Perianal extramammary paget's disease associated with primary linitis plastica of the rectum: Report of a case

We report herein a case of perianal extramammary Paget's disease associated with primary linitis plastica of the rectum. An 82-year-old woman was admitted to our hospital for investigation and treatment of a perianal eczematous lesion. A skin biopsy of the lesion revealed perianal extramammary Paget's disease and a barium enema demonstrated diffuse narrowing with an irregular contour at the ampulla recti. Under a suspected diagnosis of linitis plastica of the rectum, an abdominoperineal resection was performed to resect both the rectal and perianal lesions with regional lymphadenectomy. Grossly, marked narrowing and wall thickness were observed at the lower rectum, and a histological diagnosis of signet ring cell carcinoma was confirmed. The perianal eczematous lesion revealed many atypical cells with clear cytoplasm, being Paget cells, throughout the entire epidermis. Sparse distributions of signet ring cells were also observed in the subcutaneous tissue beneath the perianal eczematous lesion. The pathogenesis of perianal extramammary Paget's disease in this patient was therefore considered to be an intraepidermal extension of primary linitis plastica of the rectum.

Ultrastructural study of extramammary Paget's disease -- histologically showing transition from bowenoid pattern to Paget's disease pattern.

Histological, immunohistochemical, and ultrastructural studies were performed on two cases of histologically unusual extramammary Paget's disease. Histologically, the central area of the lesions showed a bowenoid pattern, and the peripheral area showed typical extramammary Paget's disease. The transition zone showed an intermediate pattern. All these areas were positive for CEA and EMA, and negative for S-100 protein. Ultrastructurally, in the intermediate pattern, the tumour cells had abundant cytoplasmic glycogen, and the widened intercellular spaces contained numerous glycogen particles, which were probably secreted by the tumour cells. It is well known that eccrine glands, but not apocrine glands, secrete glycogen particles. Therefore, the present findings suggest that some cases of extramammary Paget's disease are a proliferation of germinative cells with eccrine gland differentiation.