Acute mechanical intestinal obstruction secondary to malignant melanoma metastasis

Abstract

A 33-year-old male patient was referred to our emergency and trauma unit with abdominal pain that started 3 days ago. On physical examination, widespread abdominal tenderness and rebound were noticed. His medical history consisted of right scrotal malignant melanoma excision 5 years ago. The patient received adjuvant interferon treatment for 7 months and discontinued follow-up. Laboratory tests revealed a leukocyte count of 12  100/mm³, CRP level of 73 mg/L, and blood gas lactate value of 3.2 mmol/L. Air-fluid levels were observed on the standing direct abdominal radiograph. Radiological studies revealed jejuno-jejunal intussusception (Figure 1A,B). What is your diagnosis? Furthermore, what will be the right management strategy?

Diagnostic laparotomy was performed and tumor implants invading small intestine serosa, widespread pigmented lesions on the omentum, and mesentery were observed. (Figure 1C,D). Tumoral lesions blocked the small intestinal lumen at 30th, 90th, and 190th cm from the ligament of Treitz. The mass which was located at 30th cm from Treitz caused intussusception. No other pathology was detected. A total of 60 cm resection, including the invaginated area and aforementioned masses, were performed. Side-to-side and functional end-to-end anastomoses were performed with a stapler. The patient was discharged on post-operative day 6 without any further complications. Macroscopic examination revealed multiple tumor masses with different sizes in the wall of small intestine. Microscopic examination revealed tumor cells, many of which contain dark brown pigment with spindle or ovoid/round morphology containing multiple mitotic figures. The findings were consistent with malignant melanoma metastasis in the present patient with a known history of malignant melanoma. (Figure 2) Follow-up period of 2 years revealed no recurrences of gastrointestinal symptoms and intestinal metastasis. The patient was lost to follow-up after second year of surgery.

Symptomatic small intestine metastasis of malignant melanoma is extremely rare. In autopsy series, intestinal metastasis of malignant melanoma has been shown to be 50% to 58% and symptomatic cases are estimated to be 2% to 5% of all intestinal metastatic cases.^{1, 2} Most of these cases present with abdominal pain, obstructive symptoms, and gastrointestinal bleeding due to the obstructive effect of the polypoid lesions or intussusception of metastatic segments.³

Small intestine metastasis should be kept in mind in patients with acute abdomen with a history of malignant melanoma. Acute abdomen may be secondary to intussusception, bleeding, and obstruction. Early surgical intervention is necessary to ensure intestinal continuity and prevention of complications such as perforation. Furthermore, appropriate oncological treatment should be planned as soon as possible to prevent further systemic metastasis.

Fatih Yanar: data curation, formal analysis, and writing—original draft. Oğuzhan Şal: data curation, formal analysis, and writing—original draft. Berke Şengün: conceptualization, methodology, writing—original draft. Nail Ömer: conceptualization, formal analysis, and methodology. İbrahim Fethi Azamat: methodology, funding acquisition, and writing—review and editing.

There is no financial relationship relevant to this article to disclosure.

The authors declare no conflicts of interest.

The study was conducted following the Declaration of Helsinki criteria as well as Declaration of Istanbul criteria. Due to the study being performed as retrospective study with anonymized data analyses, ethical committee approval was not required.