The significance of eosinophils in hypertrophic lichen planus

Abstract

Hypertrophic LP is a distinct variant of LP that may show variable numbers of eosinophils and should be included in the differential diagnosis of lichenoid dermatitis with eosinophils.

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

“…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…”

Update on lichen planus and its clinical variants

“…While exact pathophysiology has not been clarified, eosinophils may play a larger role in hypertrophic LP than in other variants (Alomari and McNiff, 2014). It is likely that the Koebner phenomenon also plays a role in the pathogenesis of these lesions.…”

Red Alert or Red Herring?

“…Similarly, elsewhere in this issue of the JCP , Alomari and McNiff have assessed the frequency of tissue eosinophilia in the context of interface dermatitis and have demonstrated that eosinophils are not uncommon in association with hypertrophic LP. This may come as formal validation of a longstanding impression for many, but standard textbook references were not yet savvy to this phenomenon . Eosinophils can be identified in both conventional and hypertrophic LP but are 6–7 times more common in the latter condition.…”

“…Eosinophils can be identified in both conventional and hypertrophic LP but are 6–7 times more common in the latter condition. Curiously, eosinophils were noticeably more common in hypertrophic LP involving the trunk in comparison to involvement of the leg . That said, hypertrophic LP was very much confirmed to be a disease bound by gravity, as the eruption was limited to the leg 90% of the time (in distinct contrast, conventional LP is a disease of the arm in nearly 70% of patients).…”

“…Should they be paid great heed, ignored from time to time, or both? In no particular order, some thoughts, bon mots , and shots follow: The combined observations of Fung, McNiff, and colleagues render it clear that eosinophils do not quash a diagnosis of LP. Just as eosinophils in the context of spongiotic dermatitis seem to hold no particular predictive value regarding etiologic triggers, eosinophils in a lichen planus‐like dermatitis probably hold no special meaning.…”