma With Progression to Perianal Paget's Disease

Primary adenocarcinoma of the anorectum, compared with squamous cell carcinoma, is a rarer and more aggressive malignant neoplasm. Infection with human papillomavirus (HPV) has been identified as a causal agent in a variety of tumors, including those of the cervix, head and neck, and anogenital region, especially squamous cell carcinoma. However, the relationship between HPV and anorectal adenocarcinoma has not been well studied. In this article, we report an HPV-related anorectal adenocarcinoma arising in a tubulovillous adenoma in a 76 years old female who presented initially with lower gastrointestinal bleeding. The carcinoma cells were positive for cytokeratin 7 and p16 by immunohistochemistry. High-risk HPV RNA in situ hybridization was positive. A follow-up examination of the anal area showed perianal plaques. Histologically, the excision of the perianal lesion showed intraepithelial infiltration by sheets and clusters of large atypical neoplastic cells. The neoplastic cells showed the same immunoprofile compared with the anorectal adenocarcinoma with p16 and high-risk HPV positivity. The findings are consistent with extramammary perianal Paget's disease secondary to anorectal adenocarcinoma. HPV-related adenocarcinoma in the anorectum is a newly recognized entity and was previously considered clinically indolent. Our case uniquely exhibits adenoma-carcinoma-perianal Paget's disease sequence, which has not been reported before. Our findings suggest that evaluation of the patient's lower genital tract for any HPV-associated lesions and long-term follow-up are required to monitor the disease progression in this type of malignancy.

Primary anorectal malignant melanoma with laparoscopic abdominoperineal resection: a case study and review of the relevant literature

ARMM is a disease with a poor prognosis. ARMM is often diagnosed at an advanced stage, and the 5-year survival rate of ARMM is < 20%. Although the number of case reports on ARMM is gradually increasing, the optimal treatment strategy for ARMM remains controversial. We report the case of an 81-year-old woman who had experienced bloody stool for 6 months before her diagnosis and who had been initially diagnosed with hemorrhoids. The pathological diagnosis of a biopsy specimen was malignant melanoma. Other examinations showed no evidence of lymph node or distant metastasis. Based on these results, laparoscopic abdominoperineal resection was performed. Three months later on her first follow-up examination, distant metastasis to the lung and liver was detected. Immunotherapy using Nivolumab was initiated to treat the recurrent disease. We reviewed the characteristics of a total of 1834 ARMM patients described in previous reports on ARMM for which the full text was available on PubMed. We experienced a case of ARMM. The prognosis of ARMM is still poor, regardless of the surgical procedure. Previous studies and our case report suggest that systemic therapy, such as immunotherapy using an anti-PD-1 ligand may be more important than reinforcement of local control for improving the prognosis of ARMM patients.

Perianal Paget's disease: a clinicopathological and immunohistochemical study of 13 cases

BACKGROUND

Perianal Paget's disease (PPD) is rare and mostly described in clinical literature as case reports or small series.

METHODS

We investigated the clinicopathologic and immunohistochemical features of PPD in a total of 13 cases retrieved from multiple academic institutions.

RESULTS

The median age at diagnosis was 75 (range 50-86) years. Males were predominant with a male to female ratio of 2.25:1. Four (30.8%) cases were classified as primary PPD due to lack of synchronous or metachronous underlying malignancies, while nine (69.2%) were classified as secondary PPD with concurrent invasive adenocarcinoma (n = 8) or tubular adenoma with high-grade dysplasia (n = 1). Immunohistochemically, there is no differential expression of CK7 or CK20 in Paget's cells between primary and secondary PPD; however, GCDFP-15 was only positive in primary PPD (3/3 vs. 0/6, P = 0.012), while CDX2 was only positive in secondary PPD (0/3 vs. 7/7, P = 0.008), suggesting different cell origin. All patients received local surgical resection with or without adjuvant therapy. After a median follow-up of 47 months, one patient with secondary PPD (7.7%) died of disease progression from underlying adenocarcinoma.

CONCLUSIONS

PPD occurs in elderly patients with male predominance and is frequently associated with underlying malignancies. Differential expression of CDX2 and GCDFP-15 may help distinguishing primary vs. secondary PPD, which is important for management as the presence of an underlying malignancy impacts clinical course and prognosis. Surgical excision remains the major treatment strategy for PPD. Long-term follow-up is required to monitor the disease recurrence and metastasis.

