Occult invasion of in situ melanoma is possible, but it is rare, according to study results recently published in JAMA Dermatology.
Researchers used the melanoma database on patients with in situ melanoma at the University of Michigan Comprehensive Cancer Center between Jan. 1, 2012, and July 31, 2014, to identify unequivocal in situ melanoma without associated nevi or regression. There were 33 in situ melanomas in a consecutive cohort plus one nonconsecutive index case identified. A patient who developed a regional lymph node metastasis 7 years after the initial diagnosis in 2007 was used as the index case.
