Anorectal amelanotic melanoma

Anorectal balloon cell melanoma: a rare variant

Balloon cell melanoma is a rare presentation of malignant melanoma, usually on the skin, with less than 100 cases reported. Mucosal BCM is even rarer, with only one case of anorectal BCM reported in English literature. The diagnosis is based on the histopathologic findings of a tumor composed of large, foamy melanocytes, with or without pigmentation, and confirmed by immunohistochemical studies showing expression for melanocytic markers. The foam cell appearance of the tumor cells and the lack of melanin pigment lead to a diagnostic dilemma, mostly when presented at an unusual location. Herein, we report a case of balloon cell melanoma at the anorectal junction in a 73-year-old male patient complaining of constipation and bleeding per rectum. Surgical resection was performed with no evidence of recurrence after three years of close follow-up. We believe this case will raise awareness among the medical community to consider this tumor a differential diagnosis in rectal masses.

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.

Treatment and outcome trends and predictors of overall survival of rectal melanoma: Analysis of the National Cancer Database

BACKGROUND

We aimed to assess characteristics, treatment, and outcomes of rectal melanoma (RM).

METHODS

This retrospective cohort study looked at patients with RM from National Cancer Database (2004-2019) analyzed characteristics and outcomes of the entire cohort and across three time periods (2004-2009; 2010-2014; 2015-2019). Main outcome measures were change in treatment and survival trends across time periods and overall survival (OS).

RESULTS

641 patients (58.5% female; mean age: 68.2 ± 13.6 years) were included. OS rate was 26%; median survival duration was 17.9 (IQR: 15.93-20.67) months. There was a significant decrease in the use of chemotherapy (17.3%-6.6%; p = 0.001) and surgery (62.9%-41.8%; p = 0.00004) but increased use of immunotherapy (11.9%-52%; p < 0.001) across time periods. OS was longer in the last time period than in the first two (21.8 vs 16.8 vs 16.5 months; p = 0.09). Surgical excision was an independent predictor of improved OS (HR = 0.266, 95%CI: 0.089-0.789, p = 0.017) whereas older age (HR = 1.039, 95%CI: 1.007-1.072, p = 0.016), positive resection margins (HR = 5.06, 95%CI: 1.902-13.48, p = 0.001) and metastasis (HR = 34.62, 95%CI: 3.973-301.6, p = 0.001) were predictors of poor survival.

CONCLUSIONS

Over time, chemotherapy and surgery have been used less often in the treatment of RM while the use of immunotherapy increased by more than four-fold. Older age, surgical treatment, positive resection margins, and metastasis were predictive of survival of RM.

Challenges in managing anorectal melanoma, a rare malignancy

INTRODUCTION AND IMPORTANCE

Anorectal melanoma is a rare and aggressive malignancy that can be difficult to diagnose due to its nonspecific presentation.

CASE PRESENTATION

We present a case of a 69-year-old woman who presented with painful defecation, bleeding per rectum, and a mass coming out of her anal opening. The initial differential diagnosis included hemorrhoids, rectal polyp, or a malignant lesion of the rectum. However, histopathological evaluation following transanal excision of the rectal mass revealed mucosal melanoma in the anorectal region. Further investigation showed no evidence of locoregional or distant metastasis.

CLINICAL DISCUSSION

Surgery remains the primary treatment option for anorectal melanoma, but complete resection is often not feasible, leading to high rates of local recurrence and distant metastasis. The incidence of metastatic disease at the time of presentation is high, and a multidisciplinary approach is necessary to manage these patients. Currently, standard systemic therapies used for cutaneous melanoma are the mainstay of treatment for metastatic anorectal melanoma, but there is a need for further research to develop tailored treatment strategies.

