Shudo Bull Natl Res Cent (2021) 45:56 https://doi.org/10.1186/s42269-021-00514-0 Bulletin of the National Research Centre CASE REPORT Open Access Histopathological specialized staining of oral lichen planus-induced fbrotic changes and surgical treatment of associated restricted mouth opening: a case report Atsushi Shudo1,2* Abstract Background: Oral lichen planus is a chronic infammatory and immune-mediated disease that afects the oral mucosa. Recent fndings have suggested that oral lichen planus is often associated with submucosal fbrotic changes. Fibrotic changes in the buccal submucosa may cause restricted mouth opening. This report discusses the histopatho- logical examination (including specialized staining) and surgical treatment for oral lichen planus-induced fbrotic changes. Case presentation: Here, we describe a 63-year-old woman who had oral lichen planus with fbrotic changes. Her maximum mouth opening distance was approximately 30 mm due to submucosal fbrotic changes, and she exhib- ited gradual fbrosis progression. Histological examinations were performed to assess the oral lichen planus-induced fbrotic changes. Then, double Z-plasty were performed as treatment for restricted mouth opening. The immunohis- tochemical staining results were negative for cytokeratin 13 and positive in some layers for cytokeratin 17 and Ki-67/ MIB-1. Masson’s trichrome staining showed enhanced collagen formation. Postoperative mouth opening training enabled the patient to achieve a mouth opening distance of > 50 mm. Conclusion: Our fndings suggest that histopathological examination with specialized staining can aid in the evalua- tion of oral lichen planus-induced fbrotic changes, and that Z-plasty is efective for the treatment of restricted mouth opening due to oral lichen planus. Keywords: Oral lichen planus, Submucosal fbrotic changes, Restricted mouth opening, Z-plasty, Case report Background mucosa (Nogueira et al. 2015). Except in patients with Oral lichen planus (OLP) is a relatively common disease the pathognomonic appearance of reticular OLP (i.e., of the squamous epithelia and is regarded as a T-cell- bilateral white striae on the buccal mucosa), histopatho- mediated chronic infammatory disease of unknown logic evaluation of lesional tissue is generally required to etiology (Scully and Carrozzo 2008). OLP is character- obtain a defnitive diagnosis (Edwards and Kelsch 2002). ized by white striations (Wickham’s striae), white pap- Common histopathological features of OLP are hydropic ules, white plaques, mucosal erythema, and atrophic degeneration of the basal layer and band-like chronic erosions, all of which predominantly afect the buccal lymphocytic infammatory infltrate in the subepithelial layer (Anitua et al. 2019). *Correspondence: [email protected] Recently, it has been suggested that some types of OLP 1 Department of Oral and Maxillofacial Surgery, Kishiwada Tokushukai may be associated with submucosal fbrotic changes, Hospital, Kishiwada, Osaka, Japan which are regarded as OLP-induced fbrotic changes Full list of author information is available at the end of the article © The Author(s) 2021. 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In previous reports, the term "submucosal fbrotic bands in OLP" has been used (Shteiner et al. 2020), potentially to distinguish from a similar lesion, oral submucosal fbrosis (OSF). Te causes of these two lesions are diferent, but they are similar in that they are associated with fbrotic change-induced restricted mouth opening (RMO). Patients with severe RMO (< 35 mm) have lower quality of life (Scott et al. 2008); therefore, treatment may be needed. Tere have been some studies regarding treatment for OSF-induced RMO (Mehrotra et al. 2009); to the best of our knowledge, there have been no reports of treatment for OLPFC-induced RMO. In addition, there have been no reports of histopathological examinations that include Fig. 1 Clinical presentation, intraoral view. The lesion had been specialized staining for OLPFCs. Tis report describes diagnosed as oral lichen planus following biopsy at another hospital, histopathological examination including immunostain- 4 years before the patient’s frst visit to my department ing and collagen staining for OLPFCs; it also discusses Z-plasty as a surgical treatment. Importantly, the term “trismus” is