Primary Anorectal Melanoma Research Articles

Surgical Management of Primary Anorectal Melanoma: Is Less More?

PurposeAno-uro-genital (AUG) Mucosal Melanoma UK guidelines recommended a less radical surgical strategy for anorectal melanoma (ARM) where possible. We report our experience of ARM consistent with that approach including clinical presentation, intervention undertaken and prognosis.MethodsWe present a retrospective study of 15 consecutive patients with ARM surgically treated between November 2014 and April 2023. Patients were divided into the two surgery types: wide local excision (WLE, n = 9) and abdominoperineal resection (APR, n = 6). Data on demographics, diagnosis, treatment and oncological outcomes were assessed between the groups.ResultsThe mean age was 65.3 ± 17.4 years and 6 (40.0%) were female patients. Nine patients (60.0%) were diagnosed with stage I and six patients (40.0%) with stage II disease. R0 margins were achieved in all cases. The overall mean length of stay was lower following WLE compared to APR (2.6 ± 2.4 days versus 14.0 ± 9.8 days, p = 0.032). Two complications were observed in the WLE group compared to four complications after APR (p = 0.605). Five patients (55.5%) developed local/distant recurrence in the WLE group compared to three patients (50.0%) in the APR group (p = 0.707), with a median overall survival of 38.5 (12–83) months versus 26.5 (14–48) months, respectively.ConclusionsAchieving clear margins by the least radical fashion may have equivalent oncological outcomes to radical surgery, potentially reducing patient morbidity and preserving function. In our experience, the surgical management of ARM consistent with the ‘less is more’ approach adhering to AUG guidelines has acceptable outcomes.

Optimal surgical management strategy for treatment of primary anorectal malignant melanoma-a systematic review and meta-analysis.

Primary mucosal anorectal malignant melanoma (AMM) is an invasive malignancy with poor survival. Management options have been variable, due to limited data and lack of randomised control trials available on the optimal surgical strategy. The aim of this review was to compare local excision versus radical resection. A systematic searchof articles in PubMed, Ovid, Scopus, and the Cochrane Library database was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines.The outcomes of interest were the impact that surgical strategy had on survival (primary) and recurrence rates (secondary) for the treatment of AMM, comparing sphincter sparing local excision (LE) versus extensive abdominoperineal resection (APR). Ten studies met the predefined criteria. Overall, there were 303 patients, with a median age of 58.2years. Sixty-one percent (n = 187/303) had radical surgery (abdominoperineal resection) for the primary treatment of AMM. Overall, 5-year survival for the APR and LE was 23% and 32% respectively. Meta-analysis on the median OS noted no statistical difference between the two groups. However, local recurrence occurred in 20.82% and 47.04% in the APR and LE groups respectively. Meta-analysis observed a statistically significant reduction in recurrence when patients had an APR as primary treatment (OR 0.15, 95% CI = 0.08-0.28, p < 0.00001). Though local recurrence rates are more common with local excision of AMM, this does not confer an inferior OS when comparing LE versus APR. The decision to proceed with LE vs. APR should be made on a case-by-case basis.

Treatment outcomes and prognostic factors in 47 patients with primary anorectal malignant melanoma in the immune therapy era.

Primary anorectal melanoma (ARM) accounts for approximately 1.2% of all melanomas and 16.5% of all mucosal melanomas. ARM is associated with the shortest interval to disease progression and the highest rate of metastasis; however, optimal therapeutic strategies for ARM remain controversial. This study aimed to assess the ideal surgical intervention for ARM and to determine the effect of immune checkpoint inhibitors (ICI). We included 47 patients with ARM treated at the National Cancer Center Hospital in Japan from 2011 to 2020. We performed a survival analysis for each of these groups: (i) patients with ARM (n = 47); (ii) operable non-stage IV cases at initial presentation (n = 35); and (iii) stage IV cases (n = 32). The 5-year overall survival (OS) was 53.6%, and the median OS was 78.7months in patients with ARM. No statistically significant difference in 5-year OS was found between rectal and anal sites (50.9% vs. 56.7%). In the non-stage IV subgroup, the type of surgery (abdominoperineal resection or wide local excision) did not correlate with OS (HR 1.85; 95% CI 0.46-7.5; p = 0.39). In the stage IV subgroup, the 2-year OS of the ICI treatment group was 61.4%, whereas that of the dacarbazine regimen group was 0% (p = 0.048). Our ARM prognosis was better than that of previous studies. Our findings suggest that the availability of ICI therapy may improve survival in patients with advanced ARM. However, further research is warranted to identify both the clinical and molecular predictors of response to improve patient selection.

