Ulcerated sclerotic giant congenital melanocytic naevus: case report and review of the literature

Mass Spectrometry Imaging Can Distinguish on a Proteomic Level Between Proliferative Nodules Within a Benign Congenital Nevus and Malignant Melanoma

Histopathological interpretation of proliferative nodules occurring in association with congenital melanocytic nevi can be very challenging due to their similarities with congenital malignant melanoma and malignant melanoma arising in association with congenital nevi. We hereby report a diagnostically challenging case of congenital melanocytic nevus with proliferative nodules and ulcerations, which was originally misdiagnosed as congenital malignant melanoma. Subsequent histopathological examination in consultation by one of the authors (R.L.) and mass spectrometry imaging analysis rendered a diagnosis of congenital melanocytic nevus with proliferative nodules. In this case, mass spectrometry imaging, a novel method capable of distinguishing benign from malignant melanocytic lesions on a proteomic level, was instrumental in making the diagnosis of a benign nevus. We emphasize the importance of this method as an ancillary tool in the diagnosis of difficult melanocytic lesions.

Sclerotic Regressing Large Congenital Nevus

Regression of congenital nevi is usually associated with loss of pigment or halo formation. In rare cases, regression is characterized by sclerosis and hair loss. We describe a rare case of a sclerotic hypopigmented large congenital melanocytic nevus in which a localized scleroderma-like reaction process of regression seemed to have started in utero and progressed throughout early childhood.

Spontaneous Regression of a Congenital Melanocytic Nevus by Sclerosis

Congenital melanocytic nevi (CMNs) naturally evolve throughout life, growing proportionately with the child, darkening, and exhibiting textural or surface changes (e.g., papillomatous, verrucous, cerebriform), hypertrichosis, and, later in life, lightening of pigmentation. We report the case of a 5-year-old child with complete resolution of a medium-sized CMN involving the distal left leg and foot via sclerosis and in the absence of any halo phenomenon. Spontaneous regression of CMN via sclerosis is rare, and it is thought that an immunologic mechanism different from the mechanism that the halo phenomenon induces mediates this regression. We reviewed the literature on this phenomenon and discuss how it might lead to regression of the nevus.

Atrophic congenital melanocytic nevus mimicking rapidly involuting congenital hemangioma

Congenital melanocytic nevi (CMN) are benign skin lesions present in some newborns. We describe a newborn boy with a giant CMN on the scalp. It appeared as an atrophic patch with a central nodule that was suggestive of a rapidly involuting congenital hemangioma or some other vascular tumor. Histopathology confirmed the diagnosis of CMN. Magnetic resonance imaging was normal, excluding leptomeningeal melanocytosis. We did not find any other cases of CMN with this presentation in the literature.

Desmoplastic hypopigmented hairless nevus: a variant with progressive depigmentation, induration, and overgrowth

Large congenital melanocytic nevus rarely presents itself without hairs, with hardened skin and progressive depigmentation. We report a girl who presented with a large congenital melanocytic nevus in the left cheek. Over the years, the nevus became pruriginous, light brown, bumpy, and hard. Histology revealed nevus cells interspersed with dense fibrosclerotic collagen bundles. There are few reported cases of large congenital melanocytic nevus with this evolution, so-called desmoplastic hypopigmented hairless nevus.