Keratoacanthoma: a distinct entity?

Abstract

Keratoacanthoma (KA) are common but exceptional benign tumors, often appearing on sun-exposed areas of light skinned people and showing spontaneous resolution. The goal of this study was to review existing literature, to point out the etiological complexity of KA biology and to answer the controversial debate if or not KA is a distinct entity or a variant of squamous cell carcinoma (SCC). Relying on recent results, we highlight that KA is an individual lesion with a unique molecular signature caused by alterations in the TGFb signalling pathway. These recent findings will help to understand the nature of KA and to develop new reliable diagnostic tools, simplifying the discrimination of the histologically similar KA and SCC.

The genetic evolution of skin squamous cell carcinoma: tumor suppressor identity matters

“…In contrast, KRAS activation coupled with Rb1 deletion led to benign papillomas, and hypertrophy of the infundibulum and sebaceous glands. Similarly, KRAS activation coupled with Pten deletion caused squamous hyperplasia eventually leading to papillomas or keratoacanthomas, and benign tumors of the skin characterized by rapid growth and spontaneous regression . This study is in agreement with the observation that Tp53 is mutated in a high percentage of human cSCCs, whereas Pten and Rb1 are infrequently mutated.…”

Pembrolizumab‐induced pseudoepitheliomatous eruption consistent with hypertrophic lichen planus

“…Nevertheless, keratoacanthomas have been reported in the literature secondary to pembrolizumab therapy . While some argue that keratoacanthomas and SCC are two distinct entities, others consider keratoacanthomas to be a more benign subtype of SCC that typically will self‐resolve within a few months . Keratoacanthomas have also been described in patients taking nivolumab, another PD‐1 inhibitor .…”

Oncogenic ALKF1174L drives tumorigenesis in cutaneous squamous cell carcinoma

“…The presence of the luciferase (luc) reporter gene in the ALK transgene allowed us to monitor tumor development using IVIS imaging system (Heukamp et al, 2012) (Fig 1D). Based on the histological examination (Gleich et al, 2016), we distinguished four types of skin lesions, including cysts (n = 5 mice), acanthopapilloma (AP) (n = 7 mice), keratoacanthoma (KA) (n = 7 mice), and cSCC type 1 (n = 8 mice) (Figs 1E and F and S1D and E). Similarly, the targeted expression of ALK F1174L using another HF stem cell-specific Cre line, K15-CrePR1 (Morris et al, 2004), resulted in cSCC development ( Fig 1G).…”