CONCLUSION

Our case report highlights the importance of considering anorectal melanoma in the differential diagnosis of patients presenting with anorectal symptoms. It emphasizes the need for a multidisciplinary approach to managing this rare malignancy. Early diagnosis, a multidisciplinary approach, and ongoing research into more effective treatments are crucial for improving outcomes for patients with anorectal melanoma.

Prolapsed anorectal malignant melanoma presenting as hemorrhoids

Rectal bleeding in a patient with a history of hemorrhoids should not be ignored. It is often benign and resolves spontaneously without treatment. Here we present a case of anorectal malignant melanoma that presented with rectal bleeding and a prolapsed rectal mass.

Effect of surgical treatment for anorectal melanoma: a propensity score-matched analysis of the Surveillance, Epidemiology, and End Results programme data

OBJECTIVE

Anorectal melanoma (AM) is a rare but aggressive tumour with limited information in the existing literature. This study aimed to assess the effect of surgical treatment for AM and predict the prognosis of affected patients.

DESIGN

A retrospective cohort study.

SETTING

Data of patients diagnosed with AM between 1975 and 2016 in the USA were collected from the Surveillance, Epidemiology, and End Results (SEER) database.

PARTICIPANTS

This study enrolled a total of 795 patients with AM from the SEER database and the validation cohort comprised 40 patients with AM enrolled from Chinese institutes.

PRIMARY AND SECONDARY OUTCOME MEASURES

Overall survival (OS) and AM-specific survival (AM-SS).

RESULTS

A total of 795 patients with AM diagnosed between 1975 and 2016 were enrolled in this study. Data over the past four decades showed a trend of increase in incidence rate. A nomogram based on a multivariate Cox regression model was generated to predict AM-SS. The C-index of the nomogram was 0.74 (95% CI 0.71 to 0.77) on internal verification. In the validation cohort, the C-index of the nomogram was 0.72 (95% CI 0.68 to 0.76). The results of propensity score matching (PSM) analysis showed that patients who underwent surgical treatment achieved significant survival (OS: log-rank=17.41, p<0.001; AM-SS: log-rank=14.55, p<0.001). Patients who underwent surgery were stratified into local and extended surgery subgroups. AM-SS and OS were also compared after PSM, but the results were not significantly different between the two surgery subgroups (all p>0.05).

CONCLUSIONS

The nomogram based on the analysis of SEER data showed good performance in predicting OS and AM-SS. Patients with AM can benefit from surgery; however, extensive surgery and appendectomy may not improve AM-SS or OS.

Can transrectal ultrasonography distinguish anorectal malignant melanoma from low rectal adenocarcinoma? A retrospective paired study for ten years

BACKGROUND

Anorectal malignant melanoma (ARMM) and low rectal adenocarcinoma (LRAC) have some similarities in clinical behaviors, histopathological characteristics and ultrasonographic findings, diagnostic errors are common. By comparing the transrectally ultrasonographic features between the two tumors, we propose to provide more possibilities in differentiating them.

METHODS

The data of 9 ARMMs and 27 age- and gender-matched LRACs (the lower margin below the peritoneal reflection) in West China Hospital Sichuan University between April 2008 and July 2019 were retrospectively reviewed. The ultrasonic features between the two groups were compared.

RESULTS

Transrectal ultrasonography (TRUS) showed that the length of ARMM was shorter than that of LRAC (28.22 ± 12.29 mm vs. 40.22 ± 15.16 mm), and ARMM had a lower position than that of LRAC (the distance to anal verge was 50.78 ± 11.70 vs. 63.81 ± 18.73 mm). Unlike LRAC, the majority of ARMM in our study was confined to the intestinal mucosa/submucosa (66.67/25.93%) (P < 0.05).

CONCLUSIONS

Based on the data of our study, several ultrasonographic findings (length, invasion depth, and position) of ARMM were significantly different from LRAC. Accordingly, more attention should be paid to masses at anorectal junction with lower position, shorter length, and shallower infiltration depth. Instead of the most common tumor, LRAC, ARMM should be taken into account to avoid a misdiagnosis, which will result in a poorer prognosis.

