What are nevus cells?

Although the term "nevus cell" was introduced nearly a century ago and is used daily in the parlance of general pathology and dermatopathology, writings about the subject indicate that agreement has yet to be reached about the nature of these cells. On the basis of all of the evidence about "nevus cells," morphological and biochemical, that has been accumulated to date, we conclude that they are simply melanocytes.     

Spitz nevus or melanoma?

Spitz nevi are benign melanocytic neoplasms of children and young adults that can be exceedingly difficult to distinguish from malignant melanomas. Although a nearly definite diagnosis can be made in most cases, the histological distinction between Spitz nevi and melanomas is equivocal in about 6% to 8% of cases. In those cases, and perhaps even with presumed benign Spitz nevi, clear surgical margins are desirable. The most helpful differentiating features of Spitz nevi are patient age, sharp demarcation, symmetry, maturation of melanocytes at the base, and epithelial hyperplasia. None of these criteria are completely reliable, and multiple other criteria must be considered as well.     

Hidrocistoma apocrino sobre nevus sebáceo

A 41-year old woman, who had a congenital sebaceous nevus on the scalp, developed an apocrine hidrocystoma. This tumor, also known as apocrine cystadenoma or more recently as apocrine gland cyst, is a rare lesion, in most cases solitary, that occasionally arises from sebaceous nevi.Most tumors arising from sebaceous nevi appear in adults and often have a non agresive behaviour. Currently the prophylactic removal of sebaceous nevi is not adviced and clinical follow-up is probably enough, with surgical excision only of new developing lesions.     

Nevus marginatus: a distinct type of epidermal nevus or merely a variant of nevus sebaceus?

Epidermal nevi (EN) represent a heterogeneous group of mosaic skin lesions frequently following the lines of Blaschko. They are divided into organoid and nonorganoid types. Herein we report on a 35-year-old man with a rather unusual type of EN. A linear lesion involving the trunk and following Blaschko's lines was conspicuously bordered by dark brown papules. The flat reddish central area histopathologically showed sebaceous hyperplasia consistent with nevus sebaceus, an organoid EN type, whereas the elevated margin showed features of a common nonorganoid keratinocytic EN. For this peculiar disorder, we propose the term 'nevus marginatus'. So far it is not clear whether nevus marginatus represents a distinct entity or merely an unusual clinical variant of nevus sebaceus.     

Port-wine-stain (nevus flammeus), congenital Becker's nevus, café-au-lait-macule and lentigines: phakomatosis pigmentovascularis type Ia--a new combination

A 16-year-old male had brown macules in a geographic pattern with increased terminal hair on the back and dusky red partially blanchable non progressing macules on his left thigh since birth. Clinical diagnoses of Becker's nevus and port-wine-stain were made and confirmed histopathologically. In addition, he had multiple lentigines on the face and trunk and a single café-au-lait-macule on his chest.     

Do you know this syndrome? Becker nevus syndrome

Patients presenting with plantar puncture wounds with presence of foreign bodies are treated in emergency departments, dermatology and orthopedic clinics. The clinical features of these lesions are rarely cited in journals and textbooks of dermatology. We report a case of foreign body in the plantar surface of the foot, in which clinical history and dermatological examination were decisive for the diagnosis.