Aim Blue nevus (BN) is a benign melanocytic proliferation that is typically cutaneous. Extracutaneous BN is infrequent and is reported in the mucosa of various organs. Gastrointestinal (GI) tract BN is rare. Here, we describe the clinicopathological findings of the largest series of GI tract BNs.
Methods A search of our Pathology Data System (1984–2019) identified six GI tract blue nevi. Clinical information, pathology reports and available H&E-stained section slides were reviewed.
Results Lesions predominated in the middle-aged adults (mean 54, range 27–80) with a slight female predominance (66%). Most cases arose in the rectum and colon (83%), with one gastric lesion (17%). Four cases were identified during endoscopic examination performed either for screening or for unrelated symptoms (66%). Two patients presented with rectal bleeding (33%) unassociated with the BN. Endoscopically, most lesions appeared as superficial hyperpigmented areas (83%). One case was described as abnormal mucosa (17%). Microscopically, the mucosa was involved in all of the cases (100%). One case showed submucosal extension in addition to the mucosal component (17%). Lesions showed a proliferation of bland spindle cells with abundant granular pigment. No nuclear atypia or mitoses were identified. Immunostains showed immunoreactivity for melanocytic markers. Follow-up information available for five patients showed no recurrences to date (mean follow-up 1 year).
Conclusions BN is a benign melanocytic proliferation. It is important to be aware of the occurrence of such lesions outside of the skin and consider the possibility of BN when pigmented lesions are encountered in the GI tract.
- pathology, surgical
- gastrointestinal diseases
- gastrointestinal neoplasms
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Handling editor Dhirendra Govender.
Contributors NA gathered the data, reviewed the slides and wrote the manuscript. KS, DH and ALW performed data acquisitions and reviewed the manuscript. LV supervised the process and reviewed the manuscript. EAM, the senior author, supervised the study, provided the cases for the study from her consultation service, reviewed the slides and reviewed the manuscript.
Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.
Competing interests None declared.
Patient consent for publication Not required.
Provenance and peer review Not commissioned; internally peer reviewed.
Data availability statement All data relevant to the study are included in the article. This study is a case series of six cases and all data regarding the study are included in the manuscript.