Clear cell papulosis: an immunohistochemical study to determine histogenesis

Clear Cell Proliferations of the Skin: A Histopathologic Review

ABSTRACT

Cutaneous clear cell proliferations encompass a heterogenous group of several primary cutaneous neoplasms and metastatic tumors with different histogenesis. Many of these clear cell proliferations may seem strikingly similar under the microscope resulting in challenging diagnosis. In many of these clear cell lesions, the reason for the clear or pale appearance of proliferating cells is unknown, whereas in other ones, this clear cell appearance is due to intracytoplasmic accumulation of glycogen, mucin, or lipid. Artifacts of tissue processing and degenerative phenomenon may also be responsible for the clear cell appearance of proliferating cells. Awareness of the histopathologic findings as well as histochemical and immunohistochemical techniques are crucial to the accurate diagnosis. This review details the histopathologic features of clear cell cutaneous proliferations, classifying them according their type of differentiation and paying special attention to the histopathologic differential diagnosis among them.

Extramammary Paget disease of the vulva

Extramammary Paget disease (EMPD) is a rare neoplasm with uncertain histogenesis, usually presenting in the anogenital area, most commonly in the vulva. The disease is characterized by slow grow and high recurrence rates. This article reviews the epidemiological, clinical, morphological, genetic and treatment features of EMPD of the vulva reported in recent years.

Clear cell papulosis: Dermatoscopic findings and literature review

Clear cell papulosis is a rare skin condition that predominantly develops in patients of Asian background during their early childhood. We present a new case of clear cell papulosis of a 1-year-old Thai girl presented with multiple hypopigmented macules and papules on the lower abdomen and pubic area for 3 months and also review the previous 41 cases published in the literature since 1987. Herein, for the first time, we report the dermatoscopic features of clear cell papulosis that represents as depigmented homogenous structureless lesions. This would be beneficial for distinguishing clear cell papulosis from its differential diagnoses.

Lesions of anogenital mammary-like glands: an update

Long considered to be ectopic breast tissue representing the caudal remnants of the milk ridges, anogenital mammary-like glands are nowadays thought to represent a normal constituent of the anogenital area. Lesions involving these glands, benign or malignant, epithelial or stromal manifest a striking similarity to their mammary counterparts. This review addresses the recent literature on lesions of anogenital mammary-like glands and our personal experience with various lesions related to these structures. Discussed are the normal anatomy and histology of these glands as well as the clinical presentation, histopathological and immunohistochemical features, molecular biological aspects, and differential diagnosis of various lesions involving anogenital mammary-like glands, including lactating adenoma, hidradenoma papilliferum, hidradenocarcinoma papilliferum, fibroadenomas, phyllodes tumor, pseudoangiomatous stromal hyperplasia, extramammary Paget disease, and other carcinomas. In addition, "nonspecific" epithelial or stromal changes some of which can be likened to similar changes occurring in a range of benign breast disease, including sclerosing adenosis, columnar cell lesions, ductal lesions and various metaplastic changes affecting epithelium and myoepithelium are discussed. Although lesions of anogenital mammary-like glands are often discussed in many dermatopathology textbooks in the context of cutaneous adnexal neoplasms we advocate that the best approach to the diagnosis of these lesions is to relate them to analogous well recognized lesions occurring in the breast, that is, through the eyes of a breast pathologist. This will enable their recognition, precise classification and should introduce greater uniformity in how they are reported in the literature so that more meaningful clinicopathological comparisons and correlations may be made.

Clear Cell Papulosis of the Skin: A Case Report From Singapore

Clear cell papulosis of the skin is a rare condition; to our knowledge only 12 cases have been reported. Here, we report for the first time a case of clear cell papulosis with cytokeratin 7 expression and provide a comprehensive literature review. A 16-month-old girl presented with 3 hypopigmented lesions in the pubic region that were 3 to 9 mm in diameter; 1 lesion was papular, and the other 2 were macular. A skin biopsy revealed acanthosis with a proliferation of clear cells along the basal and suprabasal layers of the epidermis occurring in small clusters and singly. The cells had round to oval regular nuclei with abundant to moderate lightly eosinophilic to clear cytoplasm and intracytoplasmic mucin. Immunostaining produced positive results for carcinoembryonic antigen, AE1/3, epithelial membrane antigen, cell adhesion molecule 5.2, and cytokeratin 7 and negative results for gross cystic fluid disease protein, S100, and HMB-45. Clear cells of clear cell papulosis are mucin-positive and S100-negative glandular-secretory epithelial cells with histogenetic features of Toker cells of nipple and Paget cells. Immunohistochemical features support an eccrine secretory cell origin because the clear cells are consistently and strongly positive for carcinoembryonic antigen, positive for cell adhesion molecule 5.2, and negative or rarely positive for gross cystic fluid disease protein.