Malignant melanoma associated with a plaque-type blue nevus of the cheek: a case report

Abstract

Blue nevi, which are characterized by collections of pigment-producing melanocytes in the dermis, have a variety of clinicopathological characteristics. Plaque-type blue nevus (PTBN) is a variant of blue nevi. PTBN presents at birth or arises in early childhood, and it shows a combination of the features found in common blue nevus and cellular blue nevus. It is typically found on the dorsal surface of the hands and feet or on the head and neck, and it is usually benign and stable over time. However, reports have occasionally described malignant melanomas developing in or associated with a PTBN. Malignant blue nevi are most commonly found on the scalp. We report the case of an 88-year-old woman with a malignant melanoma associated with a PTBN of the cheek.

Keywords: Blue nevus; Case reports; Malignant melanoma.

Fig. 1

A blue maculo-papular confluent plaque was seen on the right cheek area.

Fig. 2

A histopathological examination showed atypical fusiform and epithelioid melanocytes containing granular or dense melanin pigment (hematoxylin and eosin stain, ×40).

Fig. 3

In the second operation, the large skin and soft tissue defect were covered by a lateral arm free flap. (A) After wide excision, a skin and soft tissue defect occurred (B) Primary closure of the donor site was performed. (C) Result at postoperative 2 months.