Proliferating trichilemmal cyst: The value of ki67 immunostaining

Abstract

Background:A proliferating trichilemmal cyst (PTC) is an uncommon, rapidly-reproducing cutaneous epithelial cyst, differentiating from the isthmic portion of the outer hair root sheath. It is usually described as a benign tumor, but malignant transformation has been reported and is then denominated as a malignant proliferating trichilemmal tumor. Ki67 immunostaining has been used as a methodology for the evaluation of tumor grade in other tumors, due to its distinctive reaction patterns which exclusively involve proliferating cells.Objectives:(1) To report the incidence of cases of PTCs in a General Hospital during a 12 years period. (2) To determine the expression of ki67 using immunohistochemical staining. (3) To correlate ki67 reaction patterns with clinical prognosis.Materials and Methods:The dermatology department's files during a period of 12 years were reviewed; cases with a diagnosis of PTC were selected, and ki67 immunostaining was done when enough biological material was available.Results:A total of 15 cases with a diagnosis of PTC were identified. In 12 cases, ki67 immunostaining was carried out. In 9 of the 12 cases, ki67 was observed in the basal cells of the cystic epithelium, one case was moderately positive in palisading epithelial cells; in the other two cases ki67 immunostaining was negative. Clinical follow-up was done and revealed that no patient had local recurrence in 5 years after surgical removal of PTC. We therefore consider this immunostaining technique is probably correlated with low recurrence potential.

A proliferating trichilemmal cyst in the perianal region: A case report

“…Study of the mitotic count using the Ki-67 index is one option because a high cell proliferation rate is associated with malignancy. Moreover, changes in glycoprotein of accession CD34 and mutations in the p53 suppressor gene may also be related, as well as progression of the lesion to squamous cell carcinoma [ 7 , 9 , 10 ].…”

Extensive and ulcerated malignant proliferating trichilemmal (pilar) tumour, arising from multiple, large, degenerated trichilemmal (pilar) cysts

“…Areas of trichilemmal keratinisation and focal epidermal keratinisation are typically present 7. Other potential features include vacuolated or clear glycogen-rich cells, cytological atypia of different degrees, squamous eddies, keratin pearls, focal cystic areas and calcifications 2 12 13. The peripheral cells tend to palisade and mitotic rate is generally high 2 14.…”

A Rare Cutaneous Adnexal Tumor: Malignant Proliferating Trichilemmal Tumor

“…Immunohistochemical studies have also been conducted for the diagnosis and differential diagnosis of PTTs and morphological descriptions [ 2 , 7 – 9 ]. Immunohistochemical indicators, such as Ki-67, P53, and CD34, have been given much focus [ 2 , 7 – 9 ]. Increased staining with Ki-67 and P53 was observed when MPTT cases were compared with PTT cases in these studies [ 2 , 8 ].…”

“…Increased staining with Ki-67 and P53 was observed when MPTT cases were compared with PTT cases in these studies [ 2 , 8 ]. Ki-67 expression was approximately 20% to 40% in MPTTs, whereas Ki-67 expression was below 5% at the basal layer level in PTTs [ 2 , 8 , 9 ]. The expressions of Ki-67 and P53 at 20% and 80%, respectively, in our case support the literature findings.…”