Congenital spitz nevus.

BACKGROUND: Congenital Spitz nevus has been reported previously in the literature, but the histopathologic features have not been examined in detail. OBJECTIVE: To histologically examine and report on congenital Spitz nevus. METHOD: We examined 10 clinically submitted congenital melanocytic nevi that were histopathologically identified as congenital Spitz nevi and compared them to the characteristics seen in acquired Spitz nevus and superficial congenital melanocytic nevus. RESULTS: Of the 10 congenital Spitz nevi, 9 were compound and 1 was dermal. Two showed features of combined Spitz nevus (Spitz and blue). Six cases showed all 16 listed characteristics of acquired Spitz nevus, with two cases having 15 and two cases having 14 characteristics. Of the superficial congenital melanocytic nevus characteristics, all except three cases had all 12 attributes. The one dermal lesion had all the characteristics of the acquired Spitz nevus and all but one of the characteristics of the superficial congenital melanocytic nevus in regards to intradermal findings. CONCLUSIONS: Congenital Spitz nevi are true congenital lesions, with histopathologic features of both acquired Spitz nevus and superficial congenital melanocytic nevus.

Cutaneous squamous cell carcinomas consistently show histologic evidence of in situ changes: a clinicopathologic correlation.

Squamous cell carcinoma on sun-damaged skin is a malignant neoplasm that evolves from its inception as squamous cell carcinoma in situ, which is commonly referred to as an actinic keratosis. In this study, we reviewed 1011 squamous cell carcinomas on sun-damaged skin and found that nearly 100% of these lesions contained histopathologic changes consistent with squamous cell carcinoma in situ at the periphery or within the confines of the squamous cell carcinoma. These malignant changes began in single layer areas of the lower epidermis and evolved into the epidermis and dermis.

Superficial congenital compound melanocytic nevus. Another pitfall in the diagnosis of malignant melanoma.

METHODS: We reviewed the histology of 42 superficial congenital compound melanocytic nevi and found features that simulate malignant melanoma. In some, there were asymmetry and poor circumscription, an increased number of single melanocytes, which predominated over nests of melanocytes in some high power fields, single melanocytes were not equidistant from one another, scatter of single melanocytes was above the dermoepidermal junction, and there was confluence of nests of melanocytes, which are features in common with a malignant melanoma. RESULTS: Fifty-six percent of the cases had three to four criteria present, and 92% of the cases had three to six criteria present. The mean age of the patients at the time of biopsy was 20 years, and the mean size of the nevus at time of biopsy was 1.7 cm. CONCLUSIONS: Appreciation that simulation of a melanoma in situ by the epidermal component of a superficial congenital compound melanocytic nevus in older children and adults is an expected finding and may be similar to congenital nevi biopsied shortly after birth has not been emphasized. Awareness of these simulants may prevent misinterpretation of a benign superficial congenital compound melanocytic nevus as a malignant melanoma.