Primary small-bowel melanoma: color Doppler ultrasonographic, computed tomographic, and radiologic findings with pathologic correlations

Malignant Melanoma of the Gastrointestinal Tract: Symptoms, Diagnosis, and Current Treatment Options

Malignant melanoma (MM) has become the fifth most frequent cancer in the UK. It is the most common carcinoma to metastasize to the gastrointestinal (GI) tract. MM particularly has an affinity to spread to the small bowel, which is followed by the involvement of the stomach and large intestine. Excellent endoscopic options including video capsule endoscopy and enteroscopy are available for a precise diagnosis of GI involvement by a metastatic MM. The complete surgical resection of GI metastatic MM in carefully selected patients not only provides symptom control, but has also been associated with an increase in overall survival. The approval of BRAF-targeted therapies and immune checkpoint inhibitors has transformed therapeutic approaches for patients with metastatic MM over the past decade. Currently, the overall survival of patients with advanced metastatic MM who have been treated with a combination of immunotherapeutic agents reaches 52% at five years. The role of surgery for patients with the metastatic involvement of the GI tract with MM is evolving in the era of effective systemic treatments.

Melanoma Metastasizing to the Small Intestine: A Case Report Illustrating Symptomatic and Asymptomatic Involvement

Symptomatic gastrointestinal (GI) involvement of melanoma is rare, however, it is a frequent autopsy finding in patients with primary cutaneous melanoma. We present a case of metastatic cutaneous melanoma with initial asymptomatic jejunal involvement as found on a positron emission tomography (PET) scan, with subsequent duodenal perforation.

A 69-year-old man presented to the hospital with a three-week history of worsening headache, dizziness, and vomiting with a history of Clark level III malignant melanoma that was completely excised from the right flank three years ago at the hospital. A magnetic resonance image of his brain revealed a subacute right-sided cerebellar hemorrhage adjacent to a 1-cm nodule. He underwent a right suboccipital craniomy with resection; the biopsy of which revealed metastatic malignant melanoma. A staging positron emission tomography (PET) scan revealed areas of increased uptake of fludeoxyglucose (FDG) in the left lower lung and left upper quadrant of the abdomen abutting the small bowel. Subsequent enteroscopy revealed a 40-mm cratered jejunal ulcer with heaped edges; the biopsy of which also revealed malignant melanoma. Since he had widespread disease, abdominal surgery was deferred, and treatment with ipilimumab and radiotherapy to the brain was initiated. He presented three months later with acute abdominal pain and diarrhea. A computed tomography scan of his abdomen revealed free peritoneal air, and an exploratory laparotomy revealed a mass at the antimesenteric border of the duodenum with a biopsy consistent with melanoma. The perforated area was resected and an end-to-end anastomosis was performed. Unfortunately, our patient had a postoperative intracranial hemorrhage and was referred to palliative care.

Our case portrays how malignant melanoma may metastasize insidiously and widely and present as a catastrophe. Melanoma involvement in the GI tract is a poor prognostic marker. Our case offers a unique illustration of both the occult and manifest gastrointestinal involvement of melanoma and underscores the importance of clinical suspicion in patients with a history of melanoma who present with unexplained GI symptoms.

Metastatic malignant melanoma of the small bowel--report of two cases

CASE REPORT

We report two cases of malignant melanoma metastasizing to the ileum and jejunum in a 48-year-old female and 62-year-old male, respectively. The female patient was a known case of vaginal melanoma who on follow-up developed pain abdomen 4 years after excision of the primary, whereas the male patient who was initially referred as pleomorphic spindle cell sarcoma of the groin presented with complaints of bleeding per rectum and melena 6 years later.

RESULTS

After preliminary investigations both underwent laparotomy and resection of segments of ileum and jejunum with tumor. Histopathological examination with immunohistochemistry showed features suggestive of metastatic malignant melanoma.

DISCUSSION

Metastasis should be suspected in patients with malignant melanoma who develop gastrointestinal symptoms such as abdominal pain, anemia, melena, fatigue, constipation, small bowel obstruction, or perforation. This helps in avoiding a delay in the diagnosis and complications that arise due to metastatic disease.

CONCLUSION

Our first patient with primary vaginal melanoma died of multiple metastases 11 months following surgery for the ileal metastasis while the second patient with jejunal metastasis developed recurrent disease in the small bowel and iliac lymph nodes 10 months after surgery. However, in a patient with isolated gastrointestinal metastasis, diagnosed early, with good general condition surgical management should be encouraged when a complete resection of the disease is feasible as no other treatment option is as good for relief of symptoms and prolongation of life.

Tumor cells disseminate early, but immunosurveillance limits metastatic outgrowth, in a mouse model of melanoma

Although metastasis is the leading cause of cancer-related death, it is not clear why some patients with localized cancer develop metastatic disease after complete resection of their primary tumor. Such relapses have been attributed to tumor cells that disseminate early and remain dormant for prolonged periods of time; however, little is known about the control of these disseminated tumor cells. Here, we have used a spontaneous mouse model of melanoma to investigate tumor cell dissemination and immune control of metastatic outgrowth. Tumor cells were found to disseminate throughout the body early in development of the primary tumor, even before it became clinically detectable. The disseminated tumor cells remained dormant for varying periods of time depending on the tissue, resulting in staggered metastatic outgrowth. Dormancy in the lung was associated with reduced proliferation of the disseminated tumor cells relative to the primary tumor. This was mediated, at least in part, by cytostatic CD8+ T cells, since depletion of these cells resulted in faster outgrowth of visceral metastases. Our findings predict that immune responses favoring dormancy of disseminated tumor cells, which we propose to be the seed of subsequent macroscopic metastases, are essential for prolonging the survival of early stage cancer patients and suggest that therapeutic strategies designed to reinforce such immune responses may produce marked benefits in these patients.

Melanoma of the small intestine

Intestinal melanomas can be primary tumours or metastases of cutaneous, ocular, or anal melanomas. Primary intestinal melanoma is extremely rare, whereas metastatic melanoma of the small bowel is common because of the tendency for cutaneous melanoma to metastasise to the gastrointestinal tract. Because distinguishing between primary and metastatic intestinal melanoma can be difficult, the main features of each are discussed, and the diagnostic images used to detect intestinal melanoma are assessed. Routine barium examinations and CT have limited sensitivity, but PET imaging can improve detection of melanoma metastases to the small bowel. Although various treatment strategies have been tried in patients with intestinal melanoma, surgical removal of intestinal metastases is the treatment of choice in patients with resectable tumours. No systemic therapy improves survival in patients with melanoma metastatic to the intestines; thus, the prognosis for these patients is poor. Patients with primary melanoma of the small intestine have a worse prognosis than do patients with metastases of cutaneous melanoma.