Hypertrophic lichen planus: masquerading as squamous cell carcinoma

Abstract

SummaryWe present two cases of hypertrophic lichen planus mistaken for squamous cell carcinomas which were excised on multiple occasions. With appropriate histopathological review and treatment with topical corticosteroids, the 'lesions' showed significant improvement with near resolution at six months. This highlights the clinically difficulty with distinguishing hypertrophic lichen planus from squamous cell carcinoma. On literature review, mucosal lichen planus has a well known associated risk of squamous cell carcinoma, however, there have been isolated case reports of squamous cell carcinoma arising from hypertrophic lichen planus.KEY WORDS: hypertrophic lichen planus; squamous cell carcinoma; keratoacanthoma; topical corticosteroids. Case based review Case 1A 76-year-old male presented to a general surgeon in 2009 with a right pretibial nodule present for several months which was thought to be squamous cell carcinoma (SCC). It was excised and reported as lichen simplex chronicus. In 2010, he had his first recurrence of the right pretibial nodule and underwent another excision, which was reported as an atypical squamoproliferative lesion, clear of resection margins with keratoacanthoma favoured over well differentiated SCC. He then had a second recurrence of a right pretibial nodule in 2012 and had a third excision which was reported as a well differentiated SCC completely excised with changes of lichen simplex chronicus. In February 2013 he then presented with multiple nodular lesions on his left lower leg, with a biopsy reporting well differentiated SCC and a recurrent nodule on the right lower leg which was reported was well differentiated SCC. However due to the unusual presentation of bilateral leg involvement he was referred to the Peter MacCallum Cancer Centre. A PET scan was performed as is the standard practice for metastatic SCC at this hospital which showed extensive nodular lesions in left lower leg and right medical calf lesion which were FDG avid. There was no evidence of nodal or distant spread. On dermatology review, he had very little background solar damage or features of such as solar keratoses and SCC-in-situ (Bowen's disease) and had no predisposing factors such as immunosuppression or drug therapy which would be expected in a patient with multiple SCCs. On further examination, he had multiple pruritic violaceous plaques on bilateral lower legs, arms and scalp (Figure 1). It was felt generalised hypertrophic lichen planus was the unifying diagnosis. There was no evidence of mucosal lichen planus. Biopsies were then performed of a left arm plaque which was reported as hypertrophic lichen planus and of a right leg nodule as pseudoepitheliomatous hyperplasia associated with hypertrophic lichen planus but well differentiated SCC could not be excluded. Histopathology review of all the earlier biopsies showed the 2009 biopsy as hypertrophic lichen planus over an old scar, the 2010 right lower leg biopsy as keratacanthoma which was completely excised, the February 2013 left lower leg biopsy sho...

Hypertrophic lichen planus mimicking squamous cell carcinoma: The importance of clinicopathologic correlation

“…This case underscores the importance of recognizing HLP as a mimicker of SCC to avoid unnecessary interventions and ensure timely initiation of appropriate treatment. At least 4 patients with HLP mistaken as SCC have been reported in the literature, highlighting the challenge of identifying the correct diagnosis 2, 3…”

“…Like other chronic inflammatory conditions associated with rubbing and irritation, HLP may be associated with features of pseudoepitheliomatous hyperplasia (PEH), which can be difficult to distinguish from SCC 2, 6. PEH is characterized by hyperplasia of the epidermis and adnexal epithelium, gross irregular acanthosis, and horn cyst formation 2, 3, 6. However, unlike SCC, PEH does not infiltrate into the reticular dermis or invade blood vessels, nerves, or lymphatics 2, 3…”

“…PEH is characterized by hyperplasia of the epidermis and adnexal epithelium, gross irregular acanthosis, and horn cyst formation 2, 3, 6. However, unlike SCC, PEH does not infiltrate into the reticular dermis or invade blood vessels, nerves, or lymphatics 2, 3…”

“…A deep biopsy section should be obtained if HLP is suspected; superficial biopsy specimens may not include a sufficient portion of the dermis to differentiate between HLP and SCC 6 . Histologic features suggestive of HLP include hyperorthokeratosis, wedge-shaped hypergranulosis, and psoriasiform hyperplasia of the epidermis 5 ; lichenoid interface dermatitis with eosinophils 10 ; presence of typical features of PEH; and absence of cytologic atypia, marked solar elastosis, deep extension beyond the superficial dermis, and lymphovascular or perineural invasion 2, 3. Elastic staining to visualize the presence or absence of perforating elastic fibers may assist in distinguishing between SCC and HLP; perforating elastic fibers are rarely present in HLP but may be seen in SCC 11, 12…”

Vulvar hypertrophic lichen planus

“…Cложность дифференциальной диагностики гипертрофического КПЛ вульвы с ПКР кожи связана и с возможностью злокачественной трансформации первого [8]. О важности различия этих процессов свидетельствуют четыре описанных в литературе случая ошибочной диагностики ПКР при гипертрофическом КПЛ [4,9].…”