Bladder cell nevus D22.L

Only histologically diagnosable special form of a melanocytic nevus. Characteristic feature are distended, bright, ballooned melanocytes, mostly without pigment formation. Extremely rare is the development of a malignant melanoma at the base of a bladder cell nevus ( bladder cell melanoma).

It is predominantly a compound type melanocytic nevus with symmetrical architecture and a sharp border to the surrounding connective tissue. Small, round melanocytes are found in the upper part of the dermis and in the area of the junctional zone. Mostly in the middle and deep parts of the dermis, large "bubble-like" distended melanocytes with broad light or finely granulated cytoplasm and regular round nuclei are found grouped among other melanocytes or exclusively occurring there. Bubble-cellular parts can also occur in blue nevi. Malignancy ( bladder cell melanoma) must be diagnosed when a predominant nuclear polymorphism, including multinucleated giant cells, with nuclear hyperchromasia and mitoses, occurs.

Random histological findings in benign tumours. Therefore no further therapeutic measures.