Pityriasis Lichenoides Chronica of Esophagus: A Rare Case Report

Pityriasis lichenoides chronica (PLC) is an uncommon inflammatory skin condition of unknown cause that ranges from a mild chronic form to a more severe acute eruption. Both forms usually involve the skin of the trunk and proximal extremities, and visceral involvement is not a well-described phenomenon. Here, we report a case of PLC that presented with esophageal involvement that occurred after a period of discontinuation of PLC treatment. The histological pattern of involvement is in the form of lymphocytic esophagitis, a non-specific pattern with a broad differential diagnosis. Awareness of the potential involvement of the esophagus and attention to certain endoscopic and morphological details may better help classify esophagitis biopsies and the diagnosis of this rare non-neoplastic chronic inflammatory disease. To our knowledge, this is the first-ever case of PLC with esophageal involvement, and nothing has been reported in the English literature earlier.


Introduction
Pityriasis lichenoides, an uncommon interface dermatitis, is an inflammatory skin condition of unknown cause that ranges from mild chronic form to a more severe acute eruption. The mild form, pityriasis lichenoid chronica (PLC) or guttate parapsoriasis is characterized by the gradual development of nonsymptomatic, small brown-red scaling papules that spontaneously flatten and regress over weeks or months [1]. The acute form is characterized by the sudden eruption of small-scaling papules that develops into blisters and crusted red-brown spots. This acute condition is referred to as pityriasis lichenoides et varioliformis acuta (PLEVA) and its most severe form is known as febrile ulceronecrotic Mucha-Habermann disease. Histologically, PLEVA presents as a brisk perivascular lymphocytic infiltrate with interface change and wedge-shaped reticular dermis extension, whereas PLC demonstrates blunted features of PLEVA with focal apoptotic keratinocytes [2]. Both forms usually involve the skin of the trunk and proximal extremities. Although certain interface dermatitis, such as lichen planus, can simultaneously present with esophageal manifestation, visceral mucosal involvement in PLC is not a well-described phenomenon, and no esophageal involvement has been previously reported in the literature [2][3][4].

Case Presentation
The patient is a 69-year-old female with a significant history of cutaneous PLC, hyperlipidemia, and endometriosis. Her past surgical history is significant for appendectomy, hysterectomy, cholecystectomy, and colonoscopy. Her PLC has been well-controlled for the past one and half years by immunosuppressive therapy, Methotrexate sodium 2.5 mg/6 weekly. Apart from immunosuppressive therapy, she is also on clotrimazole, folic acid, prednisolone acetate, vitamin D, and tropical neomycin-polymyxin-HC 3.5-10,000-10 mg-unit-mg/ml/daily.
Recently, the patient presented with odynophagia, dysphagia, and cough. Further questioning revealed that the patient has difficulty continuing her PLC medication because of dysphagia. She also reported very infrequent symptoms of pyrosis one time/month treated by over-the-counter antacids. The patient also reported multiple episodes of oral thrush treated with Diflucan and oral mouthwash. Due to her bothersome oral symptoms, an upper endoscopy examination was performed. Endoscopy showed diffuse edema and the mid and distal esophagus was dry, erythematous, and narrowed due to the presence of strictures. Random, multiple, cold-forceps upper esophageal biopsies were obtained.
Grossly, the biopsy specimen consisted of a few, tiny, tan-pink esophageal mucosal fragments. Microscopic evaluation revealed multiple fragments of esophageal squamous mucosa showing a band-like inflammatory infiltrate ( Figure 1A), with diffuse lymphocytes exocytosis (intraepithelial lymphocytosis), acanthosis, basal cell hyperplasia with prominent apoptotic keratinocytes identified ( Figures 1B-1D). The inflammatory infiltrate was composed predominantly of CD3+ T-lymphocytes with scattered plasma cells and macrophages. There was no significant acute inflammation and no increase in intraepithelial eosinophils. Immunohistochemistry stains for CD3, CD8, and CD20 showed the majority of inflammatory cells consisting of CD3-positive T-lymphocytes with a predominance of CD8-positive cytotoxic T-cells (Figures 2A-2B). No viral or fungal organisms were demonstrated on periodic-acid-Schiff (PAS), cytomegalovirus (CMV), and herpes simplex virus type 1 (HSV-1) stains.