Primary melanoma of the anorectal region: clinical and histopathological review of 17 cases. A retrospective cohort study

AIM

The aim of our study was to scrutinize diagnostic and treatment factors that may contribute to the low survival rate from anorectal melanoma while adding 17 more cases to the global research database.

METHOD

We carried out a retrospective analysis of 17 cases of anorectal melanoma treated at a single institution from 2000 to 2020. Data on patient age, sex, complaints, treatment and survival as well as tumour size, resection margins, histological and immunohistochemical features were assessed.

RESULTS

The median age of patients was 72 ± 12.49 (45-92) years. Most of the patients were women (n = 11, 64.71%). Three (17.65%) patients underwent no radical treatment. Of eight patients treated initially with radical surgery (either total mesorectal excision or abdominoperineal resection), six (75%) were found to have positive lymph nodes. Mean survival was 20 ± 23.46 (1-84) months. The average diameter of the resected tumours was 5.43 ± 3.02 cm (1.3-10 cm). Most tumours had epithelioid or spindle cell morphology and were positive for one or more melanocytic markers (S100, HMB-45 or MITF). More than half of the tumours contained no or very little melanin pigment. None of the tumours had significant lymphocytic infiltration. Three tumours showed positivity for keratins (PANCK or CAM5.2) and one tumour showed positivity for C-KIT stain.

CONCLUSION

An aggressive surgical approach may have an effect on survival in most early stages while more advanced disease benefits from a more conservative approach. Attention to sentinel lymph nodes and further systemic research into therapy is required. For now, treatment and diagnostic modalities seem to be inconsistent, requiring further investigation to elucidate common points.

Safety and efficacy of electrochemotherapy in a series of patients with nonmetastasized primary or recurrent anorectal malignant melanoma

Anorectal malignant melanoma (AMM) is a rare malignant tumor. Surgery remains the gold standard but new adjuvant treatments to allow local sphincter-saving are warranted. Electrochemotherapy (ECT) is an alternative to surgery in selected cohorts of patients. To evaluate safety and efficacy of ECT in a retrospective series of patients with primary or recurrent AMM in terms of local disease control, local progression free and overall survival. Seven primary and one recurrent AMM underwent ECT. Patients were followed at 1 and 2 months and at the longest available follow-up with clinical examination and/or ultrasound. One month after ECT 6/8 (75%) patients showed complete response, 1/8 partial response (12.5%) and 1/8 stable disease (12.5%), confirmed at 2 months. Bleeding stopped in all patients, and pain was absent or mild/moderate in all patients. No serious adverse events were observed. At 1 year of follow-up seven out of eight patients were alive (87.5%), four were disease-free and three were alive with disease. At the longest available follow-up (mean 4.9 ± 2.0 years) five out of eight (62.5%) of patients were still alive. Our study showed that ECT is well tolerated and effective in the treatment of patients with anal melanoma with good local control of disease.

Genetic alteration of Chinese patients with rectal mucosal melanoma

Background

Rectal mucosal melanoma (RMM) is a rare and highly aggressive disease with a poor prognosis. Due to the rarity of RMM, there are few studies focusing on its genetic mechanism. This retrospective study aimed to analyze the genetic spectrum and prognosis of RMM in China and lay a foundation for targeted therapy.

Methods

36 patients with primary RMM from Peking University Cancer Hospital were enrolled in this study. The Next-generation sequencing (NGS) data of the tumor samples were fitted into the TruSight™ Oncology 500 (TSO500) Docker pipeline to detect genomic variants. Then, the univariate and multivariate Cox hazard analysis were performed to evaluate the correlations of the variants with the overall survival (OS), along with Kaplan-Meier and log-rank test to determine their significance.

