Answer

Primary Extramammary Pagets disease

Diagnosis

Depending on the history, classical lesion at susceptible site, presence of classical Paget's cells in the epidermis, and in the absence of any systemic involvement, patient was finally diagnosed as a case of Primary extramammary Paget's disease (EMPD).

Review

EMPD is an uncommon neoplastic condition of apocrine-bearing skin. Lesions of EMPD typically involve the vulvar (the most common site affected), perianal, perineal, scrotal, and penile regions. Two major types of EMPD are described. In the first type called "primary" EMPD, constituting 75% cases, the disease originates in the skin either arising in situ epithelium or adnexal carcinoma. Pathogenesis of primary EMPD still remains elusive, but it is hypothesized that pluripotential germinative cells within the epidermis go awry in their attempt to form apocrine structures and result in the formation of malignant Paget's cells. ^[1],[2] In the second type "secondary" EMPD, noticed in 25% cases, contiguous epithelial spread form a visceral malignancy of either genitourinary or gastrointestinal. ^[1],[2],[3]

Most cases of vulvar EMPD are of primary type, but EMPD of the male genitalia is frequently associated with internal malignancy of genitourinary tract. Perianal EMPD, in both sexes, is associated with anal or colorectal carcinoma in 70-80% of cases. ^[1],[2],[3] However in our case, no underlying malignancy was detected, despite the lesion being on the susceptible site.

Most of the cases reported are in seventh decade although the age of presentation ranges between 50 and 80 years and females are affected more frequently than males. ^[1] The disease most commonly presents as gradually progressing, well-marginated, erythematous or leucoplakic plaques with eczematous changes, usually associated with intermittent itching, but there might be variable degree of burning, irritation, tenderness, bleeding, oozing, maceration, and swelling ^.[1] In most of the cases, there is history of progression of the lesions over months/years despite being treated with topical therapy for various clinical differentials as was noticed in our case.

The diagnosis of EMPD is based on characteristic history, typical location and morphology of the lesions, and histopathology and histochemistry findings. Histopathology reveals distinctive intraepidermal neoplastic proliferative cells (Paget's cells) with abundant pale-staining cytoplasm and large atypical nuclei. In primary EMPD, Paget's cells may be present in the outer root sheath (as in our case) and is characteristic, but are also found in sebaceous, apocrine, or eccrine gland structures. Immunohistochemical stains such as carcinoembryonic antigen, cytokeratin 3,7,20, and S-100 are helpful in diagnosing EMPD and its differentiation into primary and secondary variants. ^[1],[4]

Clinical differential diagnosis of EMPD in anogenital area includes psoriasis, lichen planus, seborrheic dermatitis, lichen simples chronicus, verruca vulgaris, periorificial tuberculosis, tuberculous verrucosa cutis, Bowen's disease, mycosis fungoides, malignant melanoma, and dermatophyte infection. Histopathological differentials include pagetoid Bowen'disease, and pagetoid malignant melanoma in situ.

Although surgical excision carries a high recurrence rate, it remains the treatment of choice for EMPD. Imiquimod is a promising therapeutic option for the treatment of limited cutaneous EMPD. Treatment-associated morbidity is minimal and self-application improves patient convenience. ^[1],[5]

Prognosis for primary intraepithelial EMPD is good when compared with the secondary EMPD.



The names of the winners(first three correct entries) are:

1. Vishal Gupta, New Delhi
2. Riti Bhatia, New Delhi
3. Vinay K, Chandigarh

"Others who have sent correct answers are mentioned below:"

Geeti Khullar, Piyush Kumar, Urmi Khanna, Ganesh Avhad, Resham Vasani, Anupama, Keshavmurthy Adya, Himanshu Gupta, Sudhir Nayak U.K., Vishal Chugh, Tirthankar Gayen, Bhavana R. Doshi, Joginder Kumar, Hari Kishan Kumar.Y., Soumyajit Roychaudhuri.