Primary Anorectal Malignant Melanoma: Case Report and Review of Literature

Anorectal malignant melanomas are rare and aggressive tumors. The diagnosis is based on pathological exams. We reported the case of a 54 years old patient who underwent a surgical resection for rectal melanomas diagnosed after histological exams of rectal biopsy tissues.

BRAF, NRAS, KIT, TERT, GNAQ/GNA11 Mutation Profile and Histomorphological Analysis of Anorectal Melanomas: A Clinicopathologic Study.

Primary anorectal melanomas (AMs) are uncommon neoplasms with aggressive behavior. Molecular profile and clinicopathologic features of AMs are still not well established. In this study, we aimed to investigate BRAF, NRAS, KIT, TERT, and GNAQ/GNA11 mutation status and clinicopathologic features of AMs. All diagnostic slides of 15 AMs were reviewed. Histopathological and follow-up information were documented. Mutations in exon 15 of the BRAF gene; exons 2 and 3 of the NRAS gene; exons 9, 11, 13, 17, and 18 of the KIT gene; and exons 4 and 5 of the GNAQ/GNA11 genes and mutations in the promoter region of the TERT gene (chr.5, 1,295,228C > T and 1,295,250C > T) were analyzed. BRAF(V600E) and KIT(V555I and K642E) mutations were observed in one (7%) and two cases (14%), respectively. NRAS, TERT and GNAQ/GNA11 mutations were not detected. The mean age was 65. Patients presented with rectal mass, rectal bleeding, pain, and weight loss. 73% of the lesions were macroscopically polypoid. The most common tumor cell type was epithelioid. Mean tumor thickness was 10.4 mm. One third of the cases lacked pigmentation. In situ melanoma was present in one third of the cases. Among 14 patients with follow-up data, 12 succumbed to disease. The mean overall survival was 36 months. AMs are uncommon tumors with dismal survival, usually occurring in the elderly in various gross and microscopic appearances. In terms of molecular profile, BRAF and KIT mutations are rarely detected. Profiling of larger cohorts is required to elucidate the pathogenesis and to identify potential molecular indicators that may contribute to the development of individualized targeted therapies.

A rare case of polypoid primary anorectal melanoma with subsequent giant stomach metastasis: A gastrointestinal involvement of both primary and metastatic mucosal melanoma.

Melanoma can involve the gastrointestinal apparatus as both primary and metastatic lesions. Primary anorectal mucosal melanoma (ARMM) and metastatic gastric melanoma are rare entities and usually resulted in a poor prognosis. We presented a case of a 61-year-old man who after the complete excision of an ARMM developed a gastric metastasis after almost three years form the complete tumour excision. Upon esophagogastroduodenoscopy, a giant ulcered mass resulted in melanoma metastasis. The patient underwent a near-total gastrectomy. After five months of follow-up, the patient is disease-free. The incidence of ARMMs is increasing, highlighting the necessity of new prevention and treatment strategies in order to achieve a better prognosis for these patients. There are no known risk factor for ARMMs but surgery, together with the combination of anti-CTLA-4 and anti-PD-1 antibodies, are promising therapeutic options. Early and aggressive treatments are required, together with a strict multidisciplinary approach.

Primary anorectal malignant melanomas: retrospective analysis of 11 cases in a single center.

