Polypoid and non-pigmented small-bowel melanoma in capsule endoscopy is common

We read with interest the case report by Urbain et al. “Small-bowel metastasis of malignant melanoma: video capsule endoscopy appearance” [1]. The typical melanotic lesion reported by the authors, “solar eclipse” appearance with the central coal-black lesion encircled by whitish intestinal villi [1], certainly enriches the variety of small-bowel melanoma appearances seen in capsule endoscopy.

In our experience [2], however, and similar to other studies [3] [4], small-bowel metastases in patients with melanoma are predominantly polypoid, and nonpigmented lesions are as common as pigmented ones ([Fig. 1]).

Fig. 1 Nonpigmented small-bowel melanoma.

Hence, the absence of pigmentation does not exclude the diagnosis. Ulceration and/or active bleeding may also be seen ([Fig. 2]).

Fig. 2 Nonpigmented and ulcerated small-bowel melanoma with bleeding.

When the lesion is nonpigmented, and there is no known history of melanoma, diagnosis based on capsule endoscopy appearance can be quite difficult.

We have previously published a case series of capsule endoscopy in 13 patients with suspected small-bowel melanoma. Capsule endoscopy was able to determine the presence and extent of small-bowel metastases more reliably than small-bowel follow-through, computed tomography scan, standard endoscopy, and positron emission tomography scan [2]. Further experience at our center has confirmed these findings. Given that resection of gastrointestinal melanoma metastases is safe, provides effective palliation, and can achieve prolonged remission [5], early diagnosis of small-bowel involvement is therefore of clinical importance and may improve patient outcomes. Capsule endoscopy is the ideal investigation modality for patients with suspected small-bowel metastatic melanoma. This report and our experience underline the variability of the lesions seen at capsule endoscopy in these patients.

Competing interests: W. S. S. is a paid speaker and workshop participant for Given Imaging Pty Ltd.

References

• 1 Urbain D, Aerts M, Reynaert H. et al . Small-bowel metastasis of malignant melanoma: video capsule endoscopy appearance.  Endoscopy. 2010;  42 E185
• 2 Prakoso E, Selby W S. Capsule endoscopy in patients with malignant melanoma.  Am J Gastroenterol. 2007;  102 1204-1208
• 3 Reintgen D S, Thompson W, Garbutt J, Seigler H F. Radiologic, endoscopic, and surgical considerations of melanoma metastatic to the gastrointestinal tract.  Surgery. 1984;  95 635-639
• 4 Bender G N, Maglinte D D, McLarney J H. et al . Malignant melanoma: patterns of metastasis to the small bowel, reliability of imaging studies, and clinical relevance.  Am J Gastroenterol. 2001;  96 2392-2400
• 5 Sanki A, Scolyer R A, Thompson J F. Surgery for melanoma metastases of the gastrointestinal tract: indications and results.  Eur J Surg Oncol. 2009;  35 313-319