Takamichi Ito1,2, Yuichi Yoshida1, Nanako Yamada1, Masutaka Furue2 and Osamu Yamamoto1
1Division of Dermatology, Department of Medicine of Sensory and Motor Organs, Faculty of Medicine, Tottori University, Tottori, and 2Department of Dermatology, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashiku, Fukuoka 812-8582, Japan. E-mail: email@example.com
Accepted Mar 19, 2013; Epub ahead of print Jun 5, 2013
Colorectal cancer occurs in more than 1.2 million people worldwide every year (1). In principle, the most effective treatment for colorectal cancer is total resection of the tumour with adequate margins. A stoma is formed after surgical resection if necessary. Since various skin diseases can occur around the stoma, appropriate stoma care and management of these lesions, including early detection of peristomal metastasis, are important. We report here a case of peristomal lesions (benign mucosal polyps and subsequently occurring peristomal metastasis) and their dermoscopic findings.
A 77-year-old Japanese man presented with a 1-month history of a slow-growing mass around a colostomy stoma in the left side of the abdomen. Four years previously, he had undergone Hartmann’s operation for sigmoid colon adenocarcinoma (T3 N1 M0, Stage IIIb). Since then, he had developed repeated hyperplastic polyps on the stoma and peristomal skin (Fig. 1) and had been treated with polypectomy or cryotherapy each time. There had been no evidence of malignancy on histopathological examination of those polyps.
Fig. 1. (a) Clinical features of hyperplastic polyps on the colostomy site 3 years before consultation. (b) Dermoscopy of hyperplastic polyps showing regularly arranged dotted and glomerular vessels on a homogenous milky-pink-to-white background.
Physical examination of the new, slow-growing mass revealed a pedunculated, dark-red nodule located on the peristomal skin. The nodule bled easily and was 2 cm in size and covered with a necrotic crust (Fig. 2a). Dermoscopically, polymorphous vascular structures (dotted, irregular linear and looped vessels) and antler-like irregular white-to-pink structures were randomly arranged (Fig. 2b). The tumour was suspected to be a malignancy, and biopsy was performed. Histopathological examination revealed atypical tumour cells with oval and hyperchromatic nuclei and columnar cytoplasm proliferating in a glandular fashion. Many mitotic figures were also observed.
Fig. 2. (a) A dark-red nodule on the peristomal region. (b) Dermoscopy of peristomal metastasis showing randomly arranged polymorphous vessels and irregular white-to-pink structures.
Based on these findings, a diagnosis of peristomal skin metastasis of colon cancer was made. Serum carcinoembryonic antigen (CEA) level was elevated to 3,451 ng/ml (<5.0 ng/ml), and computed tomography revealed multiple liver metastases. The patient did not wish to undergo further radical treatment and is currently receiving supportive care.
A stoma can be created into any hollow organ of the body, including the oesophagus, stomach, duodenum, ileum, pleural cavity, ureters and urinary bladder. As in the case of a colostomy site, various skin disorders can arise around these stomas and clinicians are sometimes consulted about them. Providing a correct diagnosis of these lesions, however, is sometimes difficult.
Dermoscopy is now widely used to diagnose pigmented or non-pigmented skin diseases. Previous studies have demonstrated that specific vascular patterns are important for discerning benign or malignant non-pigmented tumours, such as amelanotic melanoma and squamous cell carcinoma (2, 3). Zalaudek et al. (2) reported that a polymorphous vascular pattern should always raise the index of suspicion for malignant skin tumours. Since there have been only a few reports dealing with dermoscopic features of skin metastasis from internal tumours (4–6), typical features of skin metastasis are still unclear. In the present case, clinical features of the metastatic tumour strongly suggested a malignant process, and dermoscopy showed a polymorphous vessel pattern, which is also compatible with malignancy. Interestingly, in dermoscopic images of benign hyperplastic polyps of this patient, glomerular vessels and dotted vessels were arranged in a regular manner. This vascular pattern in polyps is completely different from that seen in metastasis, and suggests a benign nature.
Differential diagnoses of our case included intestinal metaplasia. Adachi et al. (7) reported the dermoscopic features of peristomal intestinal metaplasia. In the literature, dermoscopy showed hairpin and dotted vessels with a milky-white background, similar to the features of polyps in our case. We speculate that these are unique features of benign mucosal lesions.
Diagnostic accuracy for peristomal lesions might be improved by dermoscopy in some cases, although the current dermoscopic images of peristomal metastasis may fail to add much additional information over the clinical images.
The authors declare no conflicts of interest.