Results

BRAF mutations, NRG1 deletions and mitotic index were significant prognostic factors in the univariate analysis. In multivariable analysis of the OS-related prognostic factors in primary RMM patients, it revealed 2 significant alterations: BRAF mutations [HR 7.732 (95%CI: 1.735–34.456), P = 0.007] and NRG1 deletions [HR 14.976 (95%CI: 2.305–97.300), P = 0.005].

Conclusions

This is the first study to show genetic alterations exclusively to Chinese patients with RMM. We confirmed genetic alterations of RMM differ from cutaneous melanoma (CM). Our study indicates that BRAF and NRG1 were correlated with a poor prognostic of RMM and may be potential therapeutic targets for RMM treatment.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-021-08383-6.

Distribution pattern of tumor infiltrating lymphocytes and tumor microenvironment composition as prognostic indicators in anorectal malignant melanoma

Anorectal malignant melanoma (ARMM) is a rare disease with poor prognosis. Determining ARMM prognosis precisely is difficult due to the lack of proper assessment techniques. Immunotherapy has proven effective against cutaneous malignant melanoma and may show efficacy in ARMM. Herein, we assessed the immune profile of ARMM to identify possible prognostic biomarkers. Twenty-two ARMM formalin-fixed and paraffin-embedded samples were evaluated using an nCounter^® PanCancer Immune Profiling Panel. Validation was performed through immunohistochemical staining for CD3, CD8, Foxp3, CD68, CD163, and PD-L1. RNA analysis revealed significantly decreased scores for pathways involved in cell regulation and function, as well as chemokines, in recurrent patients compared to nonrecurrent patients. In cell-type profiling, the recurrent cases displayed significantly low tumor infiltrating lymphocyte (TIL) scores. Recurrence/death prediction models were defined using logistic regression and showed significantly lower scores in recurrent and deceased patients (all, P < 0.001) compared to those in nonrecurrent and surviving patients. The high total TIL and tumor-associated macrophage (TAM) groups had significantly better overall survival outcomes compared to the low total TIL and TAM groups (P = 0.007 and P = 0.035, respectively). In addition, the presence of CD3 + TILs in the invasion front was an independent favorable prognostic indicator (P = 0.003, hazard ratio = 0.21, 95% confidential interval, 0.01-0.41). Patients with inflamed or brisk-infiltration type tumors also had a significantly better overall survival than that of patients with immune-desert/excluded and absent/non-brisk type tumors (P = 0.03 and P = 0.0023, respectively). In conclusion, TILs have a strong prognostic value in ARMM, and the quantification of TILs and an analysis of the TIL phenotype and infiltration pattern during pathological diagnosis are essential to guide treatment strategies and accurate prognosis in ARMM.

A case report of anorectal malignant melanoma in the transitional zone

INTRODUCTION

Anorectal malignant melanoma is an uncommon and highly malignant disease with a greater incidence in females. Many patients were misdiagnosed as hemorrhoids, benign polyps, and rectal cancer. They were often diagnosed in an advanced stage. Wide local excision and abdominoperineal resection are the main treatments of rectal melanoma.

PRESENTATION OF CASE

A case report is a 77-year-old man who has blood in the stool for 4 months without clinical examination. He admitted to the emergency room with sudden syndromes that related to bowel perforation. Rectal examination detected a large anorectal polyp. Computer tomography showed free air and fluid in the peritoneal cavity. He was received laparoscopic surgery and found the fishbone penetrated the sigmoid colon without polyp resection. The polyp was treated by local excision a few days later. The histology examination was a primary malignant melanoma. Due to the pigmented lesion that remained from the resected polyp's root, the abdominoperineal resection was performed as a radical treatment.

DISCUSSION

Diagnosis of anorectal malignant melanoma is difficult because of atypical signs, that are confused with bleeding hemorrhoids especially an amelanotic melanoma. Treatment is controversial, including surgery, radiotherapy, chemotherapy, and target therapy. A present case is an option in radical surgery.

