Artifacts of benign pigmented nevi presumed to be shrinkage during tissue-processing are described. These produce separation into clefts or nests leaving spaces that simulate lymphatic or vascular spaces. The artifact was found in 10% of 350 otherwise unremarkable benign pigmented nevi. Actual lymphatic invasion probably also occurs in benign nevi but was observed in only one instance. A second artifact results in nevus cells separating into parallel rows. The latter artifact was reproduced in ten experimental subjects by intralesional injections of local anesthetic, and involved from 10% to 90% of the cross-sectional area of the nevus. Knowledge of these artifacts can prevent misdiagnosis or subclassification of these histologie artifacts.
Sagebiel RW. Histologie Artifacts of Benign Pigmented Nevi. Arch Dermatol. 1972;106(5):691-693. doi:10.1001/archderm.1972.01620140039011