Malignant melanoma of the rectum presenting as cloacogenic polyp: a case report

Mucosal malignant melanomas are uncommon. It is rare for a primary mucosal melanoma to occur in the anorectal region. Anorectal polypoid mucosal prolapse however, is a relatively common condition. We report a case of malignant melanoma presenting as mucosal prolapse and inducing changes similar to inflammatory cloacogenic polyp.

Anorectal Malignant Melanoma: Retrospective Analysis of Six Patients and Review of the Literature

Malignant melanomas are rare aggressive tumours originating from the pigment-producing melanocytes. In our study, a review of the literature and a retrospective analysis of patients undergoing surgery at our clinic due to anorectal malignant melanoma were performed. The information of 6 patients undergoing surgery in our clinic due to anorectal malignant melanoma between January 2010 and January 2018 was retrieved retrospectively. The patients were assessed regarding demographic data, physical examination and imaging findings, the surgical method performed, postoperative complication, histopathological findings, oncological treatment and follow-up results. Four of the patients were female and 2 were male and the mean age was 61.6 (46–83) years. Two patients (33%) had liver metastases at the time of initial presentation. Abdominoperineal resection (APR) was performed in all patients 3 with laparoscopic method. The mean length of hospital stay was recorded to be 6.5 ± 1 days (5–12 days). Adjuvant chemotherapy and radiotherapy were administered in all patients. Also, interferon treatment was administered in one patient additionally. During the follow-up, 4 patients died due to extensive metastatic disease determined approximately in the 13th month. Two patients with regular follow-up are well and free of disease and their mean postoperative lifetime has been determined to be 12.5 months (6–26 months). Anorectal malignant melanomas (ARMM) are rare but aggressive tumours. The treatment should be focused on minimizing morbidity and maximizing the quality of life and function while removing the gross tumour.

Morphologic and Immunohistochemical Characteristics of Anorectal Melanoma

Anorectal melanoma is a rare aggressive disease. Due to its rarity and considerable histologic and immunohistochemical variabilities, misdiagnosis as lymphoma, carcinoma, sarcoma, and/or gastrointestinal stromal tumor is not uncommon, particularly in amelanotic cases. We reviewed histologic features and immunohistochemical stains of 19 anorectal melanoma cases. Histopathologic features were evaluated including junctional activity, melanin pigment, and morphologic features. Immunohistochemical stains were performed using Sox10, S100 protein, HMB-45, melan-A, CD56, and cytokeratins. Epithelioid histopathologic morphology was observed in 63.2% of the cases followed by 47.4% of the cases with spindle-cell, 26.3% with lymphoma-like, and 26.3% with pleomorphic morphologies. Junctional melanocytic activity was seen in almost half of the cases. Melanin pigment was absent (amelanotic) in nearly 40% of the cases. Immunohistochemically, diffuse positive expression of Sox10, S100 protein, melan-A, and HMB-45 was seen in 100%, 40%, 53.3%, and 38.5% of the cases, respectively. Cytokeratins were negative and CD56 was positive in 2 cases. These findings indicate that anorectal melanomas often show one or combined histolopathologic features without presence of melanin pigment and absence of junctional melanocytic activity. Anorectal melanoma should be kept in mind in the differential diagnosis of malignant neoplasms of anorectal region with epithelioid, spindle-cell, lymphoma-like, and pleomorphic morphologies. Sox10 immunohistochemistry stain can be used as a first-line screening tool to avoid extensive or unnecessary workups and/or potential misdiagnosis.

