Skin Deep: A Fascinating Case Report of Immunotherapy-Triggered, Treatment-Refractory Autoimmune Lichen Planus and Keratoacanthoma

Lesions in the oral mucosa associated with the use of checkpoint inhibitors: A bibliometric and critical review

AIMS

Immune-related adverse events (irAEs) linked to the use of immune checkpoint inhibitors (ICIs) have become increasingly frequent. To perform a bibliometric and critical review of the general panorama of publications on oral mucosal lesions (OML) associated with ICIs.

METHODS AND RESULTS

Systematized searches were performed in four databases. The included studies were organized and bibliometric and clinical data were extracted and analyzed using VantagePoint and Microsoft Excel. Most of the 35 included studies were reports or case series (n = 33/94.2%). The American authors stood out (n = 17/48.5%), with the majority presenting only one publication. Independent groups carried out most of the publications (n = 31/88.5%). Over the years, publications have increased for users of nivolumab and pembrolizumab. In 21 studies (60%), OML were more common in men, between the 6th and 9th decades of life and who had lung carcinoma (n = 13/37.1%). Pembrolizumab (n = 17/48.5%) was the most used ICI. The patients were affected by one or more OML, including: ulcers (n = 28/80%) and erythema (n = 11/31.4%). Systemic corticosteroids (n = 24/68.5%) and the discontinuation of ICI use (n = 18/51.4%) were the main approaches used.

CONCLUSION

OML related to the use of ICIs have become increasingly common. More accurate data need to be published.

A retrospective cohort study of the efficacy of metronidazole in oral lichen planus

Lichen planus (LP) is an inflammatory dermatosis with mucosal variants, including oral LP (OLP). OLP has a relapsing chronic course and may significantly affect a patient's quality of life. We analysed the efficacy of metronidazole as a treatment for OLP via a retrospective chart review of patients with a diagnosis of OLP seen at our institution over 10 years. Thirty patients with OLP were treated with metronidazole 500 mg twice daily. Most patients (n = 18; 60%) showed improvement with metronidazole, including 10 (33%) who experienced complete resolution of symptoms. Our results were limited by the retrospective nature of the review and the relatively small cohort size. Given the efficacy, mild side-effect profile and the less immunosuppressive nature of metronidazole vs. alternative systemic treatment options, metronidazole is a reasonable option to try in patients with symptomatic OLP who have failed topical treatment options.

Pembrolizumab-Induced Eruptive Keratoacanthomas and Lichen Planus in a Lung Cancer Patient

Reports of pembrolizumab-induced lichen planus and eruptive keratoacanthomas are limited in the literature. Here, we describe the unique concurrence of both lichen planus and eruptive keratoacanthomas in a patient who received pembrolizumab for non-small cell lung cancer (NSCLC). Although several therapies have been proposed, we show that pembrolizumab-induced lichen planus and keratoacanthomas can be controlled with the conservative management of topical corticosteroids and intralesional corticosteroids, respectively, allowing patients to continue pembrolizumab therapy.

Risk of Lichen Sclerosus and Lichen Planus in Patients Receiving Immune Checkpoint Inhibitors

INTRODUCTION

Immune checkpoint inhibitors (ICIs) are recommended for various types of cancer. On the other hand, these ICIs may cause immune-related adverse events (irAEs). Lichen sclerosus (LS) and lichen planus (LP) are two distinct phenotypes of irAEs that occur in a subset of patients treated with ICIs. These adverse effects have a detrimental effect on the patient's quality of life and treatment phases; however, the clinical evaluation and assessment of LS and LP remain uncertain. This study aims to assess and evaluate the risk of LS and LP associated with the use of ICIs via a systematic review of the literature and the USA FDA Adverse Events FAERS database.

METHOD

The study searched electronic databases such as PubMed, Medline, Cochrane, and Google Scholar for case reports on immune-checkpoint-inhibitor-associated lichen sclerosus and lichen planus published in English between inception and 31 December 2021. The FDA's adverse event reporting system (FAERS) database was also analyzed.

RESULTS

Thirty-eight case reports and two retrospective studies with a total of 101 patients, in addition to the FAERS data, were evaluated. More cases involved lichen planus (78.9%) than lichen sclerosis (21%). Nivolumab and pembrolizumab were most frequently reported with LS and LP, among other ICIs. Thirty-six out of thirty-eight patients with LS or LP experienced complete remission, while two patients experienced partial remission. Most of the cases had an excellent response to corticosteroids (92.1%), while the remainder had moderate (5.2%) and poor (2.6%) responses. Additionally, the reporting odds ratio (ROR) of the FAERS database indicated a favorable association for ICIs, the risk of LP, and LS. A stronger association was uniquely found between nivolumab and pembrolizumab.

CONCLUSION

There have been published case reports for these adverse events. Healthcare providers should be aware of the possibility of lichen sclerosis and lichen planus developing in patients receiving ICIs which could necessitate hospitalization or discontinuation. Regulatory agencies are advised to monitor the risks as a potential safety signal.

To treat or not to treat: PD-L1 inhibitor-induced keratoacanthoma and squamous cell carcinoma

Keratoacanthoma (KA) and squamous cell carcinoma (SCC) are rare side effects of programmed cell death ligand-1 (PD-L1) inhibitors that can disrupt therapy. There is no consensus on optimal treatment. We investigated the management strategy and factors influencing pathophysiology. An institutional cancer registry and literature search were used for this retrospective study. Only PD-L1-induced KA and SCC cases were included. Pathology specimens were stained with immune markers and management strategies were analyzed. Four cases were identified at our institution. Immunohistochemistry of atypical keratinocytes revealed PD-1/PD-L1 positivity, high p53, and low bcl-2 for all cases with differential expression of CD44 and beta-catenin for KA versus SCC. Nivolumab was continued or temporarily held with complete resolution. In addition, a literature search identified 30 additional cases of KA/SCC after PDL-1 inhibitor use. The most common treatment was excision/destruction followed by topical and/or intralesional corticosteroids. Therapy was definitely withheld in 22% of KA patients and in 9% of SCC cases. The expression of PD-L1 by atypical keratinocytes helps to explain the effects of nivolumab on the development of cutaneous neoplasms. The expression of immune markers provides mechanistic insights into pathophysiology. Management may be achieved with conservative therapy and without treatment interruption.