Anorectal malignant melanoma is a rare tumor with poor prognosis. In this study, it was aimed to present our surgical results by reviewing the literature retrospectively in 11 patients who underwent surgery for ARMM in our clinic. The patients who underwent surgery for anorectal malignant melanoma in Yuksek İhtisas Training and Research Hospital between 2007-2018 were included in the study. Four patients were males and seven were females. Mean age was 54.18. The tumor was in the rectum in 4 cases, in the anorectal region in 3 cases and in the anal canal in 4 cases. Wide local excision was performed in 3 cases and APR was performed in 8 cases. Four of the cases were stage I, 6 were stage II and 1 was stage III. Mean tumor size was 4.73 cm, and mean tumor depth was 13.6 mm. Mean number of metastatic lymph nodes was 10.37. Median survival was 12 months. Anorectal malignant melanoma is a type of tumor diagnosed in late and advanced stages due to lack of specific findings. Although ARMM is rare, when rectal bleeding, pain, hemorrhoids and changes in bowel habits are observed, ARMM should be kept in mind.

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.

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.

S1774 Primary Anorectal Malignant Melanoma: Rare and Fatal

INTRODUCTION: We present an uncommon diagnosis of primary anorectal malignant melanoma (ARMM) in a patient with anemia and altered bowel habits. Primary ARMM accounts for less than 4% of anorectal malignancies and less than 1.5% of all melanomas. ARMM can often go undiagnosed, which is detrimental to patients due to its aggressive nature. CASE DESCRIPTION/METHODS: 63 y.o. African American male with a history of ascending colon resection for colon adenocarcinoma 8 years prior was referred for change in bowel habits and nausea with eating. He had worsening intermittent constipation, but denied melena or blood in his stool. He had nausea 45 minutes after eating but no vomiting. He denied recent weight loss. His last colonoscopy was a year after colon resection. The ileocolonic anastomosis was at 70 cm from anal verge, there was a 3 mm hyperplastic polyp in the sigmoid and repeat colonoscopy was recommended in a year. Physical exam was negative for skin hyperpigmentation, moles or lesions. Abdominal exam was negative for tenderness, guarding or rebound. Labs showed normocytic anemia, Hgb 8.1 g/dl from 12 g/dl the year prior. Digital rectal exam revealed a firm immobile mass, 3 cm from anal verge. Colonoscopy showed a fungating, ulcerated, non-obstructing 3 cm mass in the rectum. Biopsies were done with cold forceps for histology. Pathology noted the mass had brownish pigmentation and extensive necrosis, consistent with malignant melanoma. Immunohistochemical staining was positive for S-100, HMB-45, Melan-A and SOX-10 supporting the diagnosis. A diagnosis of primary anorectal malignant melanoma was made as patient had no evidence of cutaneous or ocular melanoma. PET scan showed metastasis to a large pelvic lymph node so patient was not a surgical candidate. Oncology started patient on immunotherapy with ipilmumab and nivolumab. DISCUSSION: Primary ARMM is a rare malignancy, especially in African Americans such as our patient, with a poor prognosis. As with our case, presenting symptoms can be unspecific such as anemia. Often patients with ARMM present with rectal bleeding that is attributed to hemorrhoids and endoscopic intervention is not pursued. This is detrimental as it causes a delay in diagnosis. Our patient’s mass was pigmented, but in 29% of cases the mass may be amelanotic resulting in misdiagnosis. Treatment is abdominoperineal resection if there is no evidence of metastasis. Our case highlights the importance of recognizing primary ARMM as a cause of rectal bleeding in patients with an anorectal mass.Figure 1.: Retroflexed view in the rectum revealing the pigmented, ulcerated, non-obstructing 3 cm mass at 3 cm from anal verge.Figure 2.: The mass is composed of melanoma cells that formed irregular nests and cords, and manifested enlarged and hyperchromatic nuclei with irregular nuclear contours and prominent nucleoli. The pigments were finely granular and brownish. (H&E, x200).Figure 3.: Immunohistochemistry demonstrated the tumor cells to be positive for S-100 (Fig. A, cytoplasmic stain, fast red; X100), HMB-45 (Fig. B, cytoplasmic stain, fast red; X100) and SOX-10 (Fig. D, nuclear stain, fast red; X100). They were negative for expression of pan-cytokeratin, the brown granules in the background are melanin pigments (Fig.C, AE1/3, lack of cytoplasmic stain, DAB; X100).

