Extensive Facial Trichoblastoma – A Rare and Disfiguring Condition

Background

Trichoblastoma is a rare skin disease which is benign in nature. It usually presents as a papulonodular skin lesion on the head or neck. It may be confused with more common conditions such as rosacea or basal cell carcinoma. Identification of this condition is important as it may progress and become extensive, as in the present case. We present a case of an unfortunate woman who had extensive and disfiguring facial trichoblastoma for the past 30 years. This case underlines the need for referral to the appropriate specialist when a treatment is unsuccessful. It also serves as a reminder of the need for optimal exposure when examining patients, while considering the constraints of personal protective equipment use, especially during this Coronavirus Disease 2019 (COVID-19) pandemic period.

Case Report

A 62-year-old Malay woman presented to our primary care clinic for her regular hypertension and diabetes mellitus care visit. She had been diagnosed with these conditions several months earlier. Her medications were perindopril (8 mg daily), amlodipine (10 mg daily), metformin extended-release (500 mg nightly), gliclazide modified-release (30 mg daily), and atorvastatin (10 mg nightly). She did not smoke, drink alcohol, or use recreational drugs. Her family history was unremarkable except for a sister with nasal cancer diagnosed at the age of 57. This was the first time this doctor had seen her.

On examination, she wore a headscarf as a religious requirement, and a face mask, in view of the COVID-19 pandemic. Her blood pressure was 161/93 mmHg and pulse rate was 98 beats per minute, while her body mass index was 20 kg/m2.

Examination of her cardiovascular system and feet were unre-markable. During the consultation, the doctor noticed several small lumps over the patient’s eyebrows. As she removed her headscarf and mask for a thorough examination, numerous skin-colored papules and nodules were seen on her nose, nasal bridge, forehead, and around her eyebrows (Figures 1–4). No ulcers or telangiectasias were seen. These lesions were soft, non-tender, and had no hypoesthesia.

On further questioning, she said that these lesions had initially developed 30 years earlier and had gradually became more widespread. They did not affect her breathing or sense of smell. Her relatives and friends kept commenting about them, and wherever she went, everyone would stare at her. She admitted to having low self-esteem because of these disfiguring lesions. She subsequently underwent laser therapy at a private medical clinic. Unfortunately, the lesions did not improve so she decided to discontinue the treatment as it was quite costly.

A depression screen performed during this consultation did not show that she was depressed. Her latest blood laboratory results showed good glycemic and blood lipid control. She was advised to continue her current medications. She was also referred to a dermatologist for further assessment and management of her extensive facial skin lesions. A skin biopsy performed by the dermatologist showed well-circumscribed dermal nests of basaloid cells, with peripheral palisading, and keratin horn cysts surrounded by a dense fibrous stroma (Figure 5). These features were consistent with trichoblastoma. There was no evidence of malignancy. She was then referred to a plastic surgeon to discuss further management options. These options include serial carbon dioxide laser ablation, full thickness excision, full thickness skin graft, or reconstructive surgery. Laser treatment was chosen after detailed discussion with the patient.

Discussion

Trichoblastoma is a rare, benign cutaneous adnexal neoplasm arising from rudimentary hair follicles. There is a lack of data on its incidence and prevalence in the general population. However, most cases present in adults aged 40 years and older [1]. Trichoepithelioma is a subset of trichoblastoma, in which the neoplasm is composed of smaller islands of basaloid cells, occasionally just 1 or 2 cells thick, with significant fibrosis [1]. Trichoepithelioma may be associated with genetic conditions or syndromes such as Brooke-Spiegler disease and Brooke-Fordyce syndrome [2–4]. However, most cases are isolated and sporadic, and present with solitary lesions [5].

The main differential diagnosis for trichoblastoma is basal cell carcinoma (BCC), as both conditions may resemble each other clinically and dermatoscopically [6]. BCC of the skin is the most common type of cancer in humans [7]. It rarely metastasizes, but local invasion may lead to destruction of skin and other deeper tissues [8]. In contrast, trichoblastomas generally have a very low rate of malignant transformation [1]. Hence, both conditions require a histopathological diagnosis from a skin biopsy, to prevent undertreatment or overtreatment. Based on histological appearance, trichoblastoma can be further categorized as large nodular, small nodular, retiform, cribriform, race-miform, or columnar [4]. The presence of papillary-mesenchymal bodies, which are cuplike proliferations of basaloid cells engulfing fibroblasts, is a characteristic finding [2]. In comparison with BCC, the stroma of trichoblastoma is tightly associated with the basaloid epithelial cells, and there is a distinct demarcation between the periepithelial stroma and the surrounding dermal collagen [2].

Given the excellent prognosis, simple trichoblastoma may be managed with just ongoing clinical followup. As extensive trichoblastoma is very rare, there is a dearth of published evidence on the best management strategies and their success rates. Several treatment modalities have been proposed [1]. Mohs micrographic surgery is an option [9,10]. Nonsurgical destructive therapies, including curettage, cryosurgery, electric cautery, and laser resurfacing have also been used for multiple small tumours, depending on the lesion sizes, location, and depth [4,10–12]. For this patient, laser treatment was chosen as she was fearful of the other, more invasive options. From the available literature on laser ablation for trichoblastoma, it has shown good cosmetic results, good recovery, and minimal adverse effects [10]. Given the risk of recurrence [4,10], this patient will continue to be followed up at our primary care clinic for this condition, as well as for hypertension and diabetes management.

Conclusions

We present a very rare case of extensive facial trichoblastoma that highlights the need for clinicians to ensure optimal exposure when examining patients. This is especially relevant during this COVID-19 pandemic, when the usage of personal protective equipment may affect our ability to perform a thorough examination. This case also highlights the role of biopsies for skin lesions of uncertain etiology. It also serves as a reminder about the need for ongoing review and referral for further management for conditions when treatment is unsuccessful.