ABSTRACT
Malignant melanoma of the anorectum is a very uncommon malignancy. It is associated with relatively poor prognosis and surgery is the only treatment. In this report, we present the treatment options for huge anorectal malignant melanoma. An 83-year-old female patient presented with anorectal pain and hemorrhage. A tumor extending from the verge of the anus to 6 cm into the rectum was observed on colonoscopy. Biopsy revealed malignant melanoma. Abdominoperineal resection was performed. Surgery is the most widely accepted treatment approach. Abdominoperineal resection should be the first-line treatment who have large tumors.
Introduction
Primary anorectal malignant melanoma is a highly uncommon malignancy that is thought to originate from melanocytes in the mucosa around the anorectal region. Anorectal malignant melanoma is associated with a comparatively low prognosis and surgical treatment is the only curative treatment. This case demonstrates the treatment option for huge anorectal malignant melanoma.
Case Report
A 83-years-old female applied with anorectal pain and hemorrhage. Her history had hemorrhoidectomy procedure that performed by another clinic one month ago and pathological examination revealed malignant melanoma. The patient was transferred to our clinic for further evaluation and surgical treatment. She had no history of any viral infection and smoking. A anorectal tumor was discovered during a digital rectal examination. On the colonoscopy of the patient, a tumor was seen that extending from the anal verge to the 6 cm of rectum. A biopsy of anorectal tumor displayed malignant melanoma. Gastroscopic examination had normal findings. Computerized tomography of the abdomen and pelvis demonstrated a huge, lobulated mass arising in the anus and extending upwards along the rectum with a lobulated contour. No abdominal lymphadenopathy and distant metastasis was found. Pelvic magnetic resonance imaging demonstrated a wide, solid appearing mass that involves a significant portion of the anal sphincter. The mass extended upwards from the perirectal region of the anus, coursing around the rectum with an additional lobulation. A few perirectal and pelvic lymph nodes were seen, with no additional adenopathy and no free fluid in the abdomen. The abdominoperineal resection was performed (Figure 1). The final tumor stage was IIc (0/15 nodes). The patient didn’t want getting adjuvant treatment due to her advanced age. The patient’s one year follow-up normal.
Discussion
Primary anorectal malignant melanoma is an uncommon malignancy and presents nearly 1% of all malignant melanomas, nearly 23.8% of mucosal melanomas, and between 0.5 and 2% of all colorectal malignancies.1 These lesions are discovered more frequently with in 6 cm of the anal verge and can affect either the anal canal, the rectum, or both.2 It arises in the rectum in 42% and anal canal in 33%. Risk factors are not obviously described apart from the contribution with human immunodeficiency virus infection.3 Patients typically apply with anorectal hemorrhage or a mass, anorectal pain or change in bowel wont. Sometimes, melanoma is an random pathologic finding after hemorroidectomy procedure and/or anal polypectomy.4 Our patient applied with anorectal pain and hemorrhage. These findings are sustained with the standard feature of primary anorectal malignant melanoma. Primary anorectal malignant melanoma is incorrect diagnosis in about 80% of the patients as a non-pigmented polypoid lesions, rectal wound, other anorectal tumors, or hemorrhoids.2 Due to our patient had hemorrhage story, hemorrhoidectomy procedure had been performed her. Paratumoral area lymph node combination is seen in 60% of patients and distant metastases are present at diagnoses in about 30%.5 Various publications display that 20-62% of the cases, at the time of the diagnosis, had distant metastases. The most common areas of metastasis are the liver, lung, bone and brain.6 At the time of diagnosis, our patient was found to have no other organ involvement. Sometimes, patients with anorectal melanoma apply with isolated local disease that is most probably resectable for healing. Recurrence relation is extensive and generally happens consistently to the detriment of the primary surgical operation. Local resection with nontumor borders does not raise the risk of recurrence, and abdominoperineal resection presents no survival benefit over local procedure. Because of the morbidity related with abdominoperineal resection, wide local surgery procedure is suggested for primary treatment of localized anal melanoma. Sometimes, wide local excision might not be possible and abdominoperineal resection might be necessaried if the tumor wraps a considerable component of the anal sphincter. The addition of adjuvant treatment (chemotherapy, vaccine, radiotherapy) might be of profit in a few patients, but usefulness maintains uncorroborated.7 We had perform abdominoperineal resection because of our patient’s tumor had involved the portion of anal sphincter. The patient didn’t adjuvant treatment due to her advanced age. Primary anorectal malignant melanoma is an uncommon condition. Patients typically apply with anorectal hemorrhage or a mass, anorectal pain or change in bowel wont. The course of disease is highly worse. Given the rareness of this disease, treatment is moot. Surgical option is the most widely accepted approach to treatment. Abdominoperineal resection should be the first option treatment like our patient’s who have large tumors.
