Mesenteric Schwannoma, Intestinal Malrotation and Ileal Diverticulum: A Unique Association.

Mesenteric schwannomas are rare benign tumors that arise in the mesentery. Ileal diverticula and intestinal malrotation in adults are rare findings, since they are usually asymptomatic. We present the case of an 86-year-old man, without any known previously known medical conditions, who was admitted in the emergency department with recurrent abdominal distension and intense pain. The radiological study suggested an intestinal malrotation. An exploratory laparotomy confirmed the intestinal malrotation with intermesenteric bands, as well as a mesenteric mass adjacent to an ileal diverticulum. Following a segmental enterectomy, the histology of the mass reported a mesenteric schwannoma. To the best of our knowledge, this is the first report of such association. We therefore present this report to showcase the diagnostic and therapeutical challenges in managing these conditions.

Os schwanomas mesentéricos são tumores benignos raros com origem nas células de Schwann do mesentério. Divertículos ileais e má-rotação intestinal em adultos são também achados raros, por serem geralmente assintomáticos. Neste artigo apresentamos o caso de um homem de 86 anos, sem antecedentes conhecidos, que recorre à urgência por um quadro de dor abdominal e distensão. O estudo imagiológico sugeria uma má rotação intestinal, pelo que se realizou uma laparotomia exploradora, onde se verificaram várias bandas intermesentéricas, bem como uma massa mesentérica adjacente a um divertículo ileal. Foi realizada lise de bandas e uma enterectomia segmentar. A avaliação anatomo-patológica mostrou tratar-se de um schwanoma mesentérico. Tanto quanto é do nosso conhecimento, este é o primeiro relato de um caso com esta associação tripla, e tem como objetivo reforçar os desafios diagnósticos e terapêuticos na abordagem destas patologias.

Epithelioid melanoma of the rectum: reappraisal of a deceptive microscopic simulator.

We report 2 cases of rectal melanoma. The patients were a 48-year-old man and an 88-year-old woman. In both cases, the tumor presented as polypoid and necrotic masses, making initial diagnostic assessment difficult because of the regressive tissue changes. Microscopically, tumors were mostly composed of epithelioid, highly atypical cells mimicking poorly differentiated carcinoma or large cell lymphoma. Tumor cells were negative for keratin, leukocyte common antigen, and epithelial membrane antigen and positive for S100 protein and several melanoma markers, although in endoscopic biopsy specimens, the positive reaction was focal due to the limited viable tissue. One patient was treated with abdominoperineal resection. Pathologic examination of the surgical specimen revealed a polypoid mass infiltrating the muscle coat of the rectum. Local lymph nodes contained metastatic deposits. Microscopic examination of the rectal mucosa adjacent to the infiltrating neoplasm revealed colonization of the intestinal crypts by atypical melanocytes. This patient is alive 1 year after surgery with no evidence of recurrent disease. The other case was not deemed amenable to radical surgery because of the patient's advanced age and evidence of diffuse metastatic disease. She was alive 6 months after the initial diagnosis but was lost to follow-up. Data indicate that the diagnosis of melanoma, although feasible in large resection specimens, may be problematic in endoscopic biopsy, especially when only small tissue fragments are available and tumor regression hampers the accuracy of immunohistochemical stains. Documentation of intracryptic atypical melanocytes in nonneoplastic mucosa conceptually corroborates claims that rectal melanoma is related to preinvasive precursors as in cutaneous melanoma.