Benign and malignant tumors of the rectum and perirectal region

Although most rectal masses are histologically characterized as adenocarcinomas, the rectum and perirectal region can be affected by a wide variety of tumors and tumor-like conditions that can mimic the symptoms caused by rectal adenocarcinoma, including mucosal or submucosal rectal tumors such as lymphoma, gastrointestinal stromal tumor, leiomyosarcoma, neuroendocrine tumor, hemangioma, and melanoma, as well as tumors of the perirectal region such as developmental cyst, neurogenic tumor, osseous tumor, and other miscellaneous conditions. As a group, tumors of the rectum are considerably different from the group of tumors that arise in the perirectal region: they are most often neoplastic, symptomatic, and malignant, whereas tumors arising in the perirectal region are most commonly congenital, asymptomatic, and benign. Proctoscopy with biopsy is the most important method for the diagnosis of rectal tumors, but this procedure cannot determine the precise intramural extension of a rectal tumor and cannot accurately distinguish submucosal and intramural tumors from extramural tumors. Cross-sectional imaging, especially transrectal ultrasound and magnetic resonance imaging, allows evaluation of the entire bowel wall thickness and the perirectal tissues, helping further characterize these tumors. Recognition of the existence of these masses and their key clinical and imaging features is crucial for clinicians to accurately diagnose and appropriately manage these conditions.

Tumours and inflammatory lesions of the anal canal and perianal skin revisited: an update and practical approach

Tumours of the anal and perianal region are relatively rare, and clinically often interpreted as innocuous lesions, leading to frequent delays in diagnosis and adequate treatment. Although squamous cell neoplasia represents the most common entity encountered in this anatomically complex area, many conditions, both neoplastic and inflammatory, may occur. Adding to the challenge of correct diagnosis and patient management, recent years have seen major updates in the terminology of squamous cell neoplasia, created to reflect advances in our understanding of the role of human papilloma virus and unify previous terminologies used for different sites in the anogenital tract. However, squamous cell neoplasia in the anal canal and perianal region may differ in terms of histology, biological behaviour, staging and treatment. The aim of this review is to present an overview of neoplastic and non-neoplastic lesions that may be seen in this area, an update on important developments and terminology, potential pitfalls that may be encountered in routine pathology practice and a practical approach on how to resolve these issues.

Primary anorectal melanoma on FDG PET/CT

Primary anorectal melanoma is an extremely rare, aggressive malignancy with a poor prognosis. A 76-year-old man with a 2-month history of rectal bleeding, anal pain, and tenesmus was referred for an F-FDG PET/CT examination, which revealed an abnormal focal FDG uptake on the lower rectum with multiple other intense FDG-avid regions in locoregional pelvic lymph nodes, bones, liver, and lung. It was highly suggestive of malignancy, and a provisional diagnosis of advanced rectal carcinoma was made. However, a following tissue biopsy of the lesion on the lower rectum performed by colonoscopy histopathologically indicated primary anorectal melanoma.

Update on primary mucosal melanoma

Mucosal melanomas are aggressive cancers of mucosal surfaces with clinical and pathologic characteristics distinct from cutaneous melanomas, warranting different staging systems and treatment approaches. Surgical resection is performed frequently for the primary tumor, although the utility of lymph node surgery and radiation therapy is not established. Therapies targeted against C-KIT activating mutations, identified in many mucosal melanomas, are emerging as promising treatments.

Primary anorectal melanoma

Primary malignant melanoma of the anus and rectum is a rare and aggressive neoplasm that tends to invade locally and metastasize early in the course of the disease. It is often misdiagnosed as hemorrhoids or as one of the other benign anorectal conditions and is thus linked to an overall poor prognosis and a 5-year survival rate of less than 20%. Optimal treatment is still controversial, and current evidence does not show any preferential survival benefit from abdominoperineal resection over wide local excision. Chemotherapy or radiotherapy may be used for advanced disease. We report a 71-year-old female presenting with painful bowel movements and blood in stools. She was eventually found to have a mass arising from the anorectal junction with regional lymph node involvement. The patient underwent an abdominoperineal resection and is currently scheduled for chemotherapy.

Primary anorectal melanoma: A case report with extended follow-up

Background:

Anorectal melanoma is a rare and aggressive disease. The mainstay of treatment is usually surgical with curative or palliative intent, since radio- and chemotherapy do not really improve the outcome. The poor prognosis is attributable to delay in diagnosis and its inherent biologic aggressiveness.

Case Report:

We present a case of anorectal melanoma in a 68-year-old man who underwent solely abdominoperineal amputation and was doing well 30 months after surgery, without any evidence of recurrent disease.

Conclusions:

Treatment of anorectal melanoma should be by the least morbid means possible. Surgical procedure that can achieve a complete local excision and respect the functional aspects and quality of life of the patient remains the best therapeutic approach. No systemic regimen for metastatic anorectal melanoma is considered standard of care.

