Extra Mammary Paget's Disease: A Rare Case Report.

Extramammary Paget's disease is a marginated plaque resembling Paget's disease but occurring in anogenital area, axilla or most commonly on the vulva. A 62-year-old postmenopausal woman presented with extremely pruritic plaque on the perineal skin which progressed gradually over 3 years and did not respond to any topical/systemic steroids, antibiotics, and antifungals. Examination revealed 7 × 8 cm. hypertrophic, verrucous plaque with erosions, and crusts at places. There was no evidence of visceral malignancy. Biopsy showed Paget's cells which were positive for Periodic Acid Schiff and alcian blue stain. Surgical excision was done considering the premalignant potential.

What was known?

EMPD is known to occur on the vulva, anogenital area and the axillary region.

Introduction

Extramammary Paget's disease (EMPD) is a marginated plaque resembling Paget's disease but occurring in anogenital area, axilla, or most commonly on the vulva. We report a case in 62-year-old menopausal woman with lesions occurring on the perineal area.

Case Report

A 62-year-old postmenopausal married woman presented with slow-growing extremely pruritic plaque on the perineal skin. It initially started as a small pruritic papule which enlarged gradually to the present size in 3 years. There was no history of bowel or bladder disturbances. There was no history of sexually transmitted infection and diabetes mellitus. On the basis of clinical presentation, she was diagnosed as a case of lichen simplex chronicus and started on topical medications and antihistamines. There was no response to any topical/systemic steroids, antibiotics, and antifungals. General and systemic examination revealed no abnormality.

Dermatological examination revealed approximately a 7 × 8 cm well-marginated, hypertrophic, and verrucous plaque in the perineal region. [Figure 1] At places grayish crusts with shallow erosions and a purulent discharge was seen. [Figure 2] There was no similar lesion anywhere else on the body. Proctoscopy examination was within normal limits. There was no regional lymphadenopathy.

Figure 1

Lesion on perineal area

Figure 2

Erosions and crusts over the plaque

A part of the plaque was excised for histopathological evaluation. Hematoxylin and eosin staining of the biopsy from the lesion showed large round cells with ample pale-staining cytoplasm, pleomorphic nuclei, and occasional prominent nucleoli, indicative of Paget cells. Inflammatory infiltrate with invasion of Paget's cells into the dermis at places was seen [Figure 3]. Cells were positive for PAS lying singly and in clusters also seen infiltrating along the skin appendages [Figure 4].

Figure 3

Paget's cells in H and E stain ×10

Figure 4

Paget's cells in PAS stain ×40

Gynaecological examination and mammography was normal. Laboratory investigations were normal. Ultrasonography of abdomen-pelvis, Magnetic resonance imaging and computerized tomography scan of the abdomen did not reveal any intraabdominal mass or retroperitoneal lymph nodes. Hence, there was no evidence of visceral malignancy.

The patient was then referred to an oncosurgeon who performed a surgical excision considering the premalignant potential of the disease. The patient followed up 1 month after the surgery with no recurrence and lymphadenopathy. She was lost for follow-up later.

Discussion

EMPD is a considered as uncommon cutaneous intraepithelial adenocarcinoma involving the epidermis and extending into the dermis. It was first described by Crocker in 1888.[1] EMPD has predilection for areas with high-density apocrine glands. It commonly occurs on the vulva and the perineum.[2] EMPD of the external genitalia and perineal skin may be associated with bladder, urethra, prostate cancer, or colorectal neoplasia.[3] Due to such associations, a complete investigation for an underlying carcinoma should accompany every confirmed diagnosis of EMPD.[4]

Etiology is not clearly known. It occurs more in women and starts usually in the fifth decade or thereafter.[5]

The patients present with pruritus, bleeding, oozing, tenderness, painful burning sensation, or hypopigmented/eczematous lesions. The hallmark is relentless progression despite topical therapy and the sharp-raised margin.[2]

Three patterns of EMPD are accepted: (1) In situ epithelial form without carcinoma and excellent prognosis, (2) epithelial form with adnexal carcinoma, and (3) with visceral malignancy.[6]

The characteristic histology of EMPD is Paget's cells, having abundant pale staining cytoplasm and large atypical nuclei with distinct intraepithelial mucus-secreting neoplastic proliferative cells. Staining of Paget's cells is done by colloidal iron, alcian blue, mucicarmine E and PAS stains. Immunohistochemical assessment can be done by markers like epithelial membrane antigen, carcinoembryonic antigen (CEA) and GCDFP-15. Cytokeratin 7 and 20 are positive and helpful for the diagnosis of EMPD. S-100 and HMB 45 is used to differentiate it from malignant melanoma in situ.

Differential diagnosis includes neurodermatitis, periorificial tuberculosis, lichen simplex, psoriasis, lichen planus, mycosis fungoides, Bowen's disease and seborrheic dermatitis.[6] Histopathologically, the differential diagnosis includes pagetoid Bowen's disease and pagetoid malignant melanoma in situ.[7]

Due to lack of knowledge about the disease and no specific guidelines for diagnosis, the treatment is difficult. The main stay of treatment considered is surgery. Wide excision surgery and Moh's surgery is routinely performed.[8] Radiotherapy, medical therapy with 5-FU, bleomycin, and CO2 laser ablation are other modes of treatment.[89] Imiquimod used topically for a localized lesion of EMPD has shown promising results with 8-16 weeks of therapy with lifelong follow-up.[10]

Surgical excision has good prognosis.[2] Recurrence seen with surgical excision is 30-60%. Moh's surgery is most effective and has a recurrence rate of 8-26%. Topical therapy helps only in few localized cases and there is a relapse rate of 50%. Associated internal malignancy or a CEA with dermal and lymphatic infiltrate of EMPD have worse prognosis.[89]

To conclude, an uncommon condition like EMPD should also be kept in mind when an elderly female presents with severe pruritic or nonspecific perineal lesion not responding to routine treatment.

What is new?

A differential diagnosis of EMPD should be considered for a severely pruritic perineal lesion unresponsive to routine treatment.