Regression structures / Blue white structures
In this chapter we describe blue white structures network and its histopathological correlation
It has the following subchapters:
|White scar-like depigmentation||Ralph P. Braun, Oriol Yélamos|
|Granularity / Peppering||Ralph P. Braun, Oriol Yélamos|
|Blue whitish veil||Ralph P. Braun, Katrin Kerl, Oriol Yélamos|
On histopathology fully evolved regression shows fibrosis and melanosis (infiltrate of melanophages), and sparse lymphocytic infiltrates. The normal undulating DEJ pattern formed by rete ridges and dermal papillae is attenuated to completely Flattened. Regression structures consisting of both scar like depigmentation and peppering (granularity) should raise suspicion for melanoma. Regression structures consisting of only peppering can be seen in melanoma, lichen planus like keratosis and nevi. In lichen planus like keratosis the granularity tends to be coarse and diffusely distributed. In melanocytic lesions the granularity tends to be finer and focally distributed.
These areas should not be chosen for sectioning when grossing a suspected melanoma as they may reveal non-diagnostic features or underestimate the Breslow thickness.