Solitary painful ulcerated plaque on the sole.

Sir,

A 40-year-old lady presented with a painful ulcerated plaque over the sole of the right foot since four months [Figure 1]. She gave a history of thorn prick prior to onset of symptoms, followed by discoloration and ulceration. Multiple courses of antibiotic were prescribed without relief. Cutaneous examination revealed a single well-defined plaque of 3 cm × 6 cm on the right sole. The surface of the plaque was ulcerated and crusted, with blackish hyperpigmentation and erythema. Mucocutaneous examination, and examination of the draining lymph nodes were unremarkable. Acral lentiginous melanoma, Bowen's disease, lupus vulgaris, and atypical mycobacterial infection were considered in the clinical differentials. Punch biopsy was done from the margin of the lesion. Histological examination showed hyperkeratosis without parakeratosis, focal hypergranulosis, irregular acanthosis, mononuclear cell infiltration in upper dermis, and foci of basal layer degeneration [Figure 2a–c]. Additionally, there were some changes consistent with reactive eccrine syringofibroadematosis. Routine laboratory tests including serum biochemistry panel were absolutely normal. Based on the clinical and histological findings, a diagnosis of ulcerative lichen planus (LP) of the sole was made. She was given intralesional triamcinolone at monthly interval and potent topical steroids under occlusion. There was a satisfactory response, but the lesions did not resolve completely at the end of 2 months. Oral prednisolone was then started at a dose of 1 mg/kg/day, resulting in rapid resolution of the lesion. She has been under regular follow up, and no recurrence has been noted.

Figure 1

Single ulcerated plaque on sole

Figure 2

(a) Hyperkeratosis without parakeratosis, acanthosis, hypergranulosis, and mononuclear cell infiltration in upper dermis (a; H and E, ×40). Note basal layer degeneration (b; H and E, ×400) and (c; H and E, ×400)

Ulcerative or erosive LP is a rare variant of LP that predominantly affects the oral cavity and genitalia. Plantar location is uncommon and only few cases have been reported in medical literature. It was first described by Friedman in 1921.[1] It is difficult to diagnose ulcerative LP of the sole, especially when it appears as an isolated finding as seen in our case. It usually starts as erythema and bullae on the feet, eventually progressing to develop painful ulcers. Patients have chronic, progressive, crippling, erosive and ulcerative lesions resulting in scarring and deformities.[2] Atypical locations have been reported in a few cases, such as the pretibial zone and flexural areas.[3] Many authors have proposed the association of ulcerative LP and autoimmune diseases, mainly autoimmune thyroiditis, primary biliary cirrhosis, diabetes mellitus, rheumatoid arthritis, and Sjögren's syndrome.[4] The clinical differentials include severe eczema, localized bullous pemphigoid on the soles, and plantar erythrodysesthesia caused by anticancer drugs like gefitinib.

Since the condition is rare, a well-accepted therapeutic modality is yet to be discovered.[5] Many modalities are reported to provide symptomatic relief without any long term cure rates, leading to recurrences. A few authors have found systemic steroids beneficial in the long term management of ulcerative LP.[6] There are reports of successful use of intralesional triamcinolone acetonide, low molecular weight heparin,[7] platelet-derived growth factor,[1] and topical tacrolimus. Close follow-up is required as verrucous carcinoma is known to develop in long-standing cases of ulcerative LP; however, the exact incidence of malignancy is not yet known. Our case had additional features of reactive eccrine syringofibroadematosis on histopathology; the latter is a known association of ulcerative LP.[8]