|
 |
| LETTER TO EDITOR |
|
| Year : 2019 | Volume
: 11
| Issue : 6 | Page : 258-259 |
|
|
Proliferating trichilemmal cysts: A clinicopathological study of 14 cases
Pablo Vargas-Mora1, Diego Orlandi1, Claudia Morales2, Irene Araya1
1 Department of Dermatology, Faculty of Medicine, University of Chile, Santiago, Chile
2 Dermopathology Section, Pathology Service, University of Chile Clinical Hospital, Santiago, Chile
| Date of Web Publication | 14-Jan-2020 |
Correspondence Address:
Dr. Pablo Vargas-Mora
Department of Dermatology, Faculty of Medicine, University of Chile, Santiago
Chile
 Source of Support: None, Conflict of Interest: None  | Check |
DOI: 10.4103/ijt.ijt_112_19
How to cite this article:
Vargas-Mora P, Orlandi D, Morales C, Araya I. Proliferating trichilemmal cysts: A clinicopathological study of 14 cases. Int J Trichol 2019;11:258-9 |
Sir,
Proliferating trichilemmal (pilar) cysts (PTCs) are a rare dermal neoplasm, usually benign, but with locally invasive and even metastatic potential. First described by Wilson-Jones in 1966, it consists of a scalp lesion with similar pathologic features to squamous cell carcinoma (SCC) in an elderly patient.[1],[2] Subsequently, these tumors were given multiple denominations, such as invasive pilomatrixoma, trichoclamidocarcinoma, subepidermal acanthoma, and giant hair matrix tumor, among others.[2] This makes it difficult to determine its true incidence. They may arise de novo or in a preexisting cystic lesion, and based on few case reports, it is three to four times more common in women, usually seen in elderly patients, and located in up to 85% of cases on the scalp.[1],[2],[3]
The objective of this study was to evaluate the clinical and histopathological characteristics of patients with PTC in a group of latin patients. We performed a retrospective, observational study in the Dermatology and Pathology departments of a Chilean university hospital. Using the pathology department database on all skin biopsies with a pathological diagnosis of PTC between 1995 and 2018, the biopsy slides were reviewed again by a dermatopathologist to confirm the diagnoses. Sex, age, clinical diagnosis, location, and histopathological diagnosis were analyzed.
A total of 14 patients were included [Table 1]; 9 (64.3%) were female, with an average age of 56 years (±20.9, range: 16–85 years). The clinical diagnoses were nonspecific tumor = 6 (43%), epidermal cyst = 3 (21.4%), trichilemmal cyst = 3 (21.4%), pilomatrixoma = 1 (7.1%), and atypical nevus = 1 (7.1%). The tumors were located on the scalp in 11 cases (78.7%), hand in 1 case (7.1%), elbow in 1 case (7.1%), and thigh in 1 case (7.1%) [Figure 1]. Eleven (78.7%) lesions corresponded to PTC [Figure 2]a, 2 (14.2%) to hybrid proliferating cysts with epidermoid and trichilemmal components, the latter being predominant, and 1 (7.1%) to a PTC with moderately differentiated intracystic SCC [Figure 2]b and [Figure 2]c. | Table 1: Clinical and histopathological characteristics of patients presenting with proliferating trichilemmal cysts
Click here to view |
 | Figure 1: (a) Proliferating trichilemmal cyst on the scalp (arrow) with multiple trichilemmal cysts. (b) Proliferating trichilemmal cyst in elbow
Click here to view |
 | Figure 2: (a) Cyst with hyperkeratosis and squamous proliferation (H and E, ×20). (b) Proliferating trichilemmal cyst with squamous cell carcinoma (H and E, ×40). (c) Malignant squamous proliferation with marked cellular pleomorphism, hyperchromasia, and mitotic figures (H and E, ×400)
Click here to view |
The present study is the first report on this rare entity in Latin patients and showed a younger age of presentation compared to previously reported series, with a female predominance and a higher incidence on the scalp, which correlates with features described on the available medical literature.[1],[3] It also highlights the presence of two proliferating cysts of the trichilemmal–epidermal hybrid type, which, according to the available evidence, there are no reported cases of proliferative epithelial cysts with both components.[4] Consequently, when evaluating these lesions, it is necessary to distinguish if there are areas with a granular layer, which defines the epidermoid component and therefore the diagnosis of hybrid proliferative cysts. Furthermore, we report the case of an intracystic SCC, since the malignant transformation arising within a cutaneous cyst is a very rare but described phenomenon.[3],[5]
Further studies with larger sample size, possibly multicenter, and more extensive clinical evaluation will help to better understand the clinical behavior of this pathology, in specific populations.
Financial support and sponsorship
Nil.
Conflicts of interest
There are no conflicts of interest.
 References | |  |
| 1. | Ye J, Nappi O, Swanson PE, Patterson JW, Wick MR. Proliferating pilar tumors: A clinicopathologic study of 76 cases with a proposal for definition of benign and malignant variants. Am J Clin Pathol 2004;122:566-74.  |
| 2. | Folpe AL, Reisenauer AK, Mentzel T, Rütten A, Solomon AR. Proliferating trichilemmal tumors: Clinicopathologic evaluation is a guide to biologic behavior. J Cutan Pathol 2003;30:492-8. |
| 3. | Satyaprakash AK, Sheehan DJ, Sangüeza OP. Proliferating trichilemmal tumors: A review of the literature. Dermatol Surg 2007;33:1102-8. |
| 4. | Chang RS, Yao XF, Wu YH. Spectrum of hybrid cysts and their clinical significance. Am J Dermatopathol 2018;40:397-400. |
| 5. | Kim UG, Kook DB, Kim TH, Kim CH. Trichilemmal carcinoma from proliferating trichilemmal cyst on the posterior neck. Arch Craniofac Surg 2017;18:50-3. |
[Figure 1], [Figure 2]
[Table 1]
|
