Although malignant melanoma is the most common source of metastasis
to the gastrointestinal tract, the features of these metastases as viewed by
magnification endoscopy have not been reported.
A 77-year-old man whose right great toe had been amputated 3 years
previously due to malignant melanoma underwent endoscopy because he was anemic.
Multiple black, depressed lesions (1 – 5 mm in
diameter) with a ”bull’s eye“ appearance were viewed in the
descending duodenum ([Fig. 1]). Under
magnification, the surface of these lesions was smooth ([Fig. 2] and [3]), and
histological examination of a biopsy specimen ([Fig. 4]) revealed tumor cells full of brown pigment
([Fig. 5]). Additional sites of metastasis were
found in the ascending colon (by colonoscopy) and in the pulmonary hilar lymph
node (by CT). Because of appetite loss, the patient underwent gastrointestinal
endoscopy again 2 months later. Increased numbers of black, depressed lesions
were seen, larger than before, and tiny black spots viewed under magnification
showed a similar smooth surface ([Fig. 6]).
Fig. 1 Endoscopy showed a
black, depressed-type tumor in the descending duodenum. It had a
“bull's eye” appearance.
Fig. 2 Magnification endoscopy
revealed the smooth surface of the lesion and the surrounding villi.
Fig. 3 Very smooth surface of
the lesion as shown by magnification endoscopy.
Fig. 4 Photomicrograph of
biopsy specimen showing the very smooth surface of the tumor (arrows) (H&E,
× 40).
Fig. 5 Photomicrograph of
biopsy specimen showing that many malignant melanoma cells had a large amount
of brown pigment (H&E, × 100).
Fig. 6 Magnification endoscopy
revealed that a tiny black spot had a smooth surface.
A diagnosis of malignant melanoma – a frequent source of
metastatic disease in the gastrointestinal tract [1]
[2] – requires identification of melanoma features that
distinguish it from other tumors. The use of magnification endoscopy for this
purpose in the upper gastrointestinal tract is increasingly common. In the
duodenum, Badreldin et al. suggested that zoom endoscopy is valuable in
assessing the degree of villous atrophy in celiac disease [3]. Magnified endoscopic views of early duodenal carcinoma
[4], as well as duodenal metastasis of malignant melanoma
(here), were found to correspond accurately with histopathological findings. We
conclude that magnification endoscopy may be useful, prior to biopsy, for
distinguishing features of gastrointestinal metastases of malignant melanoma,
such as duodenal melanosis and pseudomelanosis.
Endoscopy_UCTN_Code_CCL_1AB_2AZ_3AB