CONCLUSION

Anorectal melanoma is a rare disease with poor results and prognosis. A lack of large-data leads to a missing evidence-based guideline in this disease. Early-staging diagnosis and surgical treatment help patients improve their overall survival.

Long-term response to ipilimumab after nivolumab failure in a case of anorectal melanoma with an intermediate tumor mutation burden and negative for PD-L1 expression

Anorectal melanoma is a rare disease with a poor prognosis and its response to immunotherapy remains poorly studied. The current study reports a case of recurrent anorectal melanoma in a 60-year-old woman that has exhibited a durable response to ipilimumab for >2 years. Given that the combination of nivolumab and ipilimumab was not approved for use in unresectable or metastatic melanoma at the time of presentation, the patient was initially treated with nivolumab monotherapy and switched to ipilimumab after nivolumab failure. The tumor was microsatellite stable, had an intermediate tumor mutation burden and was negative for programmed cell death-ligand-1 expression. However, the neutrophil-to-lymphocyte ratio in peripheral blood remained at <5 throughout the disease course. Although mucosal melanoma is not caused by ultraviolet radiation and has a lower mutation burden than cutaneous melanoma, the present case responded well to immunotherapy. Further evaluation of potential biomarkers for such patients is required.

Endoscopic diagnosis of gastrointestinal melanoma

Background: Gastrointestinal (GI) melanoma can be diagnosed by endoscopy combined with biopsy and subsequent pathological examination. However, the disease may be misdiagnosed due to the limited awareness of GI melanoma.Objective: We aimed to describe characteristics of GI melanoma that can be detected by endoscopy and endoscopic ultrasound (EUS).Methods: We retrospectively analyzed patients with GI melanoma diagnosed by endoscopic biopsy or postoperative pathology between August 2008 and January 2017. Images of endoscopic examinations, including endoscopy and EUS, were reviewed to characterize GI melanomas.Results: A total of 21 patients (9 males, 12 females) with GI melanoma were enrolled in this study. Several types of melanoma were identified: anorectal melanoma (n = 15), esophageal melanoma (n = 3), gastric melanoma (n = 2), and melanoma of the small intestine (n = 1). EUS was performed for one case of esophageal melanoma, one case of gastric melanoma, and seven cases of anorectal melanoma.Conclusions: GI melanoma is a rare disease. Most GI melanomas showed typical endoscopic manifestations, including black plaques. EUS is a reliable tool for evaluating the depth of infiltration of GI melanoma.

Spindle cell proliferations of the sigmoid colon, rectum and anus: a review with emphasis on perineurioma

A wide range of spindle cell proliferations are found uncommonly in the sigmoid colon, rectum and anus. They usually present as polyps, and include reactive lesions and benign and malignant neoplasms which may be primary or metastatic. They are less frequently described in the literature compared to those in the upper gastrointestinal tract, and may be underdiagnosed. The widespread use of sigmoidoscopy in symptomatic patients and bowel cancer screening programmes means that histopathologists must be aware of, and adopt a logical approach to, diagnosing spindle cell proliferations in biopsy and polypectomy specimens. This is particularly relevant given the strong association of some mesenchymal polyps with hereditary cancer syndromes. This review article will focus on perineurioma and the recent debate in relation to its overlap with fibroblastic polyp. The clinical, endoscopic, histological and immunohistochemical features of spindle cell proliferations which should be considered in the differential diagnosis of perineurioma will be discussed. There is also a brief reference to malignant spindle cell tumours of diagnostic importance.

Treatment Strategies and Survival Trends for Anorectal Melanoma: Is it Time for a Change?

BACKGROUND

Immunotherapy advances for the treatment of cutaneous melanoma question its efficacy in treating anorectal mucosal melanoma (ARMM). We aimed to identify the prevalence, current management, and overall survival (OS) for ARMM.

