PD‐1 inhibitor‐associated lichenoid inflammation with incidental suprabasilar acantholysis or vesiculation—Report of 4 cases

Abstract

Lichenoid drug reaction occurring in patients receiving anti-PD1 therapy may be associated with microscopic suprabasal or intraepidermal clefting. The clinical course was similar to lichenoid drug reactions without clefting even though some lesions may resemble PP microscopically.

Lichenoid dermatitis from immune checkpoint inhibitor therapy: An immune‐related adverse event with mycosis‐fungoides‐like morphologic and molecular features

“…In conclusion, lichenoid inflammatory infiltrate of the skin is a frequent morphologic pattern seen in patients receiving ICI therapy. Emerging morphologic lichenoid patterns include prominent epidermal hyperplasia, suprabasal acantholysis, and paraneoplastic‐pemphigus‐like features . We report lichenoid dermatitis with MF‐like features including monoclonal TCR gene rearrangement as another lichenoid inflammatory pattern that may occur with ICI therapy.…”

Suprabasal acantholytic dermatologic toxicities associated checkpoint inhibitor therapy: A spectrum of immune reactions from paraneoplastic pemphigus‐like to Grover‐like lesions

“…A summary of the suprabasal acantholytic dermatologic toxicities associated CPIs reported in the literature (including the two patients in this report) is presented in Table . Overall, 13 patients (including the two in this report) with a median age of 64 years (range: 51‐75 years) developed suprabasal acantholytic dermatologic toxicities (Grover‐like, n = 8; “lichenoid dermatitis with suprabasal acantholysis/intraepithelial vesicle”, n = 4; PNP‐like, n = 1) associated with CPIs (ipilimumab = 4; nivolumab = 2; pembrolizumab = 2; combined CPIs = 5).…”

“…Whereas autoimmune blistering processes that histopathologically exhibit subepidermal clefting with morphologic features similar to those of BP or dermatitis herpetiformis have been long described in association with CPIs, suprabasal acantholysis with associated lichenoid inflammation in patients treated with CPIs was a more recently recognized pattern, initially described by Chou et al In their report, examination of skin biopsies from two patients revealed suprabasal clefts with acantholytic cells involving the epidermis, as well as follicular epithelium in one patient. The differential diagnosis included PNP and Grover disease; however, neither clinical nor immunologic findings supported an autoimmune blistering disorder or Grover disease despite histologic features simulating either PNP or Grover disease (transient acantholytic dyskeratosis) . Patient 1 in the current report represents a suprabasal, acantholytic CPI‐associated autoimmune blistering disease with PNP‐like features restricted to histopathology and immunofluorescence.…”

“…Adverse events from CPIs that manifest as dermatologic toxicities include a spectrum of clinical and histologic morphologic features . Some reported CPI‐associated dermatologic toxicities include lichenoid dermatitis, bullous pemphigoid (BP), and granulomatous/sarcoid‐like lesions …”

“…Grover‐like (transient acantholytic dermatosis) eruptions associated with CPIs rarely occur and account for less than 1% of reported dermatologic toxicities treated with anti‐CTLA‐4 and anti‐PD‐1 antibodies . Suprabasal acantholysis or vesicle formation with negative autoantibodies is now recognized as a form of lichenoid dermatologic toxicity associated with CPIs . The histologic differential includes pemphigus vulgaris, paraneoplastic pemphigus, and Grover disease.…”