Clinico-Dermatoscopic Study of Lichen Planus With Histopathological Correlation

INTRODUCTION

Lichen planus (LP) is a chronic papulosquamous disease that affects the skin, mucous membranes, nails, and hair.^[1] The natural course of the disease without treatment is usually prolonged, but spontaneous resolution has been seen in a few cases.^[2] Cell-mediated immunity plays a major role in triggering clinical expression of the disease.^[3] The pathogenesis of lichen planus can be divided into three stages: antigen recognition, followed by cytotoxic lymphocyte activation, and then apoptosis of the keratinocytes.^[4]

Fine white reticulate networks seen over LP lesions are known as Wickham’s striae (WS).^[5–8] Some common types of cutaneous LP, according to configuration, are annular, linear, blaschkoid, and zosteriform, and according to morphology, they are classic, hypertrophic, atrophic, actinic, lichen plano pilaris, and lichen planus pigmentosus.^[9,10] Typical papules of LP show the following features on histopathology^[11,12]: compact hyperkeratosis, wedge-shaped hypergranulosis, irregular acanthosis, vacuolar alteration of the basal layer, band-like dermal lymphocytic infiltrate in close approximation to the dermis. Pigmentary incontinence is seen due to the accumulation of dermal melanophages.^[13]

The diagnosis of LP is usually clinical and is often supplemented with histopathological examination (HPE) in cases of diagnostic dilemma. Dermatoscopy is a newer modality for the early and non-invasive diagnosis of LP, showing WS, vascular structures (especially red dots and radial capillaries), and hyperpigmentation (brownish diffuse or deeper dotted patterns).^[14] Dermatoscopy enhances diagnostic accuracy by correlating microscopic histopathology with clinical features. Being non-invasive, it is useful where histopathology facilities are unavailable and offers an alternative to invasive biopsies, particularly for cosmetically concerned patients.

Most of the recent studies on LP focus on Fitzpatrick skin types 1 and 2, highlighting the need for studies on various dermatoscopic patterns in skin types 3, 4, and 5. Only one study comparing dermatoscopic and histopathological features was found after a thorough search of the literature, which was conducted in South India by Jose et al.^[14] This is the first study on North Indian skin involving all variants of lichen planus and with a relatively long duration of study.

MATERIAL AND METHODS

The prospective observational study was conducted on patients attending the Dermatology Outpatient Department (OPD) at a tertiary care centre in North India over 2 years, from September 2022 to August 2024. Ethical clearance from the Institutional Ethical Committee was obtained for the same. Written informed consent in a language understandable to the patient was obtained.

A convenience sampling method was employed, wherein patients of all age groups with newly clinically diagnosed cutaneous LP were included in the study. Patients currently undergoing treatment for lichen planus, those with exclusively mucosal or nail involvement, and individuals who did not provide consent for dermatoscopic and histopathological examination were excluded. Clinical examination findings were recorded on a proforma designed for the study.

Dermatoscopic examination and biopsy were performed after clinical diagnosis. Biopsy specimens were prepared using routine haematoxylin and eosin (H&E) stain for conventional histopathological diagnosis. Clinical pictures of the cutaneous lesions of the patient were taken using the Android mobile phone, with a green/blue background and under appropriate lighting conditions. Dermatoscopy was performed on the most representative lesion in these patients using the dual-mode Iluco^TM dermatoscope. The following dermatoscopic findings were noted: vascular morphology, arrangement of vascular morphology, background, and non-vascular findings.

The site for the biopsy was determined based on a clinical-dermatoscopic assessment of the lesion’s morphology, size, and location. Department of Pathology assessed histopathology slides and following histopathological examination findings were noted: epidermal findings, dermo epidermal junction (DEJ) findings, dermal findings, and appendageal findings.

Using a proforma, patient details, clinical findings, dermatoscopic findings, and histopathological findings were recorded. All the data collected were analysed statistically. Dermatoscopic and histopathological correlation was assessed using Cohen’s kappa coefficient.^[15] All statistical calculations were performed using the International Business Machine Statistical Package for the Social Sciences (IBM SPSS) version 27.

