Keratoacanthoma centrifugum marginatum: a rare atypical variant of keratoacanthoma

Abstract

Keratoacanthoma centrifugum marginatum (KCM) is an extremely rare variant of keratoacanthoma (KA), with about 30 cases reported since it was first described in 1962. Clinically, KA is an exoendophytic lesion of 10-25 mm with a horn-filled crater that resolves spontaneously within 6 months. In contrast, KCM is characterized by a larger diameter continuous centrifugal spread, concurrent central atrophy and lack of spontaneous remission. Histologically, KCM is similar to KA, with a central keratin-filled crater, overhanging lips of epithelium, a sharp outline between the tumour nests and stroma, and lack of anaplasia and stroma desmoplasia. We describe a 63-year-old agricultural worker with a 9-month history of a multinodular tumour, 70-75 mm in size, on his right hand. The clinical diagnosis of KCM was confirmed by histological examination. Local radiotherapy proved effective, with no recurrence during a 4-year follow-up.

Keratoacanthoma: a distinct entity?

“…Unusual vertical growth invading dermal and underlying tissue is observed . Subungual KA is a rare KA variant, appearing under nails, show rarely spontaneous regression and may destroy the terminal phalanx . Mucosal KA another extremely rare KA variant, has also no tendency to regress and is observed mostly intraorally . Since intraoral mucous membranes bear no follicles it was suggested, that these KA may arise from ectopic sebaceous glands . Keratoacanthoma centrifugum is a rare exoendophytic type, characterized by multifollicular origin, progressive peripheral expansion (2–40 cm) and atrophic central healing . Resolving of the tumor occurs spontaneously and involution is mostly complete within week 12 .…”

Keratoacanthoma centrifugum marginatum at an unusual site

“…It is an acquired disorder of adulthood with no genetic predisposition. [4] The etiology is multifactorial that includes chronic ultraviolet ray exposure, smoking, contact with chemical carcinogens like pitch, mineral oil, tar, trauma and vaccination. [5] The role of human papilloma virus remains inconclusive but in one study, HPV type 6 and 11 were detected within the lesion.…”

Keratoacanthoma centrifugum marginatum: unresponsive to oral retinoid and successfully treated with wide local excision.

“…2 After the exclusion of the clinical mimickers, KCM was diagnosed on the basis of classical clinical and histopathological findings. The appearance of recurrent nodular skin lesions with central clearing and progressive peripheral spreading on the distal extremities, 6 in the setting of the histopathological findings of large irregularly shaped craters filled with keratin, with irregular epidermal proliferation having a glassy appearance and not extending below the level of the sweat glands, was diagnostic of KCM. The findings in our case were similar to those of previous case reports with the presence of large lesions and no tendency to spontaneous resolution.…”

“…6 Diagnosis of the condition was a real challenge in our case and meticulous clinical and histopathological examinations were required to differentiate it from several other conditions that closely mimic KCM. The clinical differential diagnoses include squamous cell carcinoma (SCC), lupus vulgaris (LV), botryomycosis, blastomycosis-like pyoderma (BLP), and pseu- doepitheliomatous hyperplasia (PEH).…”