METHODS

Review of patients with ARMM from 2004 to 2015 National Cancer Database. Factors associated with immunotherapy were identified using multivariable logistic regression. The primary outcome was 2- and 5-year OS. Subgroup analysis by treatment type was performed.

RESULTS

A total of 1331 patients were identified with a significant increase in prevalence (2004: 6.99%, 2015: 10.53%). ARMM patients were older, white, on Medicare, and from the South. The most common treatment was surgery (48.77%), followed by surgery + radiation (11.75%), surgery + immunotherapy (8.68%), and surgery + chemotherapy (8.68%). 16.93% of patients received immunotherapy, with utilization increasing (7.24%: 2004, 21.27%: 2015, p < 0.001). Patients who received immunotherapy had a significantly better 2-year OS (42.47% vs. 49.21%, p < 0.001), and other therapies did not reveal a significant difference. Adjusted analysis showed no difference in 2- and 5-year OS based on therapy type.

CONCLUSION

The prevalence of ARMM has increased. The use of immunotherapy has increased substantially. Some survival benefit with the administration of immunotherapy may exist that has yet to be revealed. A more aggressive treatment paradigm is warranted.

Primary malignant melanoma without melanosis of the colon

Primary malignant melanoma (PMM) of the gastrointestinal tract is rare. Reported cases of PMM of the lower gastrointestinal tract typically describe anal and rectal involvement rather than colonic lesions. This report describes a rare case of a 50-year-old woman with PMM originating in the colon. The patient presented to Inje University Busan Paik Hospital with a 3-day history of blood-tinged stools. She underwent colonoscopy for a diagnosis of hematochezia. The colonoscopic examination revealed a large-sized semi-pedunculated sigmoid colon polyp with a reddish-colored mucosal surface. Endoscopic mucosal resection was performed, and the final histopathological findings were consistent with a diagnosis of malignant melanoma. Systemic work-up was performed for assessment of metastasis and to identify the primary tumor considering the high metastatic rate of gastrointestinal malignant melanoma; however, no other malignant lesion was detected. Thus, she was diagnosed with colonic PMM. She underwent laparoscopic low anterior resection and lymph node dissection and has been recurrence-free for > 2 years.

Primary Dedifferentiated Amelanotic Anorectal Melanoma: Report of a Rare Case

Anorectal melanoma (ARM) is an uncommon aggressive malignancy that comprises 0.5% to 1.6% of all melanoma manifestations. Dedifferentiated melanoma is very rare with loss of all melanocytic differentiation markers and is usually seen in metastatic melanoma of cutaneous origin. In this article, we report the first case of primary dedifferentiated amelanotic ARM in a 68-year-old male who presented with anal discomfort that was initially treated as inflamed hemorrhoids. Physical examination revealed a large protruding anal mass, biopsy of which showed biphasic malignant tumor cells with distinct immunoprofiles: a superficial spindled/sarcomatoid component positive for SOX10 and S100, and a deeper epithelioid/rhabdoid component positive for desmin, AE1/AE3, and EMA. Both components were negative for HMB-45, Melan-A/MART-1, c-Kit, and other lineage markers. Molecular analysis by polymerase chain reaction demonstrated wild-type BRAF and KRAS genes. A diagnosis of dedifferentiated ARM was made based on the coexistence of a differentiated component (spindled: S100 and SOX10 positive) and a dedifferentiated component (epithelioid: all melanoma markers including S100 and SOX10 negative). Shortly afterwards, the patient developed extensive pulmonary and liver metastases and expired 20 days after the diagnosis was rendered, reinforcing the highly aggressive nature of this disease entity.

Multiple synchronous anorectal melanomas with different colors: A case report

BACKGROUND

Anorectal melanoma (AM) is an extremely rare malignant tumor originating from anorectal melanocytes with a poor prognosis. AM has been reported to have a much lower incidence than cutaneous or choroid melanoma, accounting for 0.4%-1.6% of all melanomas.