RESULTS

In our study, the most common age group was 31–40 years (39.2%) [Table 1]. A female preponderance was observed (56.9% of cases), with a female-to-male ratio of “1.31:1” [Table 1]. The most common site involved was the upper limb (31.5% of cases). Most of the patients in our study had a disease duration of 1–3 months [39 (38.3%)] [Table 1]. Classic lichen planus (CLP) [59 (57.8%)] constituted the majority of patients in our study, followed by Hypertrophic Lichen Planus (HLP) [18 (17.7%)] [Table 1]. Dermatoscopic and histopathological findings of different variants of LP are depicted in Tables 2 and 3, respectively.

CLP dermatoscopy revealed red globules (42.4%) as the most common vascular morphology and WS (94.9%) as the predominant non-vascular finding. Histopathology of CLP showed hyperkeratosis (86.4%) as the most frequent epidermal finding and lichenoid infiltrate (100%) at the dermo-epidermal junction [Figure 1]. HLP dermatoscopy revealed red globules (66.7%) as the most common vascular morphology, with patchy and peripheral arrangements (44.4% each). Non-vascular findings included WS, grey-blue dots, and follicular plugging (77.8% each), with comedo-like openings in 66.7% of cases. Histopathology of HLP showed hyperkeratosis (100%) as the predominant epidermal finding and lichenoid infiltrate (100%) at the dermo-epidermal junction. Follicular plugging (66.7%) was observed in appendageal findings [Figure 2].

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Figure 1:

(a) Classic lichen planus over the dorsal aspect of the hands and forearm, (b) Classic lichen planus over the ventral aspect of the hands and forearm, (c) Dermatoscopy [20x, polarised mode] showing Wickham’s striae in a leaf venation pattern (black box) over a violaceous background; red globules (red curved arrow) and grey-blue dots (yellow arrow) in a blue box, (d) Histopathology (haematoxylin and eosin, 10x) showing hyperkeratosis (black box), focal hypergranulosis (red arrow), acanthosis, and lichenoid infiltration at the interface.

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Figure 2:

(a) Hypertrophic lichen planus over the shin, (b) Closer view of Hypertrophic lichen planus over the left shin, (c) Dermatoscopy [10x, polarised mode] showing Wickham’s striae in reticular pattern (black box) over a grey-blue background with comedo-like openings (blue arrow), corn pearls (yellow arrow), follicular plugging (red arrow), and yellow-brown dots (blue circle), (d) Histopathology (haematoxylin and eosin, 10x) showing hyperkeratosis (black box), follicular plugging (red arrow), acanthosis with elongated rete ridges (yellow arrow), lichenoid infiltration at the interface, and pigmentary incontinence (blue box) in dermis.

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Dermatoscopy of lichen planus pigmentosus (LPP) demonstrated a Hem-like pattern in 70% of cases. Histopathology of LPP revealed atrophy (80.0%) and pigmentary incontinence (100.0%). Dermatoscopy of lichen plano pilaris (LPPI) demonstrated arboriform vessels in 4 (66.7%) cases, arranged in a diffuse pattern, and decreased hair density (100% each). On histopathology of LPPI, atrophy, perivascular infiltrate, and pigmentary incontinence were observed in 4 (66.7%) cases each. Follicular plugging (83.3%) was the most common appendageal finding [Figure 3]. The dermatoscopic and histopathological findings of linear lichen planus (LLP) and zosteriform lichen planus (ZLP) were similar to those of CLP. In contrast, the dermatoscopic and histopathological features of blaschkoid lichen planus (BLP) resembled those of LPP.

