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Case Reports in Surgery
Volume 2017, Article ID 9865672, 3 pages
Case Report

A Large Lumbar Adnexal Neoplasm Presenting Characteristics of Eccrine Poroma and Poroid Hidradenoma

1Department of Anatomy, Faculty of Medicine, National and Kapodistrian University of Athens, Athens, Greece
21st Department of Surgery, Faculty of Medicine, National and Kapodistrian University of Athens, Athens, Greece
3Red Cross Hospital, Athens, Greece
4Laboratory of Experimental Surgery and Surgical Research, University of Athens Medical School, Athens, Greece
5Department of Forensic Medicine and Toxicology, National and Kapodistrian University of Athens, Athens, Greece

Correspondence should be addressed to Theodore Troupis; moc.liamg@sipuortt

Received 17 March 2017; Accepted 15 August 2017; Published 19 September 2017

Academic Editor: Imran Hassan

Copyright © 2017 Adamantios Michalinos et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Poroma is a rare benign neoplasm that derives from eccrine sweat glands epithelium. Its histological subtypes, with respect to its position within skin layers, are eccrine poroma, hidroacanthoma simplex, poroid hidradenoma, and dermal duct tumor. Poromas commonly exhibit benign clinical behavior as they are usually small and asymptomatic and do not exhibit malignant behavior. Although their histological subtypes share similar histological characteristics, they rarely coexist in the same tumor. In this report we present the case of an unusual poroma in terms of histological and clinical behavior as it was large and presented histological characteristic of both eccrine poroma and poroid hidradenoma. Coexistence of different histologic subtypes in the same tumor indicates simultaneous tumorigenesis, differentiation from one cell type to another, or parallel differentiation from a common progenitor cell. Implications in treatment remain unknown partly due to the rarity of such cases.