generally used to indicate radiation-induced fbrosis of masticatory muscles and should not be used as a general term for patients with RMO (Satheeshkumar et al. 2014). Terefore, in this report, the term RMO is used consistently. Case presentation Tis article demonstrates a typical OLPFC and OLPFC- induced RMO. A 63-year-old woman was referred to our outpatient clinic for further evaluation of RMO due to OLP. Her lesion had been diagnosed as OLP based on the results of a biopsy performed at another hospital, 4 years prior to her frst visit to our department. At that time, the OLP was not associated with RMO. Beginning Fig. 2 Preoperative measurement photograph. The patient’s at 6 months before the frst visit to our clinic, the patient maximum mouth opening distance was approximately 30 mm experienced gradual mucosal induration, which resulted in RMO. At the time of presentation, the patient was a nonsmoker, had no exposure to areca nuts, and had no remarkable prior medical history and family medical which were typical of OLP: hydropic degeneration of the history. basal layer, band-like chronic lymphocytic infammatory Initial clinical examination revealed a scar-like white infltrate in the subepithelial layer, hyperkeratosis, sharp lesion on the right buccal mucosa, which contained white serrated ridges of epithelial processes, and Civatte bod- plaques and mucosal erythema (Fig. 1). Te lesion exhib- ies (Fig. 4). Enhanced fbrotic changes were also indicated ited strong induration and had led to RMO; the patient’s by hematoxylin–eosin staining. Terefore, collagen fber maximum mouth opening distance was approximately staining (Masson’s trichrome staining) was performed, 30 mm (Fig. 2). Magnetic resonance imaging showed no which revealed the progression of distinct fbrosis, espe- neoplastic lesions and was suggestive of a scar-like lesion cially around infltrated lymphocytes in the subepithelial due to infammation. Te masseter muscle had been sep- layer (Fig. 5). Elastica van Gieson staining did not reveal arated from the lesion; it had become hypertrophic, but any proliferation of elastic fbers. Immunohistochemical remained intact (Fig. 3). staining (based on the characteristics of "oral potentially Te histological diagnosis of OLP had been made prior malignant disorders" in OLPs) showed negative cytokera- to the initial presentation to our clinic. However, consid- tin 13 (CK13) fndings, as well as positive cytokeratin ering the possibility of lesion progression, another histo- 17 (CK17) fndings in the epithelium layer and positive logical examination was performed. Hematoxylin–eosin Ki-67/MIB-1 fndings primarily in the basal layer (Fig. 6). staining revealed the following histopathological features, Shudo Bull Natl Res Cent (2021) 45:56 Page 3 of 6 Fig. 4 Hematoxylin–eosin staining revealed histopathological features typical of oral lichen planus. a Magnifcation, 20. b × Magnifcation, 100 × Fig. 3 Magnetic resonance imaging results were suggestive of a scar-like lesion due to infammation. The masseter muscle had been separated from the lesion and remained intact. a Axial plane (short T1 inversion recovery). b Coronal plane Te lesion was not associated with pain or discom- fort unique to OLP; however, treatment of RMO was needed. Band-shaped indurated mucosal excision and Z-plasty were performed with the patient under local Fig. 5 Masson’s trichrome staining revealed distinct fbrosis, anesthesia. Basic Z-plasty, in which two triangular faps especially around infltrated lymphocytes in the subepithelial layer ( 20) of equal dimension are transposed, was presumed to × interfere with the maxillary–mandibular gingiva and parotid papilla due to the larger incision line. Tere- fore, a double Z-plasty technique was applied (Fig. 7). the patient’s mouth opening distance improved to No induration was observed in the muscular layer; 38 mm (Fig. 8). In addition to conducting our profes- thus, surgery was performed only in the mucosal epi- sional opening training, continuous self-training was thelium and lamina propria. Immediately after surgery, instructed. Eight months after the surgery, the mouth opening distance improved to > 50 mm (Fig. 9). Shudo Bull Natl Res Cent (2021) 45:56 Page 4 of 6 Fig. 7 Intraoperative view. a Designated incision line (solid line: Fig. 6 Immunohistochemical staining results