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Figure 3:

(a) Lichen plano pilaris over scalp (right lateral view), (b) left lateral view, (c) over scalp (vertex), (d) Dermatoscopy [20x, polarised mode] showing perifollicular scales (yellow arrows), grey-blue dots (red arrow), and violaceus background with loss of hairs (black box) (e) Histopathology (haematoxylin and eosin, 10x) showing follicular plugging (blue arrow), hyperkeratosis (black box), and perifollicular infiltrate (yellow arrow).

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Correlation of dermatoscopic and histopathological findings showed varying levels of agreement across different variants of LP [Table 4]. In CLP, WS showed slight agreement with hyperkeratosis (kappa = 0.11) and fair agreement with hypergranulosis (kappa = 0.21), suggesting a stronger correlation with hypergranulosis. Grey-blue dots on dermatoscopy and pigmentary incontinence on histopathology demonstrated fair agreement (kappa = 0.34). For HLP, WS and hypergranulosis showed moderate agreement (kappa = 0.55). In LPPI, perifollicular scales on dermatoscopy and follicular plugging on histopathology showed fair agreement (kappa = 0.25).

DISCUSSION

This study is an attempt to examine the dermatoscopic features of different variants of lichen planus and to correlate dermatoscopic findings with histopathological findings. Most of the patients belonged to the age group of 31–40 years [40 cases (39.2%)] with a mean age of 38.50 years and a standard deviation of 10.24 years. This was in concordance with studies by Kachhawa et al.^[16], where the most common age group affected was 20 to 39 years (45.7%), and Ireddy et al.^[17], where the most common age group affected was 20–39 years (46.9%).

Out of 102 patients, 58 (56.9%) were females, and 44 (43.1%) were males, with a female-to-male ratio of 1.31:1 which was in accordance with Gavvala et al.^[18] Boyd et al.^[19] and Garg et al.^[20] Female preponderance can be attributed to the autoimmune nature of the disease and relatively more cosmetic concern in females. The most common site involved in our study was the upper limb (UL), followed by the lower limb (LL), seen in 32 (31.5%) and 26 (25.6%) cases, respectively. Most of the patients had a disease duration of 1–3 months [39 (38.3%)]. Although inflammatory skin diseases are usually of chronic duration and most patients present late in the disease course, the relatively early presentation (less duration) in our study can be attributed to the fact that only new cases were included in our study.

In our study, CLP constituted the majority of patients [59 (57.8%)], followed by HLP [18 (17.7%)]. Similar observations were also made by Gavvala et al.,^[18] Kaur et al.,^[20] Horatti et al.,^[21] Reddy et al.,^[22] Srivani et al.,^[23] and Maisnam et al.^[24] Dermatoscopy of CLP showed red globules (42.4%) and WS (94.9%) as common findings. Light red was the most frequent background colour, with yellow-brown dots seen in 40.7% of cases. These findings were consistent with those of Gavvala et al.,^[18] Reddy et al.,^[22] Shekhar S Haldar et al.,^[25] and F. Vazquez-Lopez et al.^[26] In a study by Jose S et al.,^[14] WS was found in 92.6% of cases, followed by comedo-like openings (CLO) (49.1% of cases). In a similar study in North India by Kaur et al.,^[20] WS was the most common finding (93.33% of cases), followed by bluish-black to brown pigmentation (73.3% of cases), CLO (20% of cases), and vascular structures (33.3% of cases). Studies on dermatoscopy of Classic LP showed variability, but Wickham’s striae were consistently common across all racial groups. Differences in background pigment and vascular patterns in our study may be due to the darker skin type of our patients.

Dermatoscopy of HLP had many similarities to that of CLP, with the presence of CLO in 66.7% of cases, but follicular plugging (77.8%) was key to differentiating HLP from CLP. Our study’s findings were consistent with that of Gavvala et al.^[18] with Wickham’s striae and comedo-like openings being common findings. Reddy et al.^[22] also observed red globules in 16.67% of cases and noted brown and blue-black pigmentation, consistent with our results. Interestingly, both of the studies mentioned above didn’t observe any follicular plugging; they may have described these findings as comedo-like openings.

