Trichilemmal Carcinoma: A Diagnostic Challenge Case Report
- 1. Dermatology Resident, Universidad Tecnológica Equinoccial. Quito, Ecuador
- 2. Department of Dermatology, Hospital Carlos Andrade Marín, Universidad Central del Ecuador, Quito, Ecuador
- 3. Department of Dermatopathology, Hospital Carlos Andrade Marín, Universidad UTE, Quito, Ecuador
Abstract
Trichilemmal carcinoma is a rare cutaneous tumor, representing only 1% of all adnexal carcinomas. It derives from the outer root sheath of the hair follicle. Clinically, it manifests as a skin-colored or slightly pink papule in sun-exposed areas in elderly patients. The following is a case report detailing trichilemmal carcinoma arising from a previous lesion and its correlation with histopathology.
Keywords
• Trichilemmal carcinoma
• Adnexal tumor
CITATION
Caceres P, Cabrera F, Posso V, Basantes A, Felix C, et al. (2024) Trichilemmal Carcinoma: A Diagnostic Challenge Case Report. J Dermatolog Clin Res 12(1): 1159.
ABBREVIATIONS
ORS: Outer Root Sheath; UV: Ultraviolet; TC: Trichilemmal Carcinoma.
INTRODUCTION
Trichilemmal carcinomas are uncommon adnexal neoplasms that are malignant and separate from the hair follicle’s Outer Root Sheath (ORS) [1]. Its incidence rate is unknown; however it is an extremely uncommon tumor [2].
The most common place for these tumors is the face, although they also commonly occur in older people on sun-exposed parts of the head and neck. There is a slight male predominance with a mean diagnostic age of 70 years [1]. Another characteristic of TC is its slow clinical progression. Generally speaking, TC is treatable with surgery, such as a broad surgical excision. While specific clinical features of TC are often overlooked, medical attention becomes necessary when an abrupt development phase ensues during the later stages of the disease’s course [3]. It can replicate as keratoacanthoma, malignant pylomatricoma or trichoblastic carcinoma, basal or squamous cell carcinoma, or a pilar tumor that is growing [4]. Known risk factors include immunosuppression, a history of burns or other local trauma, Ultraviolet (UV) and ionizing radiation, and hereditary diseases such as Cowden disease and xeroderma pigmentosa [1]. The absence of a granular layer between the stratum spinosum and stratum corneum in a tumor exhibiting trichilemmal keratinization is the primary histological characteristic that distinguishes a TC from other types of tumors [5].
CASE PRESENTATION
We report a 53-year-old female patient who 20 years ago came with a skin lesion consistent with lipoma; the lesion appeared to disappear following surgical excision and the ruling out of cancer. The tumor recurred years later in the same anatomical position, this time with a nodular lesion and an erythematous-violaceous patch on its surface. Wide surgical excision was performed, and histology reported a hair-follicle derived tumor that was growing and had distinct surgical margins. Seven years later, a localized cutaneous disease characterized by a 6 cm erythematous-violaceous, indurated, deeply adherent neoformation appeared in the patient’s left subscapular region (Figure 1).
Figure 1: Clinical images of neoformation with an erythematousviolaceous patch on its surface.
Histologically, the diagnosis of trichilemmal carcinoma was supported by several infiltrative lobules containing squamous cells and a few anucleate basaloid cells producing keratin masses without a granular layer (Figure 2).
Figure 2: Trichilemmal keratinization
Following this, a “reading-man” flap technique was used to close the large surgical excision in two stages, with periodic imaging controls in between.
DISCUSSION
Headington originally defined trichilemmal carcinoma as “a clear cell neoplasm of adnexal keratinocytes that is in continuous with the epidermis and/or follicular epithelium and is histologically invasive and cytologically atypical” in 1976 [6]. Trichilemmal carcinoma’s pathophysiology is still unknown, although known risk factors include UV radiation, solid organ transplantation, immunosuppression, ionizing radiation, burns, prior trauma or scarring, and genetic disorders (xeroderma pigmentosum and Cowden disease). Anecdotal evidence suggests that p53 suppresses the immune system during the malignant transformation of trichilemmal carcinomas [7].
The clinical presentation varies and lacks specificity. Grossly papular, nodular, or exophytic appearances are all possible in trichilemmal carcinomas. It may imitate keratoacanthoma, malignant pilomatricoma or trichoblastic carcinoma, basal or squamous cell carcinoma, or a growing pilar tumor [8].
The tumor displays dermal invasion and trichilemmal keratinization with an abrupt or pagetoid interface. Trichilemmal carcinoma cells exhibit high mitotic indices and unusual nuclei, in contrast to trichilemmomas [9].
In our case, the patient presented with multiple risk factors, notably fair skin type, prolonged exposure to UV radiation, and a clinical lesion located over a prior scar with a history of proliferating trichilemmal tumor [8]. Histologically, the presence of non-invasive margins is pivotal in assessing the potential for a locally aggressive pattern and the risk of local recurrence [10].
CONCLUSIONS
Trichilemmal carcinoma is a rare neoplasm that seldom metastasizes. Its differential diagnosis includes squamous cell carcinoma, keratoacanthoma, and amelanotic melanoma. Recurrence is uncommon, but patients should undergo regular surveillance examinations to detect any sequelae.
