Urachal duct remnant-like umbilical clear cell acanthoma in an infant: an unusual presentation and pitfall in clinical practice.Int J Dermatol. 2007 Jun;46(6):615-8.

BACKGROUND: Although an umbilical nodule is common in neonates and young infants, an umbilical nodule of poor therapeutic response will increase the likelihood of other uncommon etiology. Clear cell acanthoma (CCA) has never been described as an oozing umbilical nodule on infants. METHODS: To present a case of CCA which occurred on an 8-month-old female infant presenting with one weeping nodule on the umbilicus since early neonate. The lesion underwent skin biopsy and subsequent hematoxylin-eosin and periodic acid-Schiff staining. RESULT: Three courses of liquid nitrogen cryosurgery were performed after the diagnosis of CCA was confirmed. The lesion resolved rapidly. CONCLUSION: This report presents the first and youngest case of umbilical CCA in the English literature. This case supports the inflammatory dermatosic nature of CCA.

Melanocytes in clear cell acanthoma.Am J Dermatopathol. 1990 Aug;12(4):373-6.

The presence of melanocytes in 11 clear cell acanthoma cases was investigated by silver impregnation. Melanocytes were always present, their density showing great variability from case to case and within each individual neoplasm. The possible existence of a pigmented counterpart to clear cell acanthoma is discussed.

Clear-cell acanthoma.Hautarzt. 1977 Sep;28(9):456-62.

The basis for this review forms a series of 20 new cases of clear cell acanthomas and the literature on this subject. The clinical and histopathological characteristics of this not too rare skin tumor and newer histochemical and electron microscopical findings are discussed. Particular attention will be paid to the question of the position of the clear cell acanthomas within the group of intraepidermal acanthomas and the "clear-celled" tumors of the skin. Presently, the clear cell acanthoma can be classified as a benign epidermal tumor of unknown etiology. It is assumed that the clear cell acanthoma arises through a special disturbance of the differentiation of keratinocytes.