[OA-33] Histopathological and clinical study between primary adnexal carcinoma with pagetoid spreading and extramammary Paget disease

Warit Chongkolwatana1, Panitta Sittinamsuwan1, Suchanan Hanamournroongruang1, Ngoentra Tantranont1, Kanapon Pradniwat1, Thitipat Hansomwong2, Vuthinun Achariyapota3, Penvadee Pattanaprichakol4 and Voraparee Suvannarerg5

  1. Department of Pathology, Facolty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
  2. Division of Urological Surgery, Department of Surgery, Facolty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
  3. Department of Obstetrics and Gynaecology, Facolty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
  4. Department of Dermatology, Facolty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
  5. Division of Diagnostic Radiology, Department of Radiology, Facolty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand

Extramammary Paget disease (EMPD) is rare. When EMPD with invasive carcinoma is identified, primary adnexal carcinoma (PAC) is a main differential diagnosis. We aimed to compare difference of histopathology and prognosis of EMPD with invasion and PAC. Haematoxylin and eosin – stained sections of EMPD with invasive carcinoma between 2006 and 2021 were classified into PAC with pagetoid spreading and EMPD with invasion. We compared four characteristics between both entities as follows: (1) clinical presentation; (2) lymphovascolar invasion; (3) regional lymph node metastasis; and (4) distant metastasis. A total of 33 cases were recruited and classified into 10 cases of PAC with pagetoid spreading and 23 cases of EMPD with invasion. PAC included adenocarcinoma, not otherwise specified in 5/10 cases, apocrine carcinoma in 3/10 cases, hidradenocarcinoma in 1/10 cases and syringocystadenocarcinoma papilliferum in 1/10 cases. Clinical presentation of PAC was mass lesion (p-value < 0.0001). PAC presented higher lymphovascolar invasion (p-value = 0.010) and regional lymph node metastasis (p-value = 0.004). In conclusion, PAC shows worse prognosis when compared with EMPD with invasion due to higher lymphovascolar invasion and regional metastasis. Clinical history and specific histologic characteristics are needed for differentiating both diseases.

Keywords: adnexal carcinoma; extramammary Paget disease; pagetoid spreading