Focus of tricholemmal differentiation (tricholemmal carcinoma) within Bowen's disease/carcinoma

Systematic analysis and case series of the diagnosis and management of trichilemmal carcinoma

Background

Trichilemmal carcinoma (TLC) is a rare malignant cutaneous adnexal neoplasm, with no relatively comprehensive research.

Objective

The aim of this study is to perform an updated statistical analysis so as to better understand TLC's epidemiology, clinical features, diagnosis, and treatment.

Methods

The diagnosis and treatment of three TLC cases in our department were summarized. Then, all TLC cases published in the literature were retrieved for a comprehensive analysis, followed by the analysis of global trends and regional distribution, demographic characteristics, clinical features, pathogenesis, histopathological features, and treatment and prognosis of TLC.

Results

Of the 231 cases, the incidence of TLC has shown an upward trend recently, especially in China, in Asia. The susceptible population is men aged 60-80 and women over 80, and the most prone location is head and neck. The phenotype of TLC is not always typical and may be misdiagnosed because of the coexistence of other diseases. There is a linear relationship between the diameter and its duration or thickness. UV, locally present skin lesions, trauma, scarring, organ transplantation, and genetic disorders may trigger the occurrence of TLC. Periodic acid-Schiff staining and CD34, but not Epithelial Membrane Antigen (EMA), were helpful in the diagnosis of TLC. Although effective, surgical excision and Mohs micrographic surgery need further improvement to reduce recurrence of TLC. Carcinoma history is an independent risk factor for TLC recurrence.

Limitations

The limitation of this study is the lack of randomized controlled trial on TLC treatment and recurrence.

Conclusion

TLC has the possibility of invasive growth and recurrence, especially in patients with longer duration and carcinoma history.

Bowen's Disease

Bowen's disease (BD) is an in-situ squamous cell carcinoma of epidermis. The etiology of BD is multifactorial with high incidence among Caucasians. BD is common in photo-exposed areas of skin, but other sites can also be involved. Lesions are usually solitary. The morphology of BD differs based on age of the lesion, site of origin, and the degree of keratinization. BD is considered as the "lull before the storm," which precedes an overt squamous cell carcinoma. Histopathology is the gold standard diagnostic modality to confirm the diagnosis. Immunohistochemistry, dermoscopy, and reflectance confocal microscopy are the adjuvant modalities used in the diagnosis of BD. The treatment depends on various factors like site, size, immune status, patient's age, esthetic outcome, etc. The available therapeutic modalities include topical chemotherapy, surgical modalities, light-based modalities, and destructive therapies. It requires a combined effort of dermatologist, oncosurgeon, and plastic surgeon to plan and execute the management in various presentations of BD.

Bowen disease with matrical differentiation: Report of an exceptional histopathologic presentation

Matrical differentiation is the distinctive feature of pilomatricoma and other purely matrical adnexal neoplasms; additionally, foci of matrical differentiation have been also described in hybrid cysts of Gardner syndrome, as well as in a wide variety of benign and malignant cutaneous tumors, including basal cell carcinoma. We report an exceptional case of Bowen disease exhibiting multiple foci of matrical differentiation, as confirmed by means of immunohistochemical studies. Several types of divergent, non-squamous differentiation have been exceptionally reported in cutaneous squamous cell carcinoma in situ (cSCCIS), including sebaceous, mucinous/glandular, poroid, tricholemmal, and neuroendocrine differentiation; matrical differentiation may be added to this list. Our findings further emphasize the undifferentiated nature of neoplastic cells in cSCCIS.

Cutaneous Squamous Cell Carcinoma: Review of the Eighth Edition of the American Joint Committee on Cancer Staging Guidelines, Prognostic Factors, and Histopathologic Variants

Cutaneous squamous cell carcinoma is the second most common form of nonmelanoma skin cancer after basal cell carcinoma and accounts for the majority of nonmelanoma skin cancer-related deaths. In 2017, the American Joint Committee on Cancer revised the staging guidelines of cutaneous squamous cell carcinoma to reflect recent evidence concerning high-risk clinicopathologic features. This update reviews the literature on prognostic features and staging, including the eighth edition of the American Joint Committee on Cancer Staging Manual. A wide range of histopathologic variants of cutaneous squamous cell carcinoma exists, several of which are associated with aggressive behavior. A review of cutaneous squamous cell carcinoma variants, emphasizing diagnostic pitfalls, immuhistochemical findings and prognostic significance, is included. Of note, the eighth edition of the American Joint Committee on Cancer Staging Manual refers to squamous cell carcinoma of the head and neck only.