Mitsui Y, Ogawa K, Koga K, Goto K, Takai T, Anan T, Fukumoto T, Asada H. Trichilemmal cysts with proteinaceous material: A potential diagnostic pitfall.
J Cutan Pathol 2022;
49:515-524. [PMID:
35166386 DOI:
10.1111/cup.14214]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Revised: 01/08/2022] [Accepted: 02/10/2022] [Indexed: 11/28/2022]
Abstract
BACKGROUND
Cysts of the skin are observed frequently and their diagnoses are generally straightforward. However, atypical cystic lesions for which differentiation is indistinct have been noted.
METHODS
We examined five cases of trichilemmal cyst with proteinaceous material (TCPM), which required differentiation from sweat duct/gland tumors. We investigated the histopathological findings of TCPMs and evaluated the immunohistochemical expression of cytokeratin (CK) 10, CK13, CK17, CK19, CD8, and CD117. Immunohistochemical analysis was performed on the five TCPMs, 10 trichilemmal cysts (TCs), five clear cell hidradenomas, five poroid hidradenomas, and cutaneous normal adnexa.
RESULTS
Apoptotic cells were present in the cyst wall with a small amount of keratin or calcification in the cavity of TCPMs. The TCPMs and TCs were negative for CK19 and CD117, whereas clear cell hidradenoma and poroid hidradenoma were positive for CK19 and CD117. The restricted positivity for CK10 was detected in the suprabasal layers of the cyst walls of TCPMs and TCs. The immunostaining patterns of TCPMs and TCs were similar to those of normal follicular isthmus.
CONCLUSIONS
The histopathological findings with characteristics of TCs and a panel of immunohistochemical antibodies including CD117, CK19, and CK10 contributed to a correct diagnosis of TCPM. This article is protected by copyright. All rights reserved.
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