KIT gene exon 11 mutations in canine malignant melanoma

The proto-oncogene KIT encodes a receptor tyrosine kinase which has been shown to be upregulated in canine melanomas. KIT mutations lead to constitutive phosphorylation and activation of KIT in the absence of ligand binding. The presence of KIT mutations and KIT protein expression was examined in a cohort of 49 dogs with canine malignant melanoma. An exon 11 synonymous nucleotide 1743C→T mutation was identified in five cases in which one also harbored a L579P mutation. Tumors that harbored the KIT exon 11 mutation(s) correlated significantly with disease recurrence (P = 0.05). All 36 melanomas available for immunohistochemical analysis showed either weak (16 cases, 44.4%) or strong (20 cases, 55.6%) expression of the KIT protein. The five KIT mutation carriers were all strongly positive for KIT by immunohistochemical staining. These findings suggest that a subset of canine malignant melanomas harbors a KIT exon 11 mutation.

Expression of Sox10 and c-kit in sinonasal mucosal melanomas arising in the Chinese population

Sinonasal mucosal melanomas (SNMM) of the head and neck regions are rare and aggressive malignancies. Although they can affect patients of any ethnicity, they are more numerous in Chinese patients. The diagnosis and treatment of these tumors can be challenging. Recent studies have reported that Sox10 is a sensitive melanocytic marker for cutaneous melanoma (Nonaka et al. in Am J Surg Pathol 32:1291-1298, 2008). In addition, a CD117 (c-kit) gene mutation has been identified in cutaneous melanomas, indicating that there may be potential therapeutic benefits of tyrosine kinase inhibitors, such as Imatinib. The purpose of this study was to detect and test the immunohistochemical expression of Sox10 and c-kit in mucosal melanomas (MM) arising in the nasal cavities of Chinese patients. Twenty eight patients with mucosal melanomas of the nasal cavity were treated in two major hospitals in China. All cases had been locally diagnosed as primary SNMM. We confirmed all diagnoses with positive immunohistochemical stains for S100 and HMB-45. Additionally, automated immunohistochemistry was performed using a goat polyclonal Sox10 antibody and a monoclonal c-kit antibody counterstained using a standard avidin-biotin complex method. Immunohistochemical positive expression of Sox10 was defined by nuclear stain; and positivity for c-kit resulted in a distinct membranous staining. The extent of nuclear positivity for Sox10 and membranous stain for c-kit was graded by 4 board certified pathologists as follows: 1+, 1-25 % of positive tumor cells; 2+, 25-50 %; 3+, 50-75 %; and 4+, ≥75 %. Sox10 nuclear expression was found in all cases (100 %), with 4+ staining in 26 out of 28 cases (92.8 %) and 3+ staining in two cases with (7.1 %). The overall positivity for S100 staining was 23 out of 28 (82.1 %), with 1+ staining in 10 cases, 2+ staining in 6 cases, 3+ staining in 7 cases, and no staining in 5 cases. The sensitivity and intensity of Sox10 immunohistochemistry were both higher than with S100 immunohistochemistry. Immunopositivity of membranous stain for c-kit (CD117) was seen in 24 out of 28 cases (85.7 %), including 6 tumors that were 4+, eight that were 3+, six that were 2+, and four that showed 1+ staining. Our results demonstrate that Sox10 is a sensitive marker for SNMM and it may possess diagnostic value in addition to that of S100 protein. The expression of c-kit in the majority of MMs suggests that it may be useful in the assessment of these tumors for potential treatment with tyrosine kinase inhibitors.

Mucosal melanomas of the head and neck: new aspects of the clinical outcome, molecular pathology, and treatment with c-kit inhibitors