Discussion
The esophagus is frequently involved in several primary dermatologic conditions including lichen planus, lichen sclerosis, acanthosis nigricans, and bullous skin diseases. Other conditions that may involve the skin and the esophagus include infections, connective tissue diseases, drug-induced injury, Crohn's disease, and graft-versus-host disease. Esophageal involvement may coincide with or occur after dermatological manifestations. Rarely, esophageal involvement occurs in the absence of dermatologic disease or may even precede it [2][3].
Clinical manifestations of esophageal involvement by skin diseases include dysphagia, odynophagia, and stricture formation sometimes leading to weight loss and findings concerning for malignancy. Malignant transformation has been rarely reported in association with esophageal lichen planus [5]. It is, however, speculated that most of the cases of esophageal involvement in dermatologic diseases are clinically silent, and the condition is significantly underreported and underdiagnosed. Rarely, hematemesis and death have been reported secondary to lichen planus and certain blistering diseases [6].
Endoscopic examination of the esophagus involved in skin conditions mostly shows nonspecific findings, including stricture, white papules, pinpoint erosions, esophageal pseudo-membranes, and inflamed mucosa [3]. These findings may simulate reflux esophagitis, eosinophilic esophagitis, and fungal or viral esophagitis. Therefore, a biopsy is necessary to distinguish this cutaneous-esophageal condition from other primary esophageal disorders. The histologic pattern of involvement is often in the form of "lymphocytic esophagitis," referring to an abundance of intraepithelial lymphocytes and associated marked spongiosis. The term "lichenoid esophagitis" was primarily proposed by Salaria et al. for a pattern of inflammation in the esophagus, which is similar to lichenoid interface dermatitis [2]. It is characterized by a T-lymphocyte predominant subepithelial band-like inflammatory infiltrate, increased intraepithelial lymphocytosis, acanthosis, and single necrotic squamous cells (Civatte bodies). This pattern is not specific, however, and it has been described in association with drugs, viral infections, esophageal Crohn's disease, and pill-induced esophagitis in addition to lichen planus as well as in our case of PLC.
Pityriasis lichenoides is a term used to describe the unique group of acquired inflammatory skin disorders that includes pityriasis lichenoides chronica (PLC), pityriasis lichenoides et varioliformis acuta (PLEVA), and febrile ulceronecrotic Mucha-Habermann disease (FUMHD) variant of PLEVA. PLC is clinically characterized by the development of multiple scaly, asymptomatic red-brown, erythematous, small-sized papulosquamous lesions appearing in crops commonly involving the buttocks, trunk, and upper extremities. The condition usually has a relapsing and remitting course that persists for months or years [7].
The epidemiology of PLC is inconclusive due to limited data in the published literature and the different clinical subtypes sharing similar presentations. PLC typically affects children and young adults but can develop at any age, including in older individuals. [8]. At present, the pathogenesis of PLC is unknown and poorly understood. However, it is hypothesized that some parasitic infections (Toxoplasma gondii), viral (Epstein-Barr virus, parvovirus B16, HIV), and bacterial infections (staphylococci, Group A streptococci) might be the trigger for the development of PLC [9][10][11]. The characteristic histopathological features of cutaneous PLC include acanthosis, parakeratosis, mild spongiosis, sparse necrotic keratinocytes, hyperplasia of the basal cell layer, lymphocytes exocytosis, and lichenoid band-like perivascular lymphohistiocytic infiltrate in the superficial dermis and epidermis [12].
The diagnosis of esophageal PLC requires a biopsy and relies on clinical history, endoscopic findings, and histopathological features. The morphology shares significant overlapping features with other forms of lymphocytic (lichenoid) esophagitis.
A few skin conditions that mimic PLC, their clinical presentation, and potential esophageal involvement, in addition to therapeutic options, are listed in  PLC is a benign disease that is nonscarring, often asymptomatic, and self-limiting in nature. There is no clear consensus and guidelines for the PLC treatment because of a paucity of high-quality efficacy data and the benign course of the disease. Multiple prophylactic treatment modalities are available for including firstline therapy with topical corticosteroids, oral antibiotics, and phototherapy. More aggressive treatment with immunomodulatory agents like methotrexate is reserved for severe refractory cases [18]. In our case, the patient is in remission and actively being treated with topical and oral immunosuppressive therapy as discussed in the case presentation.

Conclusions
PLC is a rare disorder that imposes diagnostic and therapeutic challenges on clinicians. When this rare entity is clinically suspected, a biopsy is recommended to confirm the diagnosis by histology. PLC does not have a specific treatment, but this condition responds well to topical corticosteroids, immunosuppressants, and phototherapy. Antibiotics can also be used in case of secondary bacterial infections. The purpose of this case report is to provide awareness of esophageal involvement by PLC and to bring attention to certain endoscopic and morphological details of this entity that might better help classify esophagitis causes.

Additional Information Disclosures
Human subjects: Consent was obtained or waived by all participants in this study. Conflicts of interest: In compliance with the ICMJE uniform disclosure form, all authors declare the following: Payment/services info: All authors have declared that no financial support was received from any organization for the submitted work. Financial relationships: All authors have declared that they have no financial relationships at present or within the previous three years with any organizations that might have an interest in the submitted work. Other relationships: All authors have declared that there are no other relationships or activities that could appear to have influenced the submitted work.