S1742 Not as It Appears: A Case of Amelanotic Anorectal Melanoma

INTRODUCTION: Primary anorectal melanoma (ARM) is a rare entity with anorectal presentation accounting for 0.4- 1.6% of all primary melanomas. ARM has an incidence of 0.5-4% of all anorectal malignancies. It presents after the fifth decade of life with nonspecific complaints. In patients taken for colonoscopy, diagnosis and resection can be difficult as lesions may be amelanotic and spread along submucosal planes. With incidence increasing, it is especially important to recognize ARM as a source of morbidity and mortality. CASE DESCRIPTION/METHODS: Our patient is an 89 yo female with Non-Hodgkin lymphoma presenting with left lower quadrant abdominal pain. Her pain was associated with loose stools and hematochezia attributed to hemorrhoids. The patient endorsed colonoscopy 10 years ago and had no polyps identified on any prior studies. Her labs demonstrated WBC of 71, Hgb of 12 with CT A&P demonstrating thickening and fat stranding at the rectum and splenic flexure. Physical exam was notable for tenderness on palpation of the LLQ, and rectal exam demonstrated a palpable mass proximal to the anal verge. The patient was taken for flexible sigmoidoscopy. Sigmoidoscopy demonstrated a non-bleeding malignant appearing 5 cm mass within the rectum which was non-circumferential, just above the dentate line, with multiple cold forceps biopsies taken. Pathology returned as suspicious for malignant melanoma with sections demonstrating an epithelioid malignancy with scattered pigmented cells. This sample was sent for further evaluation, and demonstrated a subepithelial proliferation of poorly differentiated malignant cells in a sheet like configuration. The nuclei displayed severe pleomorphism and the cytoplasm was granular and eosinophilic with questionable, focal pigmentation. By immunohistochemistry, tumor cells showed Mart-1 and CD31 coexpression with focal S-100 staining. The results were thought to represent a poorly-differentiated malignant melanoma. These findings were discussed with the patient, and it was determined she had a poor prognosis with no option for aggressive treatment. Patient did elect for hospice. DISCUSSION: ARM carries a poor prognosis. This is due to misdiagnosis as hemorrhoids, polyps and other rectal cancer. At the time of diagnosis only 37% of ARM is confined at the anorectal area. Surgical resection is the mainstay of treatment for those with local disease. As ARM spread along submucosal planes and are often beyond complete resection, early recognition of ARM is of the utmost importance.Figure 1.: Rectal mass.Figure 2.: Rectal mass.

Primitive Anorectal Malignant Melanoma: A Rare And Aggressive Localization A Case Report

Primary anorectal malignant melanoma is an extremely rare condition. It appears at the third highest frequency after melanomas of the skin and retina. Its prognosis is dreadful because of the early onset of metastases. The treatment remains essentially surgical. We report an observation of primitive anorectal melanoma, collected at the department of surgery for digestive cancers and liver transplantation of the Ibn Rochd University Hospital of Casablanca, with a review of the literature. In order to analyse the clinical, paraclinical and therapeutic characteristics of primary anorectal melanoma.

P-42 Primary malignant melanoma of anorectal region: An institutional experience in AIIMS Patna

Primary anorectal melanoma (ARM) is a rare neoplasm, accounting for 0.25%– 1.25% of malignancies originating in the anorectal region with poor prognosis despite aggressive management. Owing to its rare incidence and aggressive course, data regarding ideal management is lacking. Surgery is still the preferred modality of treatment.