Approximately 50% of mucosal melanomas affect the head and neck region representing approximately 9% of all malignant head and neck tumors. The pathogenesis of this disease is unknown. Mucosal melanomas are characterized by an aggressive biological behavior, leading to a 5-year survival rate of less than 25%. Data for this review were identified by searches of Medline, Current Contents, PubMed, and references from relevant articles using the terms 'mucosal melanoma,' 'head and neck melanoma,' 'c-kit mutation in melanoma,' and 'c-kit inhibitors'. Therapy aims for the complete surgical excision of the primary tumor, whereas sentinel node biopsy is not established and present data do not support the addition of radiotherapy. Mutilating operations of larger tumors should be avoided, as they do not inhibit the frequent development of distant metastasis. C-kit mutations and amplifications are found in approximately 15-30% of mucosal and acral-lentiginous melanomas. Therefore, the use of so-called targeted therapies addressing molecular structures in mucosal melanomas seem to represent new promising treatment tools. In this study, we review the literature regarding epidemiology, molecular pathology, and therapy of mucosal melanomas of the head and neck emphasizing c-kit protein inhibiting treatment modalities for tumors carrying c-kit mutations.

c-kit gene mutation and CD117 expression in human anorectal melanomas

c-kit and BRAF mutations play an important role during the pathogenesis of melanoma. The subtypes of melanomas arising from different parts of the body have variable c-kit or BRAF mutation frequencies. Few studies in the literature have examined c-kit and BRAF mutation status in melanomas that occur in the anus and rectum. In this study, we analyzed 40 cases of anorectal melanoma for c-kit and BRAF mutations by DNA sequencing using paraffin-embedded tissues. c-kit Mutations were detected in exons 9, 11, 13, and 17. CD117 expression in tumor cells was analyzed by immunohistochemistry. Our study showed that a c-kit mutation was found in 7 of the 40 cases of anorectal melanoma. CD117 expression was detected in 16 of the 40 cases, and 3 of these 16 cases also had c-kit mutations. Mutations in BRAF were also identified in 2 patients. These results indicate that a subset of anorectal melanomas have activating c-kit mutations, which suggests that kinase inhibitors such as imatinib may be used to treat this subset of melanoma patients. In addition, our results show that c-kit mutations do not correlate with CD117 expression.

Primary retroperitoneal malignant melanoma: A case report

Primary malignant melanoma occurring at an extra cutaneous site is rare. A case of primary malignant melanoma located in the retroperitoneum of an 18-year-old female is presented in this study. Histopathological examination of the tissue biopsies at laparotomy with immunohistochemical stains confirmed a diagnosis of malignant melanoma. Further extensive clinical and radiological investigations proved the retroperitoneum to be the primary site.

Anorectal malignant melanomas: experience of Uludag University

Anorectal melanomas represent a group of mucosal melanomas with unknown etiology and poor prognosis. The lesions can be misdiagnosed as hemorrhoids during clinical examination. We reviewed the morphological and clinical features of 14 anorectal melanomas, and discuss the treatment modalities of this entity. Fourteen patients who were diagnosed with anorectal malignant melanoma between 1997 and 2004 were evaluated with regard to age, sex, size, morphology, lymph node or distant metastasis, treatment modality and survival. Eight patients were female and six were male, and their mean age was 58 years. The size of melanoma ranged from 3 cm to 8 cm. Pathological evaluation revealed epithelioid and spindle cell type tumor in seven and two patients, respectively, whereas, in the remaining seven patients, the tumor was composed of both types. Pigmentation was apparent in all tumors. There was lymph node metastasis in 11 patients and distant metastasis in all patients. Eleven patients underwent abdominoperineal resection and three were treated by local excision. Mean survival was 8.7 months. Prognosis of anorectal melanoma remains poor. Awareness of the diverse clinicopathological features of these lesions, both on the part of the clinicians and pathologists, is crucial for their early detection and proper treatment.

Treatment and outcomes of anorectal melanoma

INTRODUCTION

anorectal melanoma is an uncommon disease constituting less than 3% of all melanomas. Due to its rarity, there are a lack of randomized control trials regarding appropriate management and current evidence is based mainly on retrospective studies.

METHODS

in view of the controversial surgical treatment of anorectal melanoma, we review the most published literature in an attempt to elucidate its typical clinical features along with current thinking with respect to management approaches to this aggressive disease. Using the keywords "anorectal" and "malignant melanoma", a medline search of all articles in English was performed and the relevant articles procured. Additional references were retrieved by cross reference from key articles.

RESULTS

anorectal melanoma affects the elderly with a slight preponderance for females. It commonly presents disguised as benign disease with local bleeding or suspicion for haemorrhoidal disease. There is no convincing evidence to indicate that radical resection of primary anorectal melanoma is associated with improvement in local control or survival, and local excision is an acceptable treatment option.

