Case 4 Female, 82 years. Biopsy of longstanding and unchanging, 5 cm large pigmented plaque, scalpShow diagnosis & comments
Features are compatible with plaque-type blue naevus
Densely cellular blue naevi occur in the scalp region, and on very rare occasions may ultimately even spread into the skull. The presence of many pigmented dendritic melanocytes, the formation of densely cellular ill-defined nodules and the versy silimar histological appearance throughout the lesion, together with scarcity of mitotic figures, absence of atypical mitotic figures, absence of necrosis in this densely cellular lesion, and the history of a longstanding stable lesion argue against melanoma. However, with this histological picture I feel it is best to advise re-excision, in order to achieve negative surgical margins; a very few cases not unlike this one have, usually over course of many years, progressed to metastasizing melanoma. In this particular instance, however, the patient being 82 years of age, it may be that the clinician -discussing the matter with the patient- decides that it is preferable to choose wachful waiting, especially if the patient has other illnesses that are of greater concern than the chance of local recurence and progression of this melanocytic lesion.