毛囊囊肿是一种犬常见的皮肤疾病，通常为单个的皮内隆起，内含上皮衬里的非瘤性囊肿组织。本文介绍了一例相关病例，该病例较特殊，肉眼病变为全身性分布，大多数囊肿表面光滑无对外开口，切开之后可挤出干酪样物。组织病理检查发现大部分囊肿之周边有一局部缺口，囊壁内衬多层扁平上皮，有颗粒层角化和偶尔无颗粒层角化，亦无毛发结构，囊腔含少量层状角质及不完全角化的有核细胞或后续钙化，囊肿周围之组织大多无炎症反应，显示并无毛囊破裂、内容物外溢之处。本毛囊囊肿之特点有三：1) 广泛地全身性分布为本病例所特有。2) 囊壁之大部分有颗粒层之角化，囊壁之局部缺口疑似企图形成对外开口，与漏斗型囊肿类似。3) 囊壁表面无开口及偶有局部骤然性角质化与峡型囊肿类似。由于该病例在临床表现、病例特征和常见的几种类型的毛囊囊肿均有不少差异，故拿出来和兽医同仁分享。
Hair follicle cysts are the most
common non-neoplastic skin diseases in canine. This article reports an
exaggerated form of hair follicle cyst with extensive body-wide distribution.
Grossly, numerous protruding intracutaneous cysts, most without pore openings,
distributed throughout the body. On dissection, caseous materials were
expressed from the cysts. Histologically, cysts walls were lined by stratified
squamous cells with stratum granulosum, with a focal attenuation in the wall
mimicking a fail attempt to form pore opening, and without recognizable hair
fragments. The cyst lumens contained a small amount of laminated keratin and
nucleated keratinized cells with subsequent mineralization. Multifocally,
keratinization occurred without the formation of stratum granulosum
characteristic of tricholemmal cornification. There was usually no
peri-follicular dermal inflammation, excluding the concern of leaking cystic
contents inciting granulomatous inflammation. These cysts were apparently hair
follicle originated having 3 distinctive features: 1) The extensive
distribution of follicular cysts throughout the body is unique to this case. 2)
The gradual keratinization and the failure to form pore opening mimic
infundibular cyst. 3) The “no” pore openings and occasional abrupt
keratinization mimics isthmus cyst. We believe it is worthy to share this
unique case with colleagues in the veterinary community.
References
[1]
Goldschmidt, M.H., et al. Surgical Pathology of Tumors of Domestic Animals, Vol. 1, Epithelial Tumors of the Skin. Davis-Thompson DVM Foundation, Gurnee, IL, 200-217.
[2]
Hargis, A.M. and Myers, S. (2017) Chapter 17. The Integument. In: Zachary, J.F., Ed., Pathologic Basis of Veterinary Disease, 6th Edition, Elsevier, St. Louis, MO, 1009-1146.