CONCLUSION

optimum management depends on several factors and the therapeutic goals should be to lengthen survival and preserve quality-of-life. Given that wide local excision is a more limited intervention with comparable survival it should be considered as the initial treatment choice. Unfortunately prognosis for patients with this disease remains poor despite choice of treatment strategy with overall five year disease-free survival less than twenty percent in most studies.

Correlation between KIT expression and KIT mutation in melanoma: a study of 173 cases with emphasis on the acral-lentiginous/mucosal type

The role of immunohistochemistry in the assessment of KIT status in melanomas, especially acral lentiginous/mucosal, is not well established. Although the reported prevalence of KIT mutations in acral lentiginous/mucosal melanomas is relatively low, detection of mutations in KIT can have profound therapeutic implications. We evaluated the efficacy of immunohistochemistry to predict mutations in KIT. One hundred seventy-three tumors, comprising primary and metastatic melanomas (141 acral lentiginous/mucosal, 5 nodular, 4 lentigo maligna, 3 superficial spreading, 2 uveal, 1 melanoma of soft parts, 8 metastases from unclassified primaries, and 9 metastases from unknown primaries) were studied. Immunohistochemical expression of KIT using an anti-CD117 antibody and KIT mutational analysis by gene sequencing of exons 11, 13, and 17 were performed. Eighty-one percent of acral lentiginous/mucosal melanomas, primary and metastatic, showed KIT expression by at least 5% of the tumor cells. The overall frequency of activating KIT gene mutations in acral lentiginous/mucosal melanomas was 15% (14 out of 91 cases), being the L576P mutation in exon 11 the most frequently detected (4 of 14 cases). Cases showing less than 10% positive tumor cells were negative for KIT mutations. Eighty-two percent (12 of 14) of cases positive for KIT mutation showed KIT expression in more than 50% of the cells. An association between immunohistochemical expression of KIT and mutation status was found (P=0.007). Immunohistochemical expression of KIT in less than 10% of the cells of the invasive component of acral lentiginous/mucosal melanomas appears to be a strong negative predictor of KIT mutation and therefore can potentially be used to triage cases for additional KIT genotyping.

A renal mass in a patient with melanoma

A 61-year-old man presented to the emergency room with significant weight loss. Laboratory analysis revealed elevations in blood urea nitrogen, creatinine, and white blood cell count. Computed tomography imaging showed a large, infiltrative mass in the right renal vein, with metastasis to the brain. Biopsy of soft tissue mass and kidney revealed positive staining for malignant melanoma. Malignant melanoma to the kidney is extremely rare, and imaging modalities alone cannot differentiate neoplasms in the kidney. It is therefore necessary to use specific immunocytochemical staining along with imaging modalities to make a specific diagnosis when the primary origin of the tumor is unknown.

Primary Small Cell Malignant Melanoma of the Rectum: Case Report of a Very Rare Tumor

Rectal/anorectal malignant melanomas are highly aggressive tumors with a poor prognosis and low 5-year survival rate. They are also very rare. Of the well-known histological variants of malignant melanoma, the small cell subtype is also very uncommon; consequently, small cell anorectal malignant melanoma is an exceedingly rare occurrence. In this article, the authors provide a detailed clinicopathological description of small cell malignant melanoma of the rectum, documenting clinical, histological, immunohistochemical, and ultrastructural features, to add to the sparse references on this tumor in the literature. The patient was a 53-year-old woman with a mass 2 cm from the anus, which was surgically removed. In histological sections, the tumor was a small cell malignant melanoma, with a tumor cell diameter of 7.6+/-1.0 microm, and a range of 5.5-10.7 microm (N = 100). Tumor cells were positive for S-100 protein and HMB-45 and contained sparse but unambiguous type II melanosomes. This article is one of the few detailed clinicopathological documentations of a small cell malignant melanoma of the rectum (anorectum) and the first to have the diagnosis confirmed ultrastructurally by the identification of melanosomes. The present case adds to the 3 mainly or entirely small cell anorectal malignant melanomas described in the literature. There are also at least 12 other cases with less well-defined numbers of small tumor cells or with small cells admixed with other cell morphologies. Documentation of these unusual morphological variants is important for identifying any distinctive outcome they might exhibit compared with conventional malignant melanoma.