A few specific features on dermatoscopy of LPP were perifollicular halos (differentiate from melasma), hem-like pattern, and absence of WS, consistent with studies by Reddy et al.^[22] and Neema et al.^[27] Granular pigmentation along skin creases and sparing of skin creases was seen in 70% of cases, likely due to lower UV exposure in the creases. Similar findings were observed by Kaur et al.^[20] and Shekhar S. Haldar et al.^[25]. The dermatoscopic findings of LPPI showed arboriform vessels, follicular plugging, reduced hair density, and perifollicular scales. These findings were similar to those noted by Friedman et al.^[28], who also found follicular plugging, perifollicular scaling, erythema, and arboriform vessels in early-stage LPPI. Güngör et al.^[29] reported similar findings, including WS in 40% of patients. In contrast, our study did not observe WS, possibly due to earlier patient presentation, when erythema is more prominent.

On dermatoscopy of ALP, faint blotchy erythema and a pigmented pseudo network were observed, which were in concordance with findings of Kothari et al.^[30] Dermatoscopy findings of linear lichen planus and zosteriform lichen planus were similar to those of CLP, and dermatoscopy of Blaschkoid lichen planus was similar to LPP. It seems that these are arrangement patterns of the disease rather than discrete entities.

Histopathological examination of the CLP revealed that hyperkeratosis, hypergranulosis, lichenoid infiltrate, and pigmentary incontinence were common findings. These were in concordance with findings by Srivani et al.,^[23] Horatti LB et al.,^[21] Jose S et al.,^[14] Kaur et al.,^[20] and Maisnam et al.^[24] Hyperkeratosis was noted in all cases of HLP, and in contrast to CLP, follicular plugging was observed in 66.7% of cases. Histopathological examination of LPP revealed epidermal atrophy in 80% of cases and pigmentary incontinence in 100% of cases, which is consistent with the findings of Kaur et al.^[20] Atrophy was also noted in 66.7% of cases of LPPI, and follicular plugging was reported in 83.3% of cases. Hyperkeratosis, acanthosis, and atrophy were seen in two (50.0%) cases, each on HPE of ALP.

The correlation of dermatoscopic findings with histopathological features in classic lichen planus showed slight agreement between WS and hyperkeratosis (kappa = 0.11), consistent with study by Reddy et al.^[22] (kappa = 0.06). A stronger correlation was observed between WS and hypergranulosis (kappa = 0.21), in line with findings by Jose S et al.^[14] (kappa = 0.24). Grey-blue dots on dermatoscopy correlated fairly with pigmentary incontinence (kappa = 0.34), consistent with findings by Reddy et al.,^[22] Jose S et al.,^[14] and Kaur et al.^[20]; although Reddy et al.,^[22] and Jose et al.^[14] did not calculate the kappa value.

The correlation of dermatoscopic and histopathological findings in hypertrophic lichen planus revealed moderate agreement between WS and hypergranulosis (kappa = 0.55), in concordance with findings by Reddy et al.^[22] and Kaur et al.^[20] This indicates that WS is the clinical representation of hypergranulosis in histopathology. In Lichen Plano Pilaris, grey-blue dots showed perfect agreement with pigmentary incontinence (kappa = 1), while arboriform vessels correlated fairly with perivascular infiltrates (kappa = 0.25).

CONCLUSION

Over the years, while clinical diagnosis has been key to diagnosing lichen planus, histopathology remains the gold standard in cases of diagnostic uncertainty. Biopsies can be difficult, particularly in paediatric patients, as well as for facial and scalp lesions. Dermatoscopy offers a non-invasive, cost-effective alternative, linking clinical and histopathological findings, and can often eliminate the need for biopsies. Dermatoscopy is effective in diagnosing lichen planus variants, correlating clinical and histopathological features, and assessing pigmentation depth. Its non-invasive, portable nature makes it a beneficial tool, reducing the financial and physical burden on patients, especially in the era of increased cosmetic awareness.