CASE SUMMARY

We report a 76-year-old female patient diagnosed with anorectal malignant melanoma by colonoscopy and biopsy. Intraoperative examination revealed two distinct anorectal tumors, one melanotic and another amelanotic, as well as two pigmented mucosal zones at the dentate line level. Abdominal perineal resection was performed. A pathological report confirmed all four lesions to be melanomas. Postoperatively, we followed an immunotherapy protocol targeting PD-1 (nivolumab). The patient had 24 mo of disease-free follow-up upon completion of nivolumab treatment.

CONCLUSION

This is the first reported case presenting coexistence of pigmented and unpigmented AMs in the same patient.

Primary Anorectal Amelanotic Melanoma: The First Case Report from Saudi Arabia

Anorectal melanomas are exceptionally uncommon and only 30% of anorectal melanomas are amelanotic. We report here a case of an anorectal amelanotic melanoma in a female patient. An 84-year-old patient complained of anal mass for 3 months. On examination, there was a 7.0 cm mass prolapsing through the anus that was pale-pink in color. Abdominal, pelvic, and chest computed tomography (CT) showed rectal wall thickening with an eccentric polypoid soft tissue density mass, and left inguinal and presacral lymph node enlargement along with a small nodule in the lower lobe of the left lung, likely representing metastatic deposit. Microscopic examination revealed a piece of skin with hyperplastic squamous epithelium with surface ulceration. The dermis and underlining tissue were showing infiltration by malignant sheets and nests of ovoid and spindle shape cells with prominent nucleolus and high mitotic s. Immuno-staining for HMB-45, S-100, and Melan-A was positive, and it was negative for P63, CK 5/6, and Pan-CK, thus confirming it as an anorectal amelanotic melanoma, and not an epithelial tumor. This is the first case of an amelanotic anorectal melanoma reported from Saudi Arabia.

Anorectal mucosal melanoma

Anorectal melanoma is an uncommon and aggressive mucosal melanocytic malignancy. Due to its rarity, the pre-operative diagnosis remains difficult. The first symptoms are non-specific such as anal bleeding, anal mass or pain. Although anorectal melanoma carries a poor prognosis; optimal therapeutics strategies are unclear. Surgical resection remains the mainstay of treatment. The optimal surgical procedure for primary tumours is controversial and can vary from wide local excision or endoscopic mucosal resection (EMR) to an abdomino-perineal resection. A high degree of uncertainly exists regarding the benefit of radiation therapy or chemotherapy. The treatment of advanced melanoma is evolving rapidly with better understanding of the disease biology and immunology. Considerable effort has been devoted to the identification of molecular determinants of response to target therapies and immunotherapy.

Primary anorectal mucosal melanoma detected by anorectal cytology

The detection of primary anorectal melanoma on anal cytology is a rare and challenging diagnosis. We report a case where anorectal cytology showed isolated malignant cells with oval nuclei, prominent nucleoli, and elongated wispy cytoplasmic projections. There was no evidence of squamous dysplasia or melanin pigment identified. To the best of our knowledge, this is the first reported case of a primary anorectal melanoma detected in anorectal cytology. Detection of malignancies other than squamous cell carcinoma can be seen on anorectal cytology and should be considered when there is no evidence of anal intraepithelial neoplasia. Diagn. Cytopathol. 2017;45:452-455. © 2017 Wiley Periodicals, Inc.

Primary rectal melanoma - a case report

The most common site for malignant melanoma is skin, then eye and third is anorectal region. Primary anorectal malignant melanoma is still very uncommon. It is usually very aggressive and presents with altered bowel habit and rectal bleeding. Proctoscopy shows non-pigmented or lightly pigmented polypoid lesion. Histopathology is confirmatory. Early radical excision is mandatory. A 56 year-old female was presented with malignant melanoma of the lower third of rectum. We report this case for its rarity.

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.