Primary Malignant Melanoma of Anorectum CT Findings: a Single Tertiary Center's Experience.

Anorectal melanoma is a rare malignancy with very aggressive course. This case series emphasize the role of imaging, contrast-enhanced computed tomography in evaluating such cases before surgery. CT scan of four patients with pathologically proven primary anorectal malignant melanoma was included. CT findings were analyzed from the picture archiving and communication system for the site of involvement, morphological shape, presence of perirectal and anal infiltration, lymphadenopathy, liver metastasis, and occurrence of bowel obstruction for all the four patients. All the four patients presented as polypoidal mass that caused focal expansion and obscuration of rectal lumen without causing colonic obstruction. Perirectal infiltration was seen in 2/4 patients and involvement of anal canal was seen in 3 patients. Distant metastasis was seen in the liver in three out of four patients. In conclusion, primary anorectal malignant melanoma is a rare, highly aggressive tumor and should be considered in patients with a bulky intraluminal polypoid mass that does not cause colonic obstruction in the anorectal region with large-sized lymphadenopathy.

Primitive Anorectal Malignant Melanoma: A Rare But Aggressive Tumor

We report 2 observations of primary anorectal melanoma, collected over a period of 2 years from December 2017 to December 2019, as well as data from the literature. The patients nevertheless benefited after the histological evidence with an additional immunohistochemical study of an extension assessment made by pelvic MRI and thoracoabdominopelvic CT scan. The patients were classified stage I according to the Slingluff classification. They underwent abdominoperineal resection with definitive left iliac colostomy and adjuvant Chemotherapy.

A rare case of recurrent primary anorectal melanoma emphasizing the importance of postoperative follow-ups

BackgroundPrimary anorectal melanoma can be a rare differential diagnosis of anorectal mass. Due to the low case number reported in the literature, physicians are not aware of this aggressive disease. Although no consensus exists, wide local excision and abdominoperineal resection are considered the mainstay therapy.Case presentationAn 85-year-old female patient presented with fecal incontinence 5 years after local resection of a primary anorectal melanoma. In the rectoscopy, a tumor proximal to the dentate line was identified and later confirmed as a recurrent primary anorectal melanoma. There were no signs of locoregional or distant metastasis on the MRI and PET/CT. She underwent another wide local excision and regained fecal continence postoperatively.ConclusionsPrimary anorectal melanoma should belong to the differential diagnosis of anorectal mass. If technically feasible, wide local excision represents a less invasive treatment than abdominoperineal resection, retaining the anal sphincter and patient’s quality of life. Even though wide local excision has a higher recurrence rate than abdominoperineal resection, there is no difference in survival between the two procedures. This is only under the premise that patients are followed-up regularly after wide local excision so that recurrence can be spotted early on and locally excised.

Management and outcomes of primary anorectal melanoma in the United States.

Aims: To analyze outcomes in primary anorectal melanoma, a rare disease with limited data and treatment guidelines. Materials & methods: We analyzed 305 subjects in the National Cancer Database from 2004 to 2015. The primary end point was overall survival (OS). Results: Surgery was predictive of OS (median 2.24 vs 1.18 years; p = 0.009) with no survival difference between local and transabdominal approaches (p = 0.77). No OS benefit was seen with chemotherapy (p = 0.16), radiotherapy (p = 0.31) or adjuvant therapy post surgery (p > 0.05 for all groups). Targeted therapy trended toward higher survival in metastatic patients (1.33 vs 0.55 years; p = 0.06). Conclusion: In nonmetastatic patients, surgery of any method is associated with a survival benefit. The trend for improved survival following targeted therapy in metastatic patients merits further exploration.

Primary anorectal melanoma: Multimodality management in a series of four cases and review of literature

Primary anorectal melanoma: Multimodality management in a series of four cases and review of literature

1568 Don't Skip the Retroflexion: A Case of Disseminated Anorectal Mucosal Melanoma

INTRODUCTION: Less than 4% of melanomas are of mucosal origin with primary anorectal mucosal melanomas comprising a small subset. Mucosal melanomas are often diagnosed late due to delay in patient presentation and obscured tumor origins noting a more aggressive behavior and less favorable prognosis when compared to cutaneous melanomas. We present a case of metastatic anorectal mucosal melanoma with a negative colonoscopy 1-year prior. CASE DESCRIPTION/METHODS: A 68 year-old female presented to the hospital with a history of several months of intermittent fecal impaction complicated by sporadic outlet type rectal bleeding and a negative colonoscopy 1-year prior. She endorsed progressive anorexia and a 20 lb. weight loss over the last few months. She was hemodynamically stable with normal hemoglobin level. CT imaging depicted multiple lesions in the liver and lungs concerning for metastatic disease. A colonoscopy was repeated and revealed a rigid mass on rectal exam and granular nodularity with ulceration in the rectum at the dentate line on retroflexion (Figure 1). Excisional biopsy confirmed mucosal melanoma. Same session endoscopic ultrasound showed several lesions in the left lobe of the liver with FNA demonstrating malignant melanoma (Figures 2 and 3). MRI revealed primary tumor involvement of the anal canal and rectum in addition to metastases to the liver, lungs, and lymph nodes. The patient was diagnosed with T4N1M1, stage IV anorectal mucosal melanoma (BRAF/C-KIT negative) and was recommended to undergo ipilimumab and nivolumab (I3/N1) immunotherapy with palliative radiation. DISCUSSION: Anorectal mucosal melanomas occur infrequently, but at the time of diagnosis, are more likely to be metastatic with poor prognoses. Rectal bleeding is the most common symptom, and diagnosis is often seen in fifth to seventh decade of life. This case is a prime example of not only the aggressive nature of anorectal mucosal melanoma presenting with disseminated disease despite normal colonoscopy 1-year prior but also of the significance of the rectal exam and retroflexion maneuver during colonoscopy.

Prognostic model for patient survival in primary anorectal mucosal melanoma: stage at presentation determines relevance of histopathologic features.

Pathological staging of primary anorectal mucosal melanoma is often performed according to the American Joint Commission on Cancer (AJCC) guidelines for cutaneous melanoma, as an anorectal melanoma-specific staging system does not exist. However, it remains unknown whether prognostic factors derived for cutaneous melanoma also stratify risk in anorectal melanoma. We retrospectively determined correlations between clinicopathological parameters and disease-specific survival in 160 patients. Patients were grouped by clinical stage at presentation (localized disease, regional or distant metastases). Cox proportional hazards regression models determined associations with disease-specific survival. We also summarized the somatic mutations identified in a subset of tumors analyzed for hotspot mutations in cancer-associated gene panels. Most of the patients were white (82%) and female (61%). The median age was 62 years. With a median follow-up of 1.63 years, median disease-specific survival was 1.75 years, and 121 patients (76%) died of anorectal melanoma. Patients presenting with regional (34%) or distant metastases (24%) had significantly shorter disease-specific survival compared to those with disease localized to the anorectum (42%). Of the 71 anorectal melanoma tumors analyzed for hotspot genetic alterations, somatic mutations involving the KIT gene (24%) were most common followed by NRAS (19%). Increasing primary tumor thickness, lymphovascular invasion, and absence of regression also correlated with shorter disease-specific survival. Primary tumor parameters correlated with shorter disease-specific survival in patients presenting with localized disease (tumor thickness) or regional metastases (tumor thickness, absence of regression, and lymphovascular invasion), but not in patients presenting with distant metastases. Grouping of patients according to a schema based on modifications of the 8th edition AJCC cutaneous melanoma staging system stratified survival in anorectal melanoma. Our findings support stage-specific associations between primary tumor parameters and disease-specific survival in anorectal melanoma. Moreover, the AJCC cutaneous melanoma staging system and minor modifications of it predicted survival among anorectal melanoma patients.