Melanoma ano-rectal amelanótico primario. reporte de un caso / Primary amelanotic ano-rectal melanoma. a case report

RESUMEN: Se presenta el caso de una mujer de 37 años, que acude a la consulta por sensación de bulto anal y hematoquecia de 3 meses de evolución, con antecedente de estreñimiento. No presenta prurito, dolor anal ni pérdida de peso. A la inspección, presenta lesión tumoral de 3 cm, en cuadrante superior izquierdo de la región anal, de aspecto denudado, color rosado y mucosa anal hiperpigmentada. La histopatología reporta un tumor de células redondas, sugestivo de melanoma. La inmunohistoquímica confirma finalmente el diagnóstico, pues reporta positividad a los marcadores S100, HMB45 y Vimentina. Al realizar el estudio a los cuatro meses de evolución de extensión de la enfermedad, se encuentran implantes de la neoplasia a nivel pulmonar e inguinal, lo que demuestra la agresividad y el pobre pronóstico de esta patología.

SUMMARY: We present the case of a 37-year-old woman, who came to the clinic for a sensation of anal bulge and hematochezia of 3 months of evolution, with a history of chronic constipation. No pruritus, anal pain or weight loss. On inspection, she presented a 3 cm tumor in the upper left quadrant of the anal region, pink and denuded in appearance. The adjoining mucosa was hyperpigmented. Histopathology reports a round cell tumor, suggestive of melanoma. Immunohistochemistry finally confirms the diagnosis, since it reports positivity to S100, HMB45 and vimentin markers. When performing the disease extension study, implants of the neoplasm are found at the pulmonary and inguinal level, which demonstrates the aggressiveness and poor prognosis of this pathology.

Primary Anorectal Malignant Melanoma Treated With Endoscopic Mucosal Resection

Anorectal melanoma is a rare neoplasm that accounts for less than 1-4% of anorectal malignant tumors. The main therapeutic modality for anorectal melanoma is surgical treatment, with abdominoperineal resection or wide local excision being the most common approaches. A 77-year-old male with a history of cerebral infarction and hypertension presented with anal bleeding. Here, we report a case of anorectal melanoma treated by endoscopic mucosal resection with adjuvant interferon therapy rather than surgical resection. The patient has been disease-free for 5 years after endoscopic treatment.

Anorectal melanoma: histopathological and immunohistochemical features and treatment / Melanoma anorretal: diagnósticos histopatológico e imunohistoquímico e tratamento

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. (AU)

Os melanomas anorretais (ARM) devem ser caracterizados pela localização (anal, retal e anorretal), coloração, dimensão, forma e mobilidade. Microscopicamente, por tipos de melanócitos, graduação da pigmentação melânica, alterações juncionais sob o epitélio escamoso, índice mitótico atípico, atipias celulares e citoplasmáticas, infiltrado inflamatório, invasões vascular e perineural, linfonodo sentinela e penetração parietal. Devem ser estadiados pelos critérios American Joint Committee on Cancer (AJCC) e/ou TNM Classification of Malignant Tumours (TNM). Como as células do ARM são variáveis, isto torna difícil o diagnóstico diferencial com outros tumores da região anorretal. Assim, faz-se necessária a realização de IHC. Apresentamos uma série de 14 pacientes, nos quais foram refeitos exames histológicos e realizados IHCs com vários marcadores, firmando corretamente o diagnóstico. Os trabalhos mostram que a cirurgia mais racional é a excisão local alargada (ELA) em casos de doença localizada e ressecção abdominoperineal do reto (APR) para lesões avançadas. Independente da técnica, a sobrevida de cinco anos é inferior a 35%; a sobrevida média não ultrapassa 26 meses; o tempo livre de doença é inferior a 10 meses; e a sobrevida global não ultrapassa é de 32 meses. Não há correlação entre melhora dos resultados com qualquer tratamento adjuvante. As terapias-alvo para doença metastática começam a apresentar resultados animadores, ainda inconclusivos. (AU)

Treatment Outcomes of Anorectal Melanoma

PURPOSE: An anorectal melanoma (AM) is a very rare tumor. However, sufficient data supporting effective surgical options for the disease do not exist. This retrospective review aimed to analyze treatment outcomes for an AM. METHODS: From June 1999 to December 2008, we retrospectively reviewed a prospectively collected consecutive series of 19 patients who had undergone a surgical resection for an AM at a single institute. Surgical method and clinicopathological factors were analyzed. RESULTS: The median age was 61.4 years (range, 46 to79 years). Main symptoms were an anal mass, hematochezia, perianal pain, tenesmus, fecal incontinence, and bowel habit change. The average duration of symptoms before diagnosis was 7.8 months (range, 1 to 36 months). S-100 and HMB-45 were positive in all patients, even in non-melanin pigmentation. There were 12 abdominoperineal resections (APRs) and 7 wide local excisions (WEs). The APR showed longer overall survival when compared with the WE (64.1 months vs. 10.9 months, P < 0.001). No patients who underwent a WE survived more than 13 months. CONCLUSION: A high index of suspicion is necessary to establish the diagnosis for an AM in patients with anal symptoms, and S-100 and HMB-45 can be useful markers for an AM. Even with the small number of cases and the short follow-up, our data suggest that an APR for an AM may provide longer survival than a WE.

Melanoma de canal anal simulando doença hemorroidária: relato de caso / Melanoma of the anal canal simulating hemorrhoidal disease: case report

O Melanoma Anorretal é um tumor maligno raro com a possibilidade de simular uma doença anorretal, tornando o diagnóstico difícil. Tem baixos índices de cura e elevados índices de mortalidade em curto prazo. Os autores descrevem um caso de melanoma de canal anal cuja interpretação por parte do paciente tratava-se de uma doença hemorroidária que exteriorizava às evacuações. Os autores fazem uma extensa revisão da literatura dando ênfase aos sintomas e a melhor opção terapêutica a ser instituída.

Anorectal melanoma is a rare malignant tumor with the small chance of simulating anorectal disease, making the diagnosis hard. There is a low rate of cure and high rate of short term mortality. The authors describe a case of anal melanoma which by the patients interpretation was hemorrhoid disease that exteriorized evacuations. The authors do an extensive evaluation of the literature, giving emphasis to the symptoms and the best therapeutic option to be used.