Anorectal melanoma: diagnosis and treatment

An increase in the incidence of anorectal melanoma has recently been noted in the United States. Anorectal melanoma is an uncommon and lethal condition, with a median survival of <20 months. Unfortunately, nonspecific symptoms also attributable to common and benign conditions (eg, hemorrhoids) cause significant delay in its diagnosis. Although it has not been validated by clinical trials, abdominoperineal resection has historically been the treatment of choice for this disease. However, for the past 2 decades, a lack of clear survival benefit has led to a shift toward less-mutilating wide local excisions. Controversy still exists regarding the benefit of radiation therapy and chemotherapy. Furthermore, the value of nodal surgery in anorectal melanoma is unclear. In this article, we review the history and current status of management of anorectal melanoma, with a particular focus on surgical controversies and challenges in optimizing survival.

Anorectal malignant melanomas: Retrospective experience with surgical management

AIM: To present the experience and outcomes of the surgical treatment for the patients with anorectal melanoma from the Cancer Hospital, Chinese Academy of Medical Sciences.

METHODS: Medical records of the diagnosis, surgery, and follow-up of 56 patients with anorectal melanoma who underwent surgery between 1975 and 2008 were retrospectively reviewed. The factors predictive for the survival rate of these patients were identified using multivariate analysis.

RESULTS: The 5-year survival rate of the 56 patients with anorectal melanoma was 20%, 36 patients underwent abdominoperineal resection (APR) and 20 patients underwent wide local excision (WLE). The rates of local recurrence of the APR and WLE groups were 16.13% (5/36) and 68.75% (13/20), (P = 0.001), and the median survival time was 22 mo and 21 mo, respectively (P = 0.481). Univariate survival analysis demonstrated that the number of tumor and the depth of invasion had significant effects on the survival (P < 0.05). Multivariate analysis showed that the number of tumor [P = 0.017, 95% confidence interval (CI) = 1.273-11.075] and the depth of invasion (P = 0.015, 95% CI = 1.249-7.591) were independent prognostic factors influencing the survival rate.

CONCLUSION: Complete or R0 resection is the first choice of treatment for anorectal melanoma, prognosis is poor regardless of surgical approach, and early diagnosis is the key to improved survival rate for patients with anorectal melanoma.

Malignant melanoma of the anorectum--a rare entity

OBJECTIVE

Primary anorectal melanoma is a rare entity with a poor prognosis accounting for approximately 0.1-4.6% of anal tumours and 0.5-1.6% of all melanomas. Almost 60% of patients have already disseminated disease at initial diagnosis.

METHOD

We report four cases of anorectal melanoma treated at our department from November 2006 to September 2008, as well as a review of the literature.

RESULTS

There were two females and two males, of median age 69 years (range: 59-81 years). Most frequent complaints were rectal bleeding and/or anorectal pain. Three of our four patients had amelanotic melanomas. We found the positive expression of S-100 protein and HMB-45 in two patients and melanin A cells in one case. Abdominoperineal resection was performed in two patients, colostomy in one patient and a wide local excision also in one case. Three patients died on account of dissemination of melanoma, one patient is still alive.

CONCLUSION

Anal melanoma remains a deadly problem. Clear guidelines for the therapy of anorectal melanoma have not been established. This mainly results from the rarity of this tumour. Treatment is based on retrospective studies, which report a limited number of cases.

Diffuse anorectal melanoma; review of the current diagnostic and treatment aspects based on a case report

Primary anorectal melanoma is a rare and aggressive disease. Patients commonly complain for changes in bowel habits and rectal bleeding, and proctoscopically they mostly appear as non pigmented or lightly pigmented polypoid lesions. Such a lesion should always raise a high index of suspicion in any gastroenterologist or surgeon to prompt surgery, since early radical excision is the only treatment option.

Herein, we report a case of a 57-year-old man with a diffuse anal canal melanoma and give reference